11th International Conference “PROBLEMS OF GEOCOSMOS”...
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St. Petersburg State University 11th International Conference “PROBLEMS OF GEOCOSMOS” Book of Abstracts St. Petersburg, Petrodvorets, October 3–7, 2016 St. Petersburg 2016
Transcript of 11th International Conference “PROBLEMS OF GEOCOSMOS”...
St. Petersburg State University
11th International Conference
“PROBLEMS OF GEOCOSMOS”
Book of Abstracts
St. Petersburg, Petrodvorets, October 3–7, 2016
St. Petersburg
2016
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Program Committee Prof. V.S. Semenov Prof. N.V. Erkaev Prof. M. Hayakawa Dr. V.P. Kalvarskaya Prof. B.M. Kashtan Dr. P.V. Kharitonskii Prof. Yu.A. Kopytenko Dr. S.S. Krylov Prof. A.A. Namgaladze Dr. A.A. Kosterov Prof. V.N. Troyan Prof. V.A. Sergeev Dr. E.S. Sergienko Dr. N.A. Smirnova Dr. A.A. Samsonov Dr. N.A. Tsyganenko Prof. T.B. Yanovskaya
Chairman, St.Petersburg University, Russia Institute of Computational Modelling SB RAS, Russia The University of Electro-Communications, Japan EAGU, Russia St.Petersburg University, Russia St.Petersburg University, Russia SPbF IZMIRAN, Russia St.Petersburg University, Russia Arctic University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia St.Petersburg University, Russia
Organizing Committee S.V. Apatenkov, vice-chairman N.Yu. Bobrov M.V. Bondarev V.V. Karpinsky M.V. Kholeva A.A. Kosterov M.V. Kubyshkina E.L. Lyskova N.P. Legenkova I.A. Mironova A.A. Samsonov E.S. Sergienko R.V. Smirnova T.A. Kudryavtseva
sergey
Typewritten Text
ISBN 978-5-9651-1002-5
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CONTENTS
STP. SOLAR-TERRESTRIAL PHYSICS ................................................. 24 ON SOLUTION ACCURATENESS OF A SOUTHERN BOUNDARY DETERMINATION IN THE CASES OF UREP EVENTS Astafiev A.M., Remenets G.F. .................................................................... 24 SUPRAMOLECULAR PHYSICS OF THE SOLAR-TROPOSPHERE LINKS: CONTROL OF THE CLOUD COVER BY SOLAR FLARES AND MAGNETIC STORMS Avakyan S.V. .............................................................................................. 26 SUPRAMOLECULAR PHYSICS OF THE IONOSPHERE – BIOSPHERE LINKS Avakyan S.V. .............................................................................................. 27 GEOMAGNETIC ACTIVITY STRUCTURES OF MAGNETIC CLOUDS Barkhatov N.A., Revunova E.A., Vinogradov A.B., Romanov R.V., Yagodkina O.I. ............................................................................................ 28 SOLAR WIND DRIVING AND FORMATION OF SUBSTORM ACTIVITY Barkhatov N.A., Yagodkina O.I., Revunov S.E., Vorobjev V.G. ................ 29 GEOMAGNETIC AND IONOSPHERIC RESPONSE TO SSC AS OBSERVED BY THE COMPLEX OF INSTRUMENTS Belakhovsky V.B., Pilipenko V.A., Baddeley L., Sakharov Ya.A., Samsonov S.N. ........................................................................................... 30 ENERGIZATION OF THE OUTER RADIATION BELT ELECTRONS DUE TO WAVE-PARTICLE INTERACTION Belakhovsky V.B., Pilipenko V.A., Samsonov S.N. ................................... 31 ARE THE ORBITAL INSOLATION VARIATIONS, OR CO2 OSCILLATIONS, THE MAIN DRIVERS OF THE PLEISTOCENE GLACIAL CYCLES? Bol'shakov V.A. .......................................................................................... 31 MANIFESTATION OF METEOROLOGICAL STORM IN VARIATIONS OF THE TOTAL ELECTRON CONTENT IN KALININGRAD REGION Borchevkina O.P., Karpov I.V., Karpov A.I. ............................................... 32
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RECOGNITION OF RADIO PULSES FROM LIGHTNING STROKES Cherneva N.V., Vodinchar G.M., Mochalov V.A., Druzhin G.I., Sannikov D.V., Malysh E.A., Mochalova A.V. ........................................................... 33 HIGH-LATITUDE IONOSPHERIC IRREGULARITIES: DIFFERENCES BETWEEN GROUND- AND SPACE-BASED GPS MEASUREMENTS DURING THE 2015 ST. PATRICK'S DAY STORM Cherniak Iu., Zakharenkova I. .................................................................... 34 AURORA AS MARKER OF GPS/GLONASS SIGNALS PROPAGATION Chernouss S.A., Shagimuratov I.I., Filatov M.M., Efishov I.I., Ievenko I.B., Shvec M.V., Tepenitsina N.Yu., Kalitenkov N.V., Kopytenko Yu.A. ......... 36 PROPERTIES OF FREQUENCY DISTRIBUTION OF PC5-RANGE PULSATIONS OBSERVED WITH THE EKATERINBURG DECAMETER RADAR IN THE NIGHTSIDE IONOSPHERE Chtlpanov M.A., Mager O.V., Mager P.N., Klimushkin D.Yu., Berngardt O.I. .............................................................................................................. 37 OSCILLATIONS OF 2D INHOMOGENEOUS MHD-WAVEGUIDE IN THE OUTER MAGNETOSPHERE Chuiko D.A., Mazur V.A. ........................................................................... 38 IDENTIFICATION OF THE SOURCE OF QUASIPERIODIC VLF EMISSIONS USING GROUND-BASED AND VAN ALLEN PROBES SATELLITE OBSERVATIONS Demekhov A.G., Titova E.E., Kozelov B.V., Pasmanik D.L., Manninen J., Santolik O., Kletzing C.A., Reeves G. ........................................................ 39 POYNTING FLUX DIRECTIONS OF VLF CHORUS EMISSIONS IN THEIR SOURCE REGION AS INFERRED FROM THEMIS DATA Demekhov A.G., Taubenschuss U., Santolik O. .......................................... 40 2-D MODEL OF THE IONOSPHERIC CONDUCTOR Denisenko V.V. ........................................................................................... 41 CLIMATIC PERIODICITIES IN THE VARVE THICKNESESS OF THE PRECAMBIAN ELATINA FORMATION AND SOLAR ACTIVITY CYCLICIITY Dergachev V.A., Dmitriev P.B., Tyasto M.I. ............................................... 42 NATURE OF THE 2300-YEAR CYCLE OBSERVED IN THE CONCENTRATION OF COSMOGENIC ISOTOPES Dergachev V.A., Vasiliev S.S. ..................................................................... 43
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AURORAL DISTURBANCES DURING ST. PATRICK'S DAY GEOMAGNETIC STORMS IN 2013 AND 2015 Despirak I.V., Kozelov B.V., Guineva V. .................................................... 44 HIGH LATITUDE SUBSTORMS DURING THE 23-TH AND 24-TH SOLAR CYCLES Despirak I.V., Lyubchich A.A., Kleimenova N.G. ...................................... 45 STORM-TIME ELECTRON TEMPERATURE AND DENSITY AT R=6-11 RE (EMPIRICAL MODELS) Dubyagin S., Ganushkina N., Sillanpää I., Runov A. ................................. 46 PREDICTION OF MAXIMUM DAILY RELATIVISTIC ELECTRON FLUX AT GEOSTATIONARY ORBIT BY ADAPTIVE MODELS Efitorov A., Myagkova I., Dolenko S. ........................................................ 46 ACCELERATION OF PLASMA FLOW IN THE MAGNETOSHEATH DUE TO MAGNETIC FIELD DRAPING Erkaev N.V., Farrugia C.J., Mezentsev A.V., Ivanov V.A. ......................... 48 HALL MHD SIMULATION OF THE MAGNETIC RECONNECTION AT THE MAGNETOPAUSE Erkaev N.V., Mezentsev A.V., Ivanov V.A., Dement'eva E.V. ................... 48 ANALYTICAL MODEL OF DOUBLE GRADIENT MHD WAVES IN CASE OF NON-SYMMETRIC MAGNETOTAIL CURRENT SHEET Erkaev N.V., Semenov V.S., Kubyshkina D.I., Ryzhkov I.I., Kozlova S.V.49 AN INFLUENCE OF THE HALL MHD EFFECT ON THE MAGNETIC BARRIER FORMATION Erkaev N.V., Mezentsev A.V., Ivanov V.A., Dement'eva E.V. ................... 50 THE SPATIAL DISTRIBUTION OF THE ULF MAGNETIC FIELD OF MULTIBAND PC1 FREQUENCIES Ermakova E.N., Shennikov A.V., Kotik D.S., Pershin A.V., Yahnin A.G., Yahnina T.A. ............................................................................................... 51 ANALYSIS OF METHODS FOR ESTIMATING EQUIVALENT IONOSPHERIC CURRENT FROM MERIDIAN MAGNETOMETER CHAIN DATA Evdokimova M.A., Petrukovich A.A. ......................................................... 52 WAYS TO PROVIDE THE FLIGHT SAFETY OF ORBITAL SPACECRAFT’S WITH IT’S OUTER ATMOSPHERE MONITORING Gaponov V.A., Kavtrev S.S. ....................................................................... 53
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INTERPRETATION OF PLASMA SHEET FLAPPING OSCILLATIONS CONJUGATE TO THE EAST-WEST AURORAL ARCS IN THE IONOSPHERE Golovchanskaya I.V., Mingalev I.V., Kornilova T.A. ................................. 54 THE SUBSTORM CYCLE AS REPRODUCED BY COMMUNITY-AVAILABLE GLOBAL MHD MODELS Gordeev E., Sergeev V., Tsyganenko N., Kuznetsova M., Raeder J., Toth G., Merkin V. .................................................................................................... 55 SECONDARY MHD WAVES IN THE MAGNETOSHEATH BEFORE THE MAGNETOSPHERE OF THE EARTH Grib S.A., Leora S.N. ................................................................................. 56 HIGH-LATITUDE GEOMAGNETIC RESPONSE TO THE SPACE WEATHER DURING THE INTENSE MAGNETIC STORM ON JUNE 22-23, 2015 Gromova L.I., Kleimenova N.G., Gromov S.V., Dremukhina L.A., Levitin A.E., Zelinsky N.R., Malysheva L.M. ........................................................ 57 MANIFESTATIONS OF THE INTENSE CONVECTION AND SUBSTORM IN THE EVENING MLT SECTOR FROM THE OBSERVATIONS BY THE ALL-SKY IMAGER Ievenko I.B., Parnikov S.G., Alexeyev V.N. ............................................... 58 SAR ARC OBSERVATIONS IN THE EVENTS OF ENERGETIC PLASMA OVERLAPPING WITH A PLASMAPAUSE BY THE VAN ALLEN PROBE DATA DURING THE STORM AND SUBSTORM Ievenko I.B. ................................................................................................ 59 INVESTIGATION OF THE PС5 EVENT IN THE AFTERNOON SECTOR Ismagilov V.S., Kopytenko Yu.A. ............................................................... 60 SPACE ENVIRONMENT MODELS AND OPERATIONAL SERVICES IN SPACE WEATHER Kalegaev V.V. ............................................................................................. 61 OPERATIONAL CONTROL OF GEOSPACE RADIATION CONDITIONS IN SPACE MONITORING DATA CENTER OF MOSCOW STATE UNIVERSITY Kalegaev V.V., Myagkova I., Bobrovnikov S., Barinova V., Eremeev V., Mukhametdinova L., Nguyen M.D., Shugau Yu. ....................................... 62
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IMPACT OF SOLAR PROTON EVENTS ON THE CHEMICAL COMPOSITIONS OF THE POLAR ATMOSPHERE Karagodin A.V., Mironova I.A. .................................................................. 63 MAGNETOTAIL FAST FLOWS NEAR LUNAR ORBIT Kiehas S., Runov A., Angelopoulos V. ....................................................... 64 STRUCTURE OF THE HELIOSPHERIC PLASMA SHEET Kislov R.A., Khabarova O.V., Malova H.V. ............................................... 64 CHANGE OF POLARIZATION OF THE LONG-PERIOD ALFVEN WAVES IN DIPOLE-LIKE MAGNETOSPHERE: THEORY AND OBSERVATIONS Klimushkin D.Yu., Leonovich A.S., Mager P.N. ........................................ 65 DO THE FACTORS OF SPACE WEATHER ON FAILED MISSILE LAUNCHES? Klyushnikov V.Yu, Kozlov S.I., Nagorskiy P.M., Tasenko S.V. ................. 66 E-REGION OF THE IONOSPHERE DURING 2015 ST. PATRICK'S DAY GEOMAGNETIC STORM Korenkov Yu.N., Bessarab F.S., Klimenko V.V., Klimenko M.V. .............. 67 WAVE-LIKE AURORAL ACTIVITIES PRECEDING SUBSTORM ONSET Kornilova T.A., Golovchanskaya I.V. ......................................................... 68 2D LINEARIZED MHD SIMULATIONS OF FLAPPING OSCILLATIONS Korovinskiy D.B., Ivanov I.B., Semenov V.S., Erkaev N.V., Kiehas S.A. . 68 ESTIMATION OF EFFECTIVE HEIGHT CHANGES OF EARTH-IONOSPHERE WAVEGUIDE USING PHASE VARIATIONS OF LOW AND VERY LOW FREQUENCY RADIO SIGNALS DURING A SOLAR ECLIPSE Korsakov A.A., Kozlov V.I., Karimov R.R. ............................................... 69 MAGNETOSPHERE-IONOSPHERE INTERACTION IN THE AURORAL REGION DURING SUBSTORM ACTIVATIONS Kozelova T.V., Kozelov B.V., Turyansky V.A. ........................................... 70 NUMERICAL SIMULATIONS OF GLOBAL DYNAMICS AND PHOTOCHEMISTRY OF EARTH’S MIDDLE ATMOSPHERE. SOLAR ACTIVITY INPUT Krivolutsky A.A. ......................................................................................... 71
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SIMULATION OF THE UPPER ATMOSPHERE DISTURBANCES PRODUCED BY ACOUSTIC-GRAVITY WAVES PROPAGATED FROM THE SOLAR TERMINATOR IN THE TROPOSPHERE Kurdyaeva Y.A., Karpov I.V., Borchevkina O.P., Vasilev P.A., Kshevetskii S.P. .............................................................................................................. 72 RESONANT WAVE-PARTICLE INTERACTION OF SUPRATHERMAL IONS WITH LIGHTNING-GENERATED ION CYCLOTRON WAVES Kuzichev I.V., Shklyar D.R. ....................................................................... 73 DEPENDENCE OF REGRESSION COEFFICIENT BETWEEN INTERPLANETARY AND MAGNETOSPHERIC FIELD BY ON DATABASE SELECTION CRITERIA Lukin A.S., Petrukovich A.A. ..................................................................... 75 IONOSPHERIC RESPONSE ON SPACE WEATHER EVENTS ON AN EXAMPLE OF DISTURBANCE OF NOVEMBER 6TH 2001 Maltseva O.A., Sergeeva M.A. ................................................................... 76 MODELING AND ANALYSIS OF COSMIC RAY VARIATIONS DURING PERIODS OF HELIOSPHERIC DISTURBANCES Mandrikova O.V., Zalyaev T.L. .................................................................. 77 ANALYSIS OF IONOSPHERIC PARAMETERS AND DETECTION OF ANOMALIES DURING IONOSPHERIC STORMS Mandrikova O.V., Fetisova (Glushkova) N.V., Polozov Yu.A. ................... 78 COMPARATIVE ANALYSIS OF THE QUALITY OF PREDICTION FOR FLUENCES OF RELATIVISTIC ELECTRONS OF THE OUTER RADIATION BELT OF THE EARTH AT DIFFERENT PHASES OF THE SOLAR ACTIVITY CYCLE Myagkova I.N., Dolenko S.A. .................................................................... 79 MONITORING OF PLANETARY PERTURBATIONS IN THE D - REGION OF THE IONOSPHERE BY RADIO OCCULTATION METHOD Nagorskiy P.M., Lemeshko E.Yu. ............................................................... 80 COMPARATIVE ANALYSIS OF THE LONG-PERIOD VARIATIONS OF IONIZING RADIATION AND ATMOSPHERIC ELECTRICAL QUANTITIES Nagorskiy P.M., Pustovalov K.N., Smirnov S.V., Yakovleva V.S. ............. 81 NUMERICAL UPPER ATMOSPHERE MODEL (UAM) - HISTORY, CURRENT STATE, PERSPECTIVES Namgaladze A.A. ........................................................................................ 82
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LOCALIZATION OF IONOSPHERIC PC4 SOURCES AND PROTON EMISSIONS DURING MAGNETIC PULSATIONS PC1 TYPE OF PEARLS INTENSIFICATIONS Petlenko A.V. .............................................................................................. 83 MULTIPOINT STUDIES OF 2D MAGNETOTAIL CURRENT SHEET Petrukovich A.A., Artemyev A.V., Zelenyi L.M., Vasko I.Y., Nakamura R.84 CHARACTERING THE GEOMAGNETIC FIELD VARIABILITY FOR THE STUDY OF MAGNETIC STORM IMPACT ON ELECTRIC POWER LINES Pilipenko V.A., Belakhovsky V.B., Sakharov Ya.A. ................................... 85 SIMULTANEOUS OBSERVATIONS OF THE IAR EMISSIONS ALONG A MERIDIAN Polyushkina T.N., Pashinin A.Yu., Rakhmatulin R.A., Tsegmed B., Potapov A.S. ............................................................................................................. 86 THE QUASI-BIENNIAL CYCLE OF SOLAR ACTIVITY AND DYNAMO THEORY Popova E.P., Yukhina N.A. ......................................................................... 87 COMPARISON OF EMIC WAVE OBSERVATIONS IN THE NEAR-EQUATORIAL REGION OF THE MAGNETOSPHERE AND PRECIPITATION OF ENERGETIC PROTONS AT LOW ALTITUDES Popova T.A., Yahnin A.G., Demekhov A.G. ............................................... 88 THIN STRUCTURE OF THE CIR SHEAR ZONE Potapov A.S., Ryzhakova L.V. .................................................................... 89 NARROW-BAND EMISSION WITH VARYING FREQUENCY FROM 0.5 UP TO 3.5 HZ IN THE BACKGROUND OF THE MAIN PHASE OF THE 17 MARCH 2013 MAGNETIC STORM Potapov A.S., Dovbnya B.V., Baishev D.G., Polyushkina T.N., Rakhmatulin R.A. ............................................................................................................. 90 THE UPWARD TREND IN GEOMAGNETIC STORM OCCURENCES DURING THE 20TH CENTURY Ptitsyna N.G., Soldatov V.A., Sokolov S.N., Tyasto M.I. ........................... 91 THE 22-YEAR CYCLE OF AURORA BOREALIS EVENTS IN THE 19TH CENTURY Ptitsyna N.G., Tyasto M.I., Khrapov B.A. .................................................. 92 HISTORIC AURORA BOREALIS OBSERVED IN ITALY AND RELATED SOLAR AND GEOMAGNETIC ACTIVITY Ptitsyna N.G., Altamore A........................................................................... 93
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IMPACT OF THE INTERPLANETARY MAGNETIC FIELD ON FLOW AHEAD OF THE EARTH'S MAGNETOSPHERE ON IMPINGEMENT OF A SOLAR WIND DISCONTINUITY Pushkar E.A. ............................................................................................... 94 CAN MHD MODELS DESCRIBE MAGNETOSPHERIC CONFIGURATION AND DYNAMICS REASONABLY WELL? Samsonov A.A. ........................................................................................... 95 PREDICTION OF MAGNETOSPHERIC EXPANSION DURING RADIAL IMF INTERVALS USING GLOBAL MHD MODEL Samsonov A.A., Sibeck D.G., Nemecek Z., Safrankova J. ......................... 96 PROCESSES AT THE BOW SHOCK AND AT THE TRANSITION LAYER Sedykh P.A.................................................................................................. 97 MAGNETOSPHERE-IONOSPHERE COUPLING DURING A SUBSTORM Sedykh P.A.................................................................................................. 98 FEATURES OF THE MOTION OF THE NORTH MAGNETIC POLE Semakov N.N., Grigorevsky A.V., Kovalev A.A., Fedotova O.I., Pavlov A.F. ............................................................................................................. 99 GLOBAL DISTRIBUTION OF ENERGETIC PROTON PRECIPITATION EQUATORWARD OF THE ISOTROPY BOUNDARY Semenova N.V., Popova T.A., Yahnina T.A., Yahnin A.G. ....................... 101 FORECASTING CONDITIONS OF THE EARTH'S OUTER RADIATION BELT ACCORDING TO SPACE EXPERIMENTS Sentemova N.S., Myagkova I.N., Dolenko S.A., Shirokyj V.R. ............... 102 EFFECT OF IMF TURBULENCE IN THE VICINITY OF INTERPLANETARY SHOCKS ON GEOMAGNETIC STORMS AND SUBSTORMS GENERATION Shadrina L.P., Starodubtsev S.A. .............................................................. 103 PHASE SHIFT BETWEEN SOLAR HEMISPHERES IN THE ACTIVITY CYCLE Shibalova A.S., Obridko V.N., Sokoloff D.D. .......................................... 104 MODEL OF SUBPROTON-SCALE MAGNETIC HOLES Shustov P.I., Artemyev A.V., Vasko I.Y, Yushkov E.V. ............................. 105 THE ANALYTICAL DESCRIPTION OF THE EARTH’S RING CURRENT PROTON FLUX FOR THE 90° PITCH ANGLE Smolin S.V. ............................................................................................... 106
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THREE-DIMENSIONAL MODEL OF THE EVOLUTION OF THE EARTH'S RING CURRENT PROTONS DURING THE MAGNETIC STORM Smolin S.V. ............................................................................................... 106 SPECIALIZED AUROMAG DATABASE OF HISTORICAL GEOMAGNETIC AND AURORAL ACTIVITY Soldatov V.A., Sokolov S.N., Ptitsyna N.G., Tyasto M.I. ......................... 107 UPFLOW IONOSPHERIC PLASMA IN THE POLARIZATION JET REGION Stepanov A.E., Khalipov V.L., Kotova G.A., Kobyakova S.E., Bogdanov V.V., Kaisin А.V. ....................................................................................... 108 SOLAR ACTIVITY AND VARIATIONS IN RADIO FREQUENCY PULSE NUMBER OF LIGHTNING DISCHARGES RECORDED IN YAKUTSK IN SUMMER 2001-2015 Tarabukina L.D., Kozlov V.I., Korsakov A.A. .......................................... 109 PHYSICAL NATURE OF THE THERMO-ANOMALOUS LAYER DIAGNOSED BY THE EISCAT RADAR WITHIN THE DUSTED NIGHTSIDE AURORAL LOW IONOSPHERE Timofeev E.E., Shalimov S.L., Vallinkoski M.K...................................... 110 THE MAGNETOSPHERIC "IDENTIKIT": WHAT WE KNEW AND LEARNED OVER FOUR SOLAR CYCLES WORTH OF SPACECRAFT MEASUREMENTS? Tsyganenko N.A. ...................................................................................... 112 THE STRATOSPHERIC POLAR VORTEX AS A CONTROLLING FACTOR OF COSMIC RAY INFLUENCE ON CYCLONIC PROCESSES AND LOW CLOUD ANOMALIES AT MIDDLE LATITUDES Veretenenko S.V., Ogurtsov M.G. ............................................................. 113 KINETIC MODELS OF MAGNETIC FLUX ROPES OBSERVED IN THE EARTH MAGNETOSPHERE Vinogradov A.A., Vasko I.Y., Artemyev A.V., Yushkov E.V., Petrukovich A.A., Zelenyi L.M. ................................................................................... 114 FORMATION OF THE TWO-DIMENSIONAL ELECTRIC FIELD STRUCTURES IN THE AURORAL CAVITY Volkov M.A. ............................................................................................. 115 CHARACTERISTICS AND CONDITIONS FOR GENERATION OF ISOLATED SUBSTORMS Yagodkina O.I., Vorobjev V.G., Zverev V.L. ............................................. 115
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ON THE ROLE OF EMIC WAVES IN PRODUCTION OF RELATIVISTIC ELECTRON PRECIPITATION Yahnin A.G., Yahnina T.A., Raita T., Manninen J. .................................... 116 COLD PLASMA DENSITY IN THE REGIONS OF THE REP GENERATION Yahnina T.A., Yahnin A.G. ........................................................................ 117 ELECTRON ANISOTROPY AND THE DAWN-DUSK MAGNETIC FIELD IN THE EARTH MAGNETOTAIL Yushkov E.V., Artemyev A.V., Petrukovich A.A., Nakamura R. .............. 118 ANISOTROPY AND ION ACCELERATION IN RECONNECTION EXHAUST Zaitsev I.V., Divin A.V., Semenov V.S. .................................................... 119 ELECTROMAGNETIC ULF WAVE ENERGY LEAKAGE THROUGH THE IONOSPHERE AS OBSERVED BY LOW-ORBITING SATELLITES SWARM Zelikson I.S., Pilipenko V.A. .................................................................... 119 ON THE SPECIFIC PROPERTIES OF DIURNAL VARIATION OF THE PC1 GEOMAGNETIC PULSATION AT MIDDLE LATITUDE Zotov O.D. ................................................................................................ 120 P. PALEOMAGNETISM AND ROCK MAGNETISM ........................... 121 PRELIMINARY DATA ON THE MAGNETIC PROPERTIES OF LAKE RUBSKOE SEDIMENTS (IVANOVO REGION) Akhmerov R.D., Nurgaliev D.K., Kosareva L.R., Kuzina D.M., Krylov P.S., Antonenko V.V., Yusupova A.R. ....................................................... 121 NEW ARCHEOINTENSITY DATA FROM LATE NEOLITHIC HALAFIAN SETTLEMENT YARIM TEPE 2 (NORTHERN IRAQ): GEOMAGNETIC AND ARCHEOLOGICAL IMPLICATIONS Akimova S.V., Gallet Y., Amirov S.N....................................................... 122 MODELING OF THE EXCHANGE BIAS OF THE HYSTERESIS LOOPS IN LOW-TEMPERATURE MAGNETITE Anisimov S.V., Afremov L.L., Iliushin I.G. .............................................. 123 ON THE ORIGIN OF L-SHAPED ARAI-NAGATA DIAGRAMS Aphinogenova N.A., Shcherbakov V.P., Tsel'movich V.A., Smirnov M.A., Kozmina L.V. ............................................................................................ 124
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ON THE POSSIBLE SELF-REVERSAL OF MAGNETIZATION OF TITANOMAGNETITE Belokon V.I., Dyachenko O.I. ................................................................... 125 HOW TO DISCRIMINATE BETWEEN THERMAL AND MECHANICAL EFFECTS OF SHOCK ON THE ROCK MAGNETIC PROPERTIES OF BASALT AND DIABASE SPHERICALLY SHOCKED UP TO ~10-160 GPA Bezaeva N.S., Swanson-Hysell N.L., Tikoo S.M., Kars M., Egli R., Badyukov D.D., Chareev D.A., Fairchild L.M. ........................................ 126 SOME PROBLEMS OF MAGNETIC AND PALEOMAGNETIC STUDY OF THE PLEISTOCENE (THE CASE OF THE CHINESE LOESS PLATEAU SEDIMENTS) Bol’shakov V.A. ........................................................................................ 128 THE PROBLEM OF IDENTIFICATION OF HOLOCENE TEPHRA BY THERMOMAGNETIC METHOD Burnatny S.S., Naumov A.N., Tsygankova V.I., Minyuk P.S. .................. 129 CURRENT MODEL OF THE MAIN GEOMAGNETIC FIELD: POSSIBILITIES AND RESTRICTIONS Demina I.M., Gorshkova N.V., Farafonova Yu.G. .................................... 130 MAGNETIC FIELD OF THE VOLUME CURRENT SYSTEMS ON THE EARTH'S SURFACE AND NEAR THE CORE-MANTLE BOUNDARY Demina I.M., Gorshkova N.V., Soldatov V.A. .......................................... 131 PALEOMAGNETISM OF THE SOUTHERN TIEN SHAN UPPER PALEOZOIC FORMAITIONS Dvorova A.V. ............................................................................................ 132 MAGNETIC PROPERTIES OF ROCKS COLLECTED FROM THE SEABED OF THE MENDELEEV RISE (ARCTIC OCEAN): HIGH- AND LOW-TEMPERATURE BEHAVIOUR Elkina D.V., Piskarev A.L. ........................................................................ 133 PALEOMAGNETISM OF LATE PALEOZOIC AND MESOZOIC VOLCANIC ROCKS FROM SOUTH TRANSBAIKALIA: NEW DATA Fedyukin I.V. ............................................................................................ 134 NEW DATA ON MAGNETOSTRATIGRAPHY OF PERMIAN-TRIASSIC STRATA FROM THE CENTRAL EUROPEAN BASIN (GERMANY) Fetisova A.M., Veselovskiy R.V., Scholze F. ............................................ 135
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CENOZOIC MAGNETOSTRATIGRAPHIC SECTION OF THE ISHIM PLAIN (WEST SIBERIAN PLATE) Gnibidenko Z.N., Kuz'mina O.B., Khazin L.B., Khazina I.V. .................. 136 DEVONIAN AND LOWER CARBONIFEROUS PALEOMAGNETISM IN THE MAGNITOGORSK ZONE OF THE SOUTH URALS: PRELIMINARY RESULTS Golovanova I.V., Danukalov K.N., Matrosov V.Yu., Khidiyatov M.M., Bazhenov M.L. ......................................................................................... 138 PALEOMAGNETISM OF ORDOVICIAN-SILURIAN VOLCANIC ROCKS ON THE WESTERN SLOPE OF THE SOUTH URALS: PRELIMINARY RESULTS Golovanova I.V., Danukalov K.N., Bazhenov M.L. ................................ 139 TO THE ASSESSMENT OF THE IMPACT OF PROCESS OF SINGLE-PHASE OXIDATION AND SUBSEQUENT DECOMPOSITION OF TITANOMAGNETITES ON THE RESULTS OF PALAEOINTENSITY DETERMINATION BY THE THELLIER METHOD Gribov S.K., Dolotov A.V. ........................................................................ 140 RE PALEOMAGNETIC STUDIES OF CARBONIFEROUS SEDIMENTS FROM OLD COLLECTIONS (RUSSIAN PLATFORM) Iosifidi A.G., Mikhailova V.A. .................................................................. 141 STUDY OF SHORT MARINE MAGNETIC ANOMALIES Ivanov S.A., Merkur'ev S.A. .................................................................... 143 APPLICATION OF PALEOMAGNETIC METHOD FOR STUDIES OF ROCKS AND PETROMAGNETIC MAP COMPILATION (ARMENIA) Karakhanyan A.K., Minasyan J.O. ........................................................... 144 ABOUT THE NATURE OF STRIPE MAGNETIC ANOMALIES IN SUBDUCTION ZONES Karimov F.H. ............................................................................................ 145 SLAVIN YAR KEY SECTION – NEW ROCK-MAGNETIC EVIDENCE OF VOLCANIC EVENTS IN TRANSBAIKALIA Kazansky A.Yu., Matasova G., Shchetnikov A.A., Filinov I.A., Chegis V.V.146 MAGNETIC ENHANCEMENT MECHANISM IN LATE QUATERNARY PALEOSOL FROM DAGESTAN Kazansky A.Yu., Rybalko A.A., Matasova G.G., Kosterov A.A. .............. 147
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TWO TYPES OF IMPACT MELTS WITH CONTRASTING MAGNETIC MINERALOGY FROM JÄNISJÄRVI IMPACT STRUCTURE, RUSSIAN KARELIA Kharitonskii P.V., Kosterov A.A., Sergienko E.S. .................................... 148 MAGNETIC PROPERTIES AND FEATURES OF A MICROSTRUCTURE OF BARK OF MELTING OF THE CHELYABINSK METEORITE Korzinova A.S. ......................................................................................... 149 MAGNETIC PROPERTIES AND MICROSTRUCTURE FEATURES OF THE FUSION CRUST OF THE CHELYABINSK METEORITE Korzinova A.S., Tselmovich V.A. ............................................................. 150 THE ENVIRONMENTAL HISTORY OF LAKE HOVSGUL, MONGOLIA, BASED ON A PHYSICAL INTERPRETATION OF REMANENT MAGNETIZATION ENDMEMBERS Kosareva L.R., Shcherbakov V.P., Nourgaliev D.K., Fabian K. ............... 151 EVALUATION OF STABILITY OF PALEOMAGNETIC SIGNAL FROM ROCKS WEATHERED IN CONDITIONS OF WAVE-CUT ZONE Kulakova E.P., Veselovskiy R.V. .............................................................. 152 ANISOTROPY OF MAGNETIC SUSCEPTIBILITY OF THE DOLERITE SILLS FROM THE ANGARA-TASEEVA DEPRESSION (THE SIBERIAN PLATFORM) AND ITS IMPLICATION FOR THE MAGMA EMPLACEMENT RECONSTRUCTION Latyshev A.V., Ulyahina P.S., Veselovskiy R.V., Mirsayanova E.M. ....... 153 THE MODERN MAGNETIC MEASUREMENT EQUIPMENT FOR ARCHEOMAGNETIC RESEARCH Legoff M. .................................................................................................. 154 MORE STABLE YET BIMODAL GEODYNAMO DURING THE CRETACEOUS SUPERCHRON? Lhuillier F., Gilder S.A., Wack M., He K., Petersen N., Singer B.S., Jicha B.R., Schaen A.J., Colon D....................................................................... 155 RELATIONSHIP BETWEEN ROCK-MAGNETIC AND GRAIN SIZE DATA FROM EARLY QUATERNARY SECTION "TOGAY" (OLKHON ISLAND, BAIKAL LAKE) Matasova G.G., Kazansky A.Yu., Shchetnikov A.A., Filinov I.A. ............ 156 GEOMAGNETIC FIELD INTENSITY VARIATIONS AROUND TOWN TAMAN IN THE SECOND HALF OF THE FIRST MILLENNIUM BC
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Nachasova I.E., Pilipenko O.V., Markov G.P. ........................................... 157 MAGNETIC PROPERTIES OF ROCKS OF THE SOLAR PROSPECTIVE AREA OF THE SUGOYSKY FOLDED ZONE NORTHEAST OF RUSSIA Naumov A.N., Burnatny S.S., Ivanov Yu.Yu. ........................................... 158 A PRELIMINARY PALEOMAGNETIC, ROCK MAGNETIC, LOW FIELD AMS AND PETROLOGICAL STUDIES OF THE MAFIC DYKES FROM THE NORTHERN PART OF SINGHBHUM CRATON, EASTERN INDIA Nishad R.K., Pradhan S.K., Patil S.K., Sinha A.K. .................................. 159 THE NEW PALEOMAGNETIC DATA FROM UPPER RIPHEAN KHAYPAKH FORMATION (OLENEK UPLIFT) Pasenko A.M. ............................................................................................ 160 NEW PALEOMAGNETIC DATA FROM THE NORTHERN PART OF THE UCHUR-MAYA REGION (EASTERN MARGIN OF THE SIBERIAN PLATFORM) FURTHER SUPPORTS THE COEXISTENCE OF SIBERIA AND LAURENTIA WITHIN ONE SUPERCONTINENT AND RAPID APPARENT POLAR WANDER DURING THE LAST 100 MILLIONS YEARS OF THE MESOPROTEROZOIC Pavlov V.E., Novikova A.S. ...................................................................... 162 DISTRIBUTION OF METALLIC IRON IN PLANETS Pechersky D.M., Kuzina D.M. ................................................................. 163 NEW ARCHEOMAGNETIC RESEARCH OF POTTERY FROM NEOLITHIC SETTLEMENT SAHTYSH-I (IVANOVO REGION, RUSSIA) C. 5000-2000 BC Pilipenko O.V., Nachasova I.E., Markov G.P., Gribov S.K., Tsetlin U.B. 164 PALEOMAGNETIC STUDIES OF THE REFERENCE SECTION OF THE LOWER CARBONIFEROUS OF MSTA RIVER Popov V.V., Sergienko E.S., Iosifidi A.G., Mikhailova V.A...................... 165 PERMIAN-TRASSIC REMAGNETIZATION OF BALTURINO FM.(LOWER SILURIAN, PRESAYANS): POSSIBLE IMPLICATIONS ON THE DURATION OF TRAP EMPLACEMENT Powerman V.I., Shatsillo A.V., Latyshev A.V. .......................................... 166 EARLY SOLAR SYSTEM, PALEOMAGNETIC FIELD AND THE BIOSPHERE: CURRENT ISSUES Ragulskaya M.V., Obridko V.N., Hramova E.G. ....................................... 167
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NEW ARCHEOINTENSITY DATA FROM NORTH WESTERN AND CENTRAL RUSSIA BETWEEN 12 AND 19 CENTURY AD Salnaia N., Gallet Y., Antipov I., Genevey A. ........................................... 168 EXTREMELY WEAK PALAEOINTENSITY RESULTS FROM THE MINUSA BASIN AND KOLA PENINSULA: WAS THE DEVONIAN FIELD SPATIALLY COMPLEX? Shcherbakova V.V., Biggin A., Shatsillo A.V., Veselovskiy R.V., Hawkins L., Shcherbakov V.P., Zhidkov G.V. .......................................................... 170 CAUSES OF FALSE PALEODIRECTION DETERMINATIONS OBTAINED ON SIBERIAN TRAP AND STEENS MOUNTAIN ROCKS FROM CONVENTIONAL STEPWISE THERMAL DEMAGNETIZATION Shcherbakov V.P., Latyshev A.V., Veselovskiy R.V. ................................ 171 DETERMINATION OF HYSTERESIS LOOP PARAMETERS USING COMBINATION OF LINEAR AND SPLINE INTERPOLATIONS Solyanikov Ya.L., Malakhov M.I. ............................................................ 172 HYDROMAGNETIC SOURCES OF FOUR CENTURIES OBSERVED MULTI-POLES IN THE EARTH’S CORE Starchenko S.V., Yakovleva S.V. .............................................................. 173 DEDUCING GEODYNAMO AND PLANETARY DYNAMO PARAMETERS FROM SCALING LAWS, DIRECT OBSERVATIONS AND PALEOMAGNETIC RECONSTRUCTIONS Starchenko S.V. ......................................................................................... 174 MAGNETIC PROPERTIES OF IMPACT MELTS FROM THE ZHAMANSHIN ASTROBLEME REFLECTING THEIR FORMATION IN EXTREME CONDITIONS Starunov V.A., Kosterov V.A., Sergienko E.S., Kharitonskii P.V. ............ 175 POSSIBILITIES OF PEAT FOR DIAGNOSTICS OF THE NATURE OF CATASTROPHE EVENTS ACCORDING TO MAGNETIC AND MICROPROBE DATA Tselmovich V.A., Kurazhkovskii A.Yu., Kazansky A.Yu., Shchetnikov A.A., Blyakharchuk T.A., Amelin I.I. ...................................................... 177 AEROMAGNETIC SURVEYS USING UNMANNED AERIAL VEHICLES IN FOREIGN COUNTRIES AND IN RUSSIA Tsirel V.S., Semenova M.P., Titova A.V. .................................................. 178 WHEN SEDIMENTS FAIL TO RECORD GEOMAGNETIC FEATURES
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Valet J.P., Meynadier L., Simon Q., Thouveny N. .................................... 179 NEW PALEOMAGNETIC DATA FROM THE EMEISHAN TRAPS AND PANZHIHUA LAYERED INTRUSION, SW CHINA Veselovskiy R.V., Krivolutskaya N.A., Song X.-Y., Chen L.-M., Yu S.-Y., Smolkin V.F., Gongalskiy B.I. .................................................................. 180 NEW MIDDLE-LATE DEVONIAN PALEOMAGNETIC POLE FOR EAST EUROPEAN PLATFORM AND AR/AR AGES FROM THE KOLA ALKALINE MAGMATIC PROVINCE Veselovskiy R.V., Kulakova E.P. .............................................................. 181 THE LATE ORDOVICIAN-SILURIAN REVERSAL DEPOSITS OF THE WESTERN SLOPE OF THE SOUTHERN URALS Vinogradov E.V......................................................................................... 182 PALEOMAGNETISM OF THE EARLY PROTEROZOIC COMPLEXES OF THE OLEKMA BLOCK OF THE SIBERIAN CRATON Vodovozov V.Yu., Zverev A.R., Filev E.A. .............................................. 183 EVALUATION OF GEODYNAMO PARAMETERS AND OLDER FIELDS FROM DIPOLE AND QUADRUPOLE OBSERVED SINCE 1840 Yakovleva S.V., Starchenko S.V., Ivanov V.V .......................................... 184 PALAEOINTENSITY DETERMINATIONS ON ROCKS FROM PALEOPROTEROZOIC DYKES FROM THE KOLA PENINSULA (RUSSIA) Zhidkov G.V., Shcherbakova V.V., Lubnina N.V., Shcherbakov V.P., Smirnov M.A. ........................................................................................... 185 EARLY PROTEROZOIC NRM COMPONENTS OF AKITKAN GROUP OF MINYA RIVER - NEW TWO PALEOMGNETIC POLES Zverev A.R., Vodovozov V.U. .................................................................. 186 EG. EXPLORATION GEOPHYSICS AND EARTH CONDUCTIVITY 188 COMPARISION OF THE AMPLITUDE AND THE PHASE GEOELECTRICAL MODELS OF THE MT PROFILES IN BELARUS Astapenko V. ............................................................................................. 188 PROSPECTS OF USING THE NUMERICAL MODELLING IN CONJUNCTION WITH THE GROUND PENETRATING RADAR (GPR) TO STUDY ICE WEDGES Bricheva S.S., Stanilovskaya Ju.V. ........................................................... 189
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COMPLEX ALGORITHM FOR NEURAL NETWORK SOLUTION OF THE INVERSE PROBLEM OF MAGNETOTELLURIC SOUNDING BASED ON DATA CLASSIFICATION Dolenko S.A., Isaev I.V., Obornev I.E., Obornev E.A., Shimelevich M.I.190 ON THE CONVECTION WITHIN THE MANTLE WEDGE BENEATH THE TIMAN-PECHORA PLATE AS A MECHANISM OF TRANSPORT OF HYDROCARBONS AT PALEOZOIC Gavrilov S.V., Kharitonov A.L. ................................................................ 191 APPLICATION OF CLASSIFICATION ALGORITHMS FOR SELECTION OF THE OPTIMAL PARAMETRIZATION SHEME IN THE INVERSE PROBLEM OF MAGNETOTELLURIC SOUNDING Isaev I.V., Obornev I.E., Obornev E.A., Shimelevich M.I., Dolenko S.A.192 SPECTRAL ANALYSIS OF THE GEOBIOCHRONOLOGICAL CYCLES SHOWN IN THE COURSE OF EVOLUTION OF THE EARTH AND THEIR COMMUNICATION WITH PHYSICAL FIELDS OF SPACE Kharitonov A.L. ........................................................................................ 193 MULTI-ELECTRODE ELECTRICAL PROFILING CARRIED ON UNDER THE LADOGA ELECTRICAL CONDUCTIVITY ANOMALY IN COMPLEX WITH MT-AMT SOUNDINGS ("LADOGA-2015" EXPERIMENT) Kolesnikov V.E., Zhamaletdinov A.A., Shevtsov A.N., Skorokhodov A.A., Ryazantsev P.A., Nilov M.Yu. .................................................................. 195 MEASUREMENTS OF ELECTRICAL PROPERTIES OF ROCKS WITHIN A WIDE FREQUENCY RANGE USING A FOUR-ELECTRODE SYSTEM Linok A.V. ................................................................................................. 196 DEEP STRUCTURE OF TOLBACHIK FISSURE ERUPTION BY MT SOUNDING Moroz Yu.F., Loginov V.A. ....................................................................... 197 THE EARTH’S CRUST AND UPPER MANTLE OF KAMCHATKA FROM GEOPHYSICAL DATE Moroz Yu.F., Gontovaya L.I. .................................................................... 198 MAGNETOTELLURIC SOUNDING IN 3D-CASE (NUMERICAL SIMULATION) Plotkin V.V., Gubin D.I. ............................................................................ 199
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THE MULTIPATH FREQUENCY SOUNDING ONTO KOVDOR-YONA AREA OF THE KOLA PENINSULA (EXPERIMENT "KOVDOR-2015") Shevtsov A.N., Kolobov V.V., Zhamaletdinov A.A., Kolesnikov V.E., Skorokhodov A.A., Ryazantsev P.A., Birulia M.A., Ivonin V.A. ............. 200 ANISOTROPIC LAYER’S MODELING AT DECIDING OF TWO-DIMENSIONAL MAGNETOTELLURIC PROBLEMS Skorokhodov A.A., Vardanjants I.L. ......................................................... 201 GPR STUDY OF THERMOCLINE IN THE FRESH WATER BASINS Titov A.V., Bobrov N.Yu., Krylov S.S. ..................................................... 202 THE GEOTHERMAL RESOURCES OF THE TERRITORY OF ARMENIA Vardanyan K.S. ......................................................................................... 203 S. SEISMOLOGY .................................................................................... 205 INVESTIGATION OF MASS TRANSPORT IN THE EARTH'S SYSTEM WITH SATELLITE GRAVIMETRY AND OTHER REMOTE SENSING TECHNIQUES Ditmar P. ................................................................................................... 205 COMPARISON OF THE RESULTS OF SEISMIC METHODS T0′ AND FORWARD RAY TRACING ON TRAINING PROFILE NEAR NOVOSIBIRSK Eliseev A.A. .............................................................................................. 206 THE USE OF PARALLEL PROGRAMMING IN PROBLEMS OF EARTHQUAKE PARAMETERS DETERMINATION Fomochkina A., Bukchin B. ..................................................................... 207 REVEALING THE ANOMALOUS HIGH-VELOCITY BODY IN THE CRUST OF CRIMEAN MOUNTAINS BY LOCAL SEISMIC TOMOGRAPHY Gobarenko V.S., Yegorova T.P. ................................................................. 208 AN ELECTRONIC FREEZEMETER Gravirov V.V., Kislov K.V. ....................................................................... 209 DERIVATION AND GENERALIZATION OF THE OMORY LAW Guglielmi A.V., Zotov O.D. ...................................................................... 210
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THE DECADE OF CONTINUOUS SEISMOLOGICAL OBSERVATIONS ON VALAAM ISLAND Karpinsky V.V. .......................................................................................... 211 ON THE PROBLEM OF THE APPLICATION OF DEEP NEURAL NETWORKS IN SEISMOLOGY Kislov K.V., Gravirov V.V. ....................................................................... 211 SURFACE WAVE TOMOGRAPHY OF THE CENTRAL EUROPE Lyskova E.L., Koroleva T.Yu., Yanovskaya T.B. ...................................... 212 DEPENDENCE OF TRAVEL-TIME TOMOGRAPHY SOLUTION ON A STARTING MODEL Medvedev S.V., Yanovskaya T.B. ............................................................. 213 SEISMIC POTENTIAL OF THE BALTIC SHIELD AND RUSSIAN PLATE COUPLING ZONE ACCORDING TO GNSS DATA Mokhnatkin A., Assinovskaya B., Gorshkov V., Smirnov S., Scherbakova N. .............................................................................................................. 214 APPLICATION A DOUBLE-DIFFERENCE EARTHQUAKE LOCATION ALGORITHM TO MICROSEISMIC MONITORING DATA FROM PYHÄSALMI MINE, FINLAND Nevalainen J., Usoltseva O., Kozlovskaya E. ........................................... 215 THE LONG-TERM EARTH’S DEFORMATIONS FROM SEISMOGRAVIMETER DATA AT SAINT-PETERSBURG Petrova L.N. .............................................................................................. 216 CONCERNING THE ORIGIN OF THE RARE FEBRUARY 1, 2011, MW=4.7 EARTHQUAKE IN WESTERN TRANSBAIKALIA Seredkina A.I. ........................................................................................... 218 DEEP VELOCITY STRUCTURE OF THE UPPER MANTLE IN ASIA BASED ON DISPERSION OF RAYLEIGH AND LOVE WAVES Seredkina A.I., Kozhevnikov V.M., Solovey O.A. ................................... 219 APPLICATION OF A SIMULATED ANNEALING METHOD FOR DETECTION AND MEASUREMENT OF PARAMETERS OF PKIIKP WAVES Usoltseva O.A., Ovtchinnikov V.M. ......................................................... 220 FEATURES AND GENERATION MECHANISMS OF SUBVERTICAL CLUSTERS OF EARTHQUAKE FOCI Zakharov V.S. ........................................................................................... 221
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SEMP. SEISMO-ELECTROMAGNETIC PHENOMENA ..................... 222 VARIATIONS OF IMPULSIVE NATURAL VLF SIGNALS PASSING OVER EPICENTERS OF EARTHQUAKES BY OBSERVATIONS IN YAKUTSK Argunov V.V. ............................................................................................ 222 THE MAGNETOSONIC WAVES IN THE MID-LATITUDE IONOSPHERE APPEARING WITHIN PREPARATION PHASE OF STRONG EARTHQUAKES Barkhatova O.M., Barkhatov N.A., Kosolapova N.V., Yagodkina O.I. ... 223 ANALYSIS OF A FEW MATHEMATICAL MODELS OF QUASI-STATIONARY ELECTRIC FIELDS PENETRATION TO THE IONOSPHERE THROUGH THE EARTH’S ATMOSPHERE Denisenko V.V., Kitaev A.V., Boudjada M., Lammer H. .......................... 224 MODELING OF SEISMIC-ELECTROMAGNETIC PROCESSES IN HETEROGENEOUS MEDIA WITH HIERARCHIC CONDUCTIVE, MAGNETIC, ELASTIC AND DENSE INCLUSIONS Hachay O.A., Khachay O.Yu., Khachay A.Yu.......................................... 225 RESEARCH OF LITHOSPHERE-IONOSPHERE RELATIONSHIPS BY OBSERVATIONS RADIO SIGNAL AMPLITUDE VARIATIONS IN THE RANGE OF 16-60 KHZ, REGISTERED IN TIKSI Karimov R.R., Argunov V.V., Korsakov A.A. .......................................... 226 INVESTIGATION OF THE MAGNETIC FIELD DISTURBANCES FROM THE CATASTROPHIC TSUNAMI OF 11.03.2011 IN JAPAN Kopytenko Yu.A., Ismagilov V.S., Hayakawa M...................................... 227 THE RESULTS OF MONITORING THE ELECTRICAL CONDUCTIVITY OF THE LITHOSPHERE IN SUBDUCTION ZONE OF KAMCHATKA Moroz Yu.F., Smirnov S.E. ....................................................................... 228 FEATURES OF BEHAVIOR OF THE SECULAR VARIATION OF THE VERTICAL GEOMAGNETIC FIELD IN KAMCHATKA Moroz Yu.F., Smirnov S.E. ....................................................................... 229 ON DELIVERY OF THE SEISMOGENIC ELECTRICITY TO THE IONOSPHERE Namgaladze A.A., Karpov M.I. ................................................................ 230
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ELECTRICAL TRIGGERING OF EARTHQUAKES: INSIGHT FROM LABORATORY EXPERIMENTS Novikov V.A., Ruzhin Yu.Ya., Okunev V.I., Klyuchkin V.N., Shen X., Liu J. ................................................................................................................ 231 DETECTION OF VLF⁄LF SIGNALS SENSITIVITY TO THE EFFECT OF SEISMIC AND GEOMAGNETIC ACTIVITY ACCORDING TO THE MONITORING IN THE KURIL-KAMCHATKA REGION Popova I.V., Rozhnoi A.A., Solovieva M.S., Levin B.V., Chebrov D.V... 232 SEISMOMAGNETIC EFFECT IN FAULT ZONES Riabova S.A., Spivak A.A. ....................................................................... 233 THE LOWER-IONOSPHERIC PERTURBATIONS AS A PRECURSOR TO THE NEPALESE EARTHQUAKES IN APRIL-MAY 2015 Rozhnoi A., Solovieva M., Fedun V., Srivastava A. ................................. 235 EARTHQUAKE-PRECURSORY BEHAVIOR OF THE GROUND-OBSERVED ULF EMISSIONS: EXPERIMENTAL RESULTS AND THE SOC-BASED MODELING Smirnova N.A., Troyan V.N., Kopytenko Yu.A., Uritsky V.M., Hayakawa M. .............................................................................................................. 236 THE LOWER IONOSPHERE RESPONSE DRIVEN BY THE CHAIN OF THE METEOTSUNAMIS IN THE MEDITERRANEAN SEA IN JUNE 2014 Solovieva M., Rozhnoi A., Biagi P.F., Maggipinto T., Levin B. ............... 237 INFLUENCE OF THE GALACTIC COSMIC RAY ON METEOROLOGICAL PARAMETERS IN THE STRATOSPHERE Artamonova I.,Eliseev A........................................................................... 238 LOCAL MAGNETIC FIELDS ON THE MOON AND FORMATION OF LUNAR SURFACE SWIRLS Divin A., Ahmadi T., Deca J.. ................................................................. . 239 HIGH-PERFORMANCE COMPUTING IN APPLICATION TO SIMULATIONS OF MAGNETOSPHERIC PLASMA Divin A.V.................................................................................................. 240 AUTHORS INDEX .................................................................................. 241
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STP. SOLAR-TERRESTRIAL PHYSICS
ON SOLUTION ACCURATENESS OF A SOUTHERN BOUNDARY DETERMINATION IN THE CASES OF
UREP EVENTS
Astafiev A.M., Remenets G.F.
Radio Physics Department of Saint Petersburg State University
A problem of ultra-energetic relativistic electron (about 100 MeV) precipitation at high latitudes has declared about itself due to indirect measurements in the VLF radio range (10 – 16 kHz) [1]. The corresponding theoretical analysis of VLF amplitude and phase data uses the modals of waveguide with (i) the input electric properties of ground and with (ii) an abrupt boundary in longitudinal direction of the waveguide model. The influence of these two types of model parameters on the determination accurateness of southern boundary of the URE precipitations is an object of our report. (i). The electric properties of ground in the model parts were accepted as homogeneous between the VLF sources in Aldra (North Norway), in Ragby (UK) and the receivers in Apatity (Kola peninsular, Russia). This not adequacy to the electric properties of real radio path is a source of systematic error for the result (for a value of magnetic latitude of the precipitation boundary). The above estimation of this error is illustrated below by a fragment of our output data. In every event represented below by a value of magnetic latitude two values are given: a value of latitude for the model calculations with conductivity corresponding to rock ground and a value of difference (in brackets) between the latitude values calculated for the rock electric conductivity and for the ground with ideal conductivity [2, 3]. The values of magnitudes, characterizing the southern boundaries of URE precipitations for three events are the following: 16 Apr. 1984 - 61.1° (0.6°); 23 Apr. 1986 - 62.0° (0.3°); 13 May 1987 - 59.9° (0.9°). We see that the above estimation of systematic error is not greater than an error estimation gotten earlier [2, 3].
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(ii) The latitude boundary of precipitation was defined in the calculations for a modal inhomogeneous waveguide with an abrupt boundary between two homogeneous parts. The boundary of not homogeneity is a cause of intoxication of other normal waves by a main normal wave in the waveguide. To assess the impact of these effects on the output result was solved a separate task of mode conversion at a single step height change in the earth-ionosphere VLF waveguide [4]. The evaluation showed that the contribution of mode conversion to the attenuation of VLF signal from Ragby (UK) does not exceed 1-2%. The insignificance of this radio wave propagation effect on the accurateness of southern boundary determination was estimated. Literature: 1. Remenets, G. F., Beloglazov M. I., 2013. Ultrarelativistic electrons in the near cosmos, and X-ray aurora in the middle polar atmosphere. J. Geophys. Res., Space Physics, vol. 118, pp. 6829-6838. doi: 10.1002/2013JA018822. 2. Remenets G. F., Astafiev A. M., 2015. Southern boundaries of ultraenergetic relativistic electron precipitations in several cases from 1982 - 1986 years. J. Geophys. Res., Space Physics, vol. 120(5), pp. 3318-3327. doi: 10.1002/2014JA020591. 3. Remenets G. F., Astafiev A. M., 2016. Solution uniquity of an inverse VLF problem: A case-study of the polar, ground-based, VLF radio signal disturbances caused by the ultra-energetic relativistic electron precipitations and of their southern boundaries // Advances in Space Research, vol. 58, pp. 878-889. doi: 10.1016/j/asr.2016.05.45. 4. Wait J. R., Spies K. P., 1968. On the calculation of mode conversion at a graded height change in the earth-ionosphere waveguide at VLF, Radio Sci., vol. 3, pp. 787-791.
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SUPRAMOLECULAR PHYSICS OF THE SOLAR-TROPOSPHERE LINKS: CONTROL OF THE CLOUD
COVER BY SOLAR FLARES AND MAGNETIC STORMS
Dvakyan S.V.
All-Russian Scientific Center "S.I. Vavilov State Optical Institute"
The paper concerns the influence of those basic manifestations of solar-geomagnetic activity as solar flares and geomagnetic storms upon the weather and climate. The attendant energy flows are completely absorbed in the ionosphere thus inducing the ionospheric emission in the microwave range (UHF-SHF-EHF). It is shown that this microwave emission can control the origin of optically thin cloudiness as a result of producing in the troposphere the condensational cluster haze. We have developed a new direction in the physical chemistry of the cloudy condensation - supramolecular physics which is physics outside the molecules (atomic-molecular core) when at evolution into composite formations (clusters) the environmental electromagnetic radiation takes part being absorbed by those components of molecular complex which are excited to Rydberg states and thus increasing stability of the molecular complex. During the increases of the ionospheric microwave Rydberg emission intensity (during the solar flares and geomagnetic storms), there will take place the induced population of the Rydberg levels with larger orbital quantum momentum in dissociative recombination process. As a result, the probability of the cluster ion dissociation from water vapour will decrease. So, we can assume that the microwave flux enhances concentration of water clusters in the troposphere, which leads to the formation of condensation haze and optically thin clouds, in particular in the form of a "young" cirrus clouds with the density of the particles of 10-15 cm-3. The quantitative estimations of clusterization effects during the principal magnetic storm have been made and shown a good agreement with available experimental data. The number of clusters with transition of Rydberg electron (with increase of the orbital angular momentum),
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induced by absorption of microwave quantum, during the main phase of magnetic storm is at the range from 8 to to 1.2∙104 cm-3. It is the density of those cluster ions that are experiencing decrease of collisional dissociative recombination rate. So the estimates confirm the possibility of existing slowly neutralizing and disintegrating cluster ions which density is about 10 cm-3 and much higher. From this point of view the analysis is carried out of observed variations in global cloud cover and in main meteoparameters under the impact of solar flares and magnetic storms.
SUPRAMOLECULAR PHYSICS OF THE IONOSPHERE – BIOSPHERE LINKS
Avakyan S.V.
All-Russian Scientific Center "S.I. Vavilov State Optical Institute"
The paper concerns the influence of those basic manifestations of solar-geomagnetic activity as solar flares and geomagnetic storms upon the human beings. The attendant energy flows are completely absorbed in the ionosphere thus inducing the ionospheric emission in the microwave range (UHF-SHF-EHF). It is shown that this microwave emission can control the origin of water associates formation in the human organism. The processes known in atomic physics and physics of atomic collisions are brought for explanation of clusters formation: the orbital moments of Rydberg electrons (which take part in neutralization of associates charges) grow up in the microwave field. The quantitative estimations of clusterization effects during the principal magnetic storm and solar flares have been made and shown the possibility of conversion nearly one quarter of water molecules into associates at the skin layer of human organism. It is shown here as a part of new approach to account for controlling microwave radiation parameters of the environment (including a living organism), the so called supramolecular physics which is the physics beyond the molecule (atomic-molecular core), in the evolution of which to complex forms (clusters, associates) the electromagnetic radiation of external origin participates, which is absorbed by highly excited (Rydberg) components of a molecular complex with
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increasing stability (due to the increase of the orbital angular momentum of Rydberg electron). In the context of concerned effect – the origin of “fur-coat of water associates” – an explanation is proposed of known data on rheumatoid arthritis namely worsening of clinical course in the period of solar flares as well as 5 -6 years periodicity in the increase of new cases. As a rule increasing number of new cases of rheumatoid arthritis coincides with maxima and minima of eleven year cycle of solar activity. During this cycle solar flares and magnetic storms have as a rule two maxima: the main maximum occurs near the maximum activity and the second one takes place at the activity decline. Just in these periods microwave emission from ionosphere is larger and therefore larger is a “fur-coat of water associates” which prevents phagocytes penetration through a cell membrane and recognition of arthritis effects in articular liquid by phagocytes.
GEOMAGNETIC ACTIVITY STRUCTURES OF MAGNETIC CLOUDS
Barkhatov N.A.1, Revunova E.A.2, Vinogradov A.B.1, Romanov R.V.1, Yagodkina O.I.3
1 - Nizhny Novgorod State Pedagogical University, Nizhny Novgorod, Russia
2 - Nizhny Novgorod State University of Architecture and Civil Engineering, Nizhny Novgorod, Russia
3 - Polar Geophysical Institute, Apatity, Murmansk reg., Russia
Research of geomagnetic activity of turbulent sheath for fast magnetic clouds of Solar wind, which follows after their shocks, was achieved. It is assumed that the expected geomagnetic activity is caused by magnetized Solar wind, changed as a result of exposure to a shock of the cloud, which for fast clouds ahead of wind. Borders of sheath for magnetic clouds based on the analysis of the spectra fluctuation of interplanetary magnetic field module are determined. To assess the evolution of Solar wind the time of his transfer to the magnetosphere local orientation of shock plane for 13 clouds are determined. The expected dynamics on the magnetosphere
29
boundary geoeffectiveness Bz component of the interplanetary magnetic field is calculated. Correlation analysis for AL-index dynamics with dynamics Bz component of interplanetary magnetic field is measured directly on the spacecraft WIND and calculated Bz component values is completed. It showed that the most geoeffective parameter is calculated, and the sequence is then accumulated (integrated) at 30-minute intervals of Bz component values. The corresponding values of correlation coefficient range from 0.6 to 0.96. This suggests the need to consider the evolution of the interplanetary magnetic field in the Solar wind shock magnetic cloud.
SOLAR WIND DRIVING AND FORMATION OF SUBSTORM ACTIVITY
Barkhatov N.A.1, Yagodkina O.I.2, Revunov S.E.1, Vorobjev V.G.2
1 - Nizhny Novgorod State Pedagogical University, Nizhny Novgorod, Russia
2 - Polar Geophysical Institute, Apatity, Murmansk reg., Russia
The algorithm of the reconstruction of the AL index dynamics from the parameters of the solar wind plasma and interplanetary magnetic field is developed. The integral parameter in the form of cumulative sum ∑N*V2 on the level with other geoeffective parameters of the solar wind is used for describing the process of the substorm formation. Algorithm is included in the frame of the created for reconstructing of AL indices an artificial neuron network (ANN) of the Elman’s type, which contains the additional layer of neurons, which ensures an “internal memory” about the prehistory of the restorable dynamic process. Data of 70 intervals by the duration of 8 hours, which include the periods of isolated magnetospheric substorms, were used for the instruction of ANN. The effectiveness of the proposed approach is demonstrated by the numerical neuron net experiments on the reconstruction of the AL index dynamics from the parameters of the solar wind and IMF during the periods of substorm development.
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GEOMAGNETIC AND IONOSPHERIC RESPONSE TO SSC AS OBSERVED BY THE COMPLEX OF
INSTRUMENTS
Belakhovsky V.B.1, Pilipenko V.A.2, Baddeley L.3, Sakharov Ya.A.1, Samsonov S.N.4
1 - Polar Geophysical Institute, Apatity 2 - Institute of the Physics of the Earth, Moscow
3 - UNIS, Svalbard, Norway 4 - Institute of Cosmophysical research and Aeronomy, Yakutsk
The magnetosphere and ionosphere response to the SSC event at 24 January 2012 was investigated. The analysis shows that SSC produce increase of the TEC determined by GPS receivers at Scandinavia. The response was accompanied by the increase of the electron density at the altitudes 90-200 km as seen from the VHF EISCAT radar data in Tromso. Strong increase was seen in aurora intensity by hyperspectral camera NARUSSCA of the Polar Geophysical institute in Svalbard and in CNA in mainland. GIC receiver of PGI at Kola Peninsula and Karelia also registered strong increase of the GIC and appearance of the Pc5 pulsation in GIC. Latitudinal and longitudinal magnetometer networks showed the large variety of SSC-associated ULF wave phenomena. Though most of them are more or less known for a long time, there are still no adequate theoretical interpretation of some features of these signals.
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ENERGIZATION OF THE OUTER RADIATION BELT ELECTRONS DUE TO WAVE-PARTICLE
INTERACTION
Belakhovsky V.B.1, Pilipenko V.A.2, Samsonov S.N.3
1 - Polar Geophysical Institute, Apatity 2 - Institute of the Physics of the Earth, Moscow
3 - Institute of Cosmophysical research and Aeronomy, Yakutsk
Using data from the GOES and THEMIS spacecraft we consider in detail acceleration of electrons in the magnetosphere from energy ~40 keV to energy > 2 MeV. For the description of the wave activity in the range of Pc5 pulsations (2-7 mHz) the ULF index was used. The 1.5 order of magnitude growth of the flux of MeV electrons occurs after 1-2 days after ULF index increase and growth of the seeding keV electrons. It is shown that the growth level of the MeV electrons does not depend on the intensity of geomagnetic storm and may even occur without storm. The considered events demonstrate the correlation between the increase of the solar wind velocity and growth of the relativistic electrons fluxes. It confirms the idea about the acceleration of the electrons due to the drift resonance with MHD waves in the Pc5 frequency range.
ARE THE ORBITAL INSOLATION VARIATIONS, OR CO2 OSCILLATIONS, THE MAIN DRIVERS OF THE
PLEISTOCENE GLACIAL CYCLES?
Bol'shakov V.A.
M.V. Lomonosov Moscow State University
In the review by D. Paillard (QSR, 2015), it was concluded that Milankovitch's theory cannot explain the 100 kyr periodicity of glaciations
32
within the last one million years, and that an additional factor must be responsible for global climate fluctuations. According to Paillard “geochemical” theory, changes in the CO2 content of the atmosphere are responsible. This statement radically alters the conventional viewpoint about the leading role of orbital variations on global Pleistocene climate. According to this statement CO2 variations are not the consequence of, but a cause of global climatic changes in the Pleistocene, and it is no longer necessary to employ orbital theory of paleoclimate as the explanation for glaciations. The latter conclusion is made because the changes in CO2 records have the same orbital periodicities as in other (i.e., δ18O) paleoclimatic archives. However, the new concept of the orbital theory of palaeoclimate (Bol'shakov 2003) is free of the contradictions and drawbacks of Milankovitch's theory. In this concept, mechanisms of climatic influence of particular orbital elements are presented with the provision that insolation variations for the full annual period and all latitudes must be considered. CO2 changes are regarded as a positive feedback which result from climatic fluctuations controlled by orbitally-driven variations in insolation. Meanwhile , consistency of geochemical theory can be confirmed only if the mechanism of changes in CO2 concentration should be found, which contain orbital periodicities with corresponding amplitudes. However , this problem is no less complicated than the task of creating the correct orbital theory of paleoclimate in the Pleistocene
MANIFESTATION OF METEOROLOGICAL STORM IN VARIATIONS OF THE TOTAL ELECTRON CONTENT
IN KALININGRAD REGION
Borchevkina O.P.1, Karpov I.V.1,2, Karpov A.I.1
1 - Immanuel Kant Baltic Federal University 2 - KF IZMIRAN
We present observations of atmospheric and ionospheric parameters during strong meteorological disturbances (storms) in the Kaliningrad region. The critical frequency of the F2 layer (foF2) and the total electron content
33
(TEC) were observed at the station Kaliningrad (20 °E, 54.20 °N). Atmospheric pressure and wind were taken to be the atmospheric parameters under study. The analysis of ionospheric observations has shown that during meteorological storms the amplitude of diurnal variations in TEC decreases to 50 %; and in foF2, to 15 % as compared to quiet days. The revealed changes in ionospheric conditions during meteorological storms are regularly registered and represent a characteristic feature of the meteorological effect on the ionosphere. Ionospheric disturbances develop quite rapidly, within several hours after meteorological disturbances. Gain variations of infrasonic TEC components with periods of 6-8 minutes in a storm weather day and stored in the next day It is conceivable that physical mechanisms implementing this relationship are determined by AGW propagation.
RECOGNITION OF RADIO PULSES FROM LIGHTNING STROKES
Cherneva N.V.1, Vodinchar G.M.1,2, Mochalov V.A.1, Druzhin G.I.1, Sannikov D.V.1, Malysh E.A.2,
Mochalova A.V.1
1 - Institute of Cosmophysical Research and Radiowave Propagation (IKIR FEB RAS), Paratunka (Kamchatka),
Russia 2 - Vitus Bering Kamchatka State University (KamGU Vitus
Bering), Petropavlovsk-Kamchatsky, Russia
The software-hardware complex of IKIR FEB RAS for monitoring of VLF radiation allows us to solve a number of problems associated with investigation of lightning activity, monitoring of whistler and search for their lightning sources, monitoring of volcano explosive eruptions in Kamchatka and of cyclone structures in the atmosphere over oceans. Besides the scientific aims, investigation of these tasks has a clear application component. Whistlers, as natural markers of plasmosphere state, are of great interest for space weather forecast. At the background of lightning week general activity, the direction-finder for lightning may be
34
the only mean for modern identification of volcano explosive eruptions hazardous to aviation in the condition of absence of visual controlability. There is a possibility to trace the dynamics of volcanic ash clouds and that of tropical cyclones. At the present moment hardware and software of the complex are being developed to improve its reliability, accuracy of measurements and results of calculation. The paper discusses topical tasks of monitoring and analysis of lightning activity. The instrumentation which was used to record VLF signals is described. Algorithms for whistler detection and for filtration of atmospherics associated with whistlers are suggested as well as the algorithms for search of possible regions of lightning activity affecting whistler occurrence in a defined region. The algorithm of search compares each detected whistler with the data of the World Wide Lightning Location Network. The algorithm for whistler detection in a spectrogram is based on a nonlinear transform of "time-frequency" coordinates to straighten a whistler pattern followed by recognition of this straight line to operate in real time system. The paper aims at demonstrating the capabilities of application of the instrumentation and the software which are applied and are being developed to investigate natural phenomena associated with lightning activity. During the work process, we solve the problems on the development of cluster hardware-software complex of heterogenic data analysis; development of a specialized system of complex event processing for lightning data analysis in real time mode; search for the regions and events affecting whistler occurrence in a defined region and so on.
HIGH-LATITUDE IONOSPHERIC IRREGULARITIES: DIFFERENCES BETWEEN GROUND- AND SPACE-BASED GPS MEASUREMENTS DURING THE 2015
ST. PATRICK'S DAY STORM
Cherniak Iu., Zakharenkova I.
West Department of IZMIRAN (IZMIRAN Kaliningrad branch)
We present an analysis of ionospheric irregularities at high-latitudes during
35
the 2015 St. Patrick’s Day storm. Our study used measurements from ~2700 ground-based GPS stations and GPS receivers onboard five Low Earth Orbit (LEO) satellites—Swarm A, B and C, GRACE and TerraSAR-X—that had close orbit altitudes of ~500 km, and the Swarm in situ plasma densities. An analysis of the Rate of TEC index (ROTI) derived from LEO GPS data, together with Swarm in situ plasma probe data, allowed us to examine topside ionospheric irregularities and to compare them to the main ionospheric storm effects observed in ground-based GPS data. We observed strong ionospheric irregularities in the topside ionosphere during the storm’s main phase that were associated with storm enhanced density (SED) formation at mid-latitudes, and further evolution of the SED plume to the polar tongue of ionization (TOI). Daily ROTI maps derived from ground-based and LEO GPS measurements show the pattern of irregularities oriented in the local noon-midnight direction, which is a signature of SED/TOI development across the polar cap region. Analysis of the Swarm in situ plasma measurements revealed that, during the storm’s main phase, all events with extremely enhanced plasma densities (> 106 el/cm3) in the polar cap were observed in the Southern Hemisphere. When Swarm satellites crossed these enhancements, degradation of GPS performance was observed, with a sudden decrease in the number of GPS satellites tracked. Our findings indicate that polar patches and TOI structures in the topside ionosphere were predominantly observed in the Southern Hemisphere, which had much higher plasma densities than the Northern Hemisphere, where SED/TOI structures have been already reported earlier. LEO GPS data (ROTI and topside TEC) were consistent with these results. This work was partially funded by RFBR according to the research project No. 16-05-01077 a.
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AURORA AS MARKER OF GPS/GLONASS SIGNALS PROPAGATION
Chernouss S.A.1, Shagimuratov I.I.1,2, Filatov M.M.1, Efishov I.I.2, Ievenko I.B.3, Shvec M.V.1,
Tepenitsina N.Yu.2, Kalitenkov N.V.4, Kopytenko Yu.A.5
1 - Polar Geophysical Institute 2 - West Filial of IZMIRAN
3 - IKFIA RAS 4 - Murmansk State Technical University
5 - St.Petersburg Filial of IZMIRAN
The comparative analysis of the ionospheric total electron content (TEC) and an aurora intensity which characterized changing in the polar ionosphere during substorm, is presented.for January 7,2015 and March 17, 2015. TEC data were obtained from the network of GPS-GLONASS stations over auroral and subauroral zones and auroral images in different emissions were obtained from numerical optical observations data. Temporal and spatial distribution of rate of TEC index (ROTI) and optical aurora were also constructed on the base of the famous models. It is shown similarity of the auroral ovals and distribution of TEC irregularities.. Optical measurements in this day were provided by the spectral images in main auroral emissions OI 555.7, OI 630.0, N2
+ 470.9 and H 486.1 nm at subauroral Yakutsk and auroral Poker Flat stations.during the day January 7, 2015. They characterized by high activity as isolated storm in the time span 07-13 UT. During this time both auroral activity and quantity of irregularities sharply increased in the same sector of local time. The storm March 17 continued a whole day and aurora reached latitude of St.Petersburg. Auroral images in this place together with TEC variations also are under discussion. Prediction of ionospheric TEC irregularities appearance was imitates by using the NORUSKA model of aurora prediction for presented data. This model designed by Russian and Norwegian scientist in joint project NORUSKA. Calculated oval position was compared with position of ionospheric irregularities from GPS measurements in numerical stations. We have observed a similarity of these
37
pictures but precision of that was not yet enough for practical tasks. Possibility of optical auroral measurement using for the forecasting of positioning errors is under consideration too. Authors thanks to RFBR grant r-sever-a and and 15-45-05090r_vostok-a for support of this work.
PROPERTIES OF FREQUENCY DISTRIBUTION OF PC5-RANGE PULSATIONS OBSERVED WITH THE EKATERINBURG DECAMETER RADAR IN THE
NIGHTSIDE IONOSPHERE
Chtlpanov M.A., Mager O.V., Mager P.N., Klimushkin D.Yu., Berngardt O.I.
Institute of Solar-Terrestrial Physics
Radar studies often tend to identify the high-m Pc5 waves with the Alfvén modes. Nevertheless, the nature of such waves is not always clear. A study of 16 events of Pc4 and Pc5-range magnetospheric waves is presented in order to determine a portion of pulsations that indeed could be associated with the Alfvén mode. The events were observed with the coherent decameter Ekaterinburg radar (Russia) in the nightside ionosphere in 2014 and 2015. The data sets underwent wavelet analysis. Spacecraft data on magnetic field and particle density from the sectors of radar observation were used to model Alfvén frequency of field lines. It was calculated for the L shells at that the ionosphere flow velocity oscillations occurred for every event individually. The comparison of radar and spacecraft data revealed that only a small part of the harmonics observed with the radar has frequencies that are close to the Alfvén one. The majority of the waves feature considerably lower frequencies. They probably could be attributed to the drift-compressional mode.
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OSCILLATIONS OF 2D INHOMOGENEOUS MHD-WAVEGUIDE IN THE OUTER MAGNETOSPHERE
Chuiko D.A., Mazur V.A.
ISTP SB RAS
The geomagnetic field and plasma inhomogeneities in the outer equatorial part of the magnetosphere are responsible for the existence of the channel with low Alfven speeds, which extends from the nose to the far flanks of the magnetosphere, both in the morning and evening sectors. This channel serves as a waveguide in the fast magnetosonic waves. Travelling along the waveguide (i.e., in the azimuthal direction), an eigenmode undergoes evolution. Parameters of the waveguide vary along the way of the wave propagation and the eigenmode “adapts” to these parameters. Conditions of the Kelvin-Helmholtz instability change due to the variation of the solar wind speed along the magnetopause. Conditions of the penetration of solar wind hydromagnetic waves into the magnetosphere change due to the same variation. The wave penetration process turns to the overreflection regime, which sharply amplifies the pump level of the magnetospheric waveguide. The fast mode propagating along the waveguide is ac-companied by the Alfven resonance deep within the magnetosphere. Oscillation energy dissipation takes place in the vicinity of the Alfven resonance. Along the magnetic field lines, the Alfven resonance is a standing Alfven wave; thus it reaches the ionosphere and the Earth’s surface. At the same time, no fast waveguide modes localized in the low Alfven speed channel can be observed on the Earth. Waveguide oscillations evolution is investigated in this paper both analytically and numerically taking into account all of the aforementioned factors as the oscillations propagate from the nose to the tail of the magnetosphere. Spectral composition and spatial structure of the oscillations are found. The theory allows for a description of Pc3 and Pc5 pulsations – the most important magnetospheric pulsations. As such it follows that Pc3 are localized on the dayside of the magnetosphere, whereas Pc 5 are localized in the dawn-dusk sectors – in full agreement with the observations.
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IDENTIFICATION OF THE SOURCE OF QUASIPERIODIC VLF EMISSIONS USING GROUND-
BASED AND VAN ALLEN PROBES SATELLITE OBSERVATIONS
Demekhov A.G.1,2, Titova E.E.1, Kozelov B.V.1, Pasmanik D.L.2, Manninen J.3, Santolik O.4,
Kletzing C.A.5, Reeves G.6
1 - Polar Geophysical Institute, Apatity, Russia 2 - Institute of Applied Physics, RAS, Nizhny Novgorod, Russia
3 - Sodankyla Geophysical Observatory, Sodankyla, Finland 4 - Institute of Atmospheric Physics, ASCR, Prague,
Czech Republic 5 - Department of Physics and Astronomy, University of Iowa,
Iowa City, Iowa, USA 6 - Los Alamos National Laboratory, Los Alamos, New Mexico,
USA
We discuss quasiperiodic VLF emissions (in the frequency range 2 to 6 kHz) observed by Van Allen Probe A and a ground based site in Kannuslehto (Northern FInland) during a substorm of January 25, 2013. The spacecraft detected them in the night sector at L = 3.0 to 4.2 when it was in the plasmasphere. Their quasi-period decreased from 6 to 3 min during the event. We find one-to-one correspondence between the quasiperiodic elements detected in space and on the ground, which indicates the temporal nature of the observed quasi-period variation. Multiсomponent measurements of the wave electric and magnetic fields by the Van Allen Probe A show that the quasiperiodic emissions were almost circularly right-hand polarized whistler mode waves and had predominantly small (below 30°) wave vector angles with respect to the magnetic field. In the probable source region of these signals (L about 4), we observed synchronous variations of electron distribution function at energies of 10–20 keV and the quasiperiodic elements. In the pause between the quasiperiodic elements pitch angle distribution of these electrons had a
40
maximum near 90°, while they become more isotropic during the quasiperiodic elements. The growth rate of whistler mode waves calculated for the electron distribution functions measured by Van Allen Probe A corresponds well to the spectra of observed emissions. We propose to explain the quasiperiodic emissions by auto-oscillationi regime of the cyclotron instability and simulate such regimes using the flow cyclotron maser model for the parameters close to the measured ones.
POYNTING FLUX DIRECTIONS OF VLF CHORUS EMISSIONS IN THEIR SOURCE REGION AS
INFERRED FROM THEMIS DATA
Demekhov A.G.1,2, Taubenschuss U.3, Santolik O.3
1 - Polar Geophysical Institute, Apatity, Russia 2 - Institute of Applied Physics RAS, Nizhny Novgorod, Russia
3 - Instute of Atmospheric Physics, ASCR, Prague, Czech Republic
We present results of observations of VLF chorus emissions based on several events detected by THEMIS spacecraft within the source region. Using energetic particle distributions measured onboard the spacecraft, we calculate the whistler-mode growth rates and compare them with those for the observed chorus elements. We find that in several cases the measured energetic particle distribution does not explain the measured growth rates, which may indicate that the actual velocity space gradients of the energetic electron distribution are larger than the particle detector can resolve. Using THEMIS multicomponent wave data on parallel propagating chorus elements detected at some distance from the magnetic field minimum, we show that the elements propagating equatorward had systematically higher frequencies and smaller amplitudes compared with simultaneously observed elements propagating away from the equator. The exponential growth of the elements propagating in both directions had close values. We propose an explanation of the observed feature on the basis of the evolution of energetic electron distribution function in the course of VLF wave generation. The motion of electrons from the equator is accompanied
41
by a decrease in their parallel velocity, which causes an additional increase in the wave frequency of chorus elements generated by such electrons and propagating equatorward. The elements propagating in the opposite direction, i.e., from the equator, are formed by electrons whose parallel velocities are larger due to the adiabatic mirror force. Correspondingly, such electrons generate waves with lower frequencies. We present the results of numerical simulations confirming the proposed mechanism.
2-D MODEL OF THE IONOSPHERIC CONDUCTOR
Denisenko V.V.
Institute of Computational Modelling, Russian Academy of Sciences Siberian Branch
For mathematical simulation of large-scale electric fields in the magnetosphere and ionosphere one needs to know parameters of generators and the conductivity distribution. We have created the model of conductivity. The height distribution of the components of the conductivity tensor is derived from the empirical models IRI, MSISE, IGRF. The distributions are modified for approximation of the transition of the conductor in the drift motion under the action of Ampere force. For the daytime ionosphere it is equivalent to the traditional exclusion of conductivity of F-layer, and at night the F-layer remains paramount when Pedersen conductivity is calculated. A significant simplification of the electrical conductivity problem is associated with the presence of the small parameter that is the ratio of Pedersen Pσ and field-aligned σ�
conductivities /Pε σ σ= � . We use the approximation 0ε = instead of 0ε → that corresponds σ = ∞� . Then the magnetic field lines are
equipotential ones, and charge transfer between them is determined only with integral Pedersen PΣ and Hall HΣ conductivities, which are calculated by integration of the local ones along a magnetic field line. For
0ε = the original 3-D steady state electroconductivity problem is reduced to a 2-D one. The problem is additionally simplified with separation of the thin boundary layer that corresponds to the equatorial electrojet. This layer
42
is simulated with the boundary condition with one parameter that equals to Cowling conductivity
2 2( ) /C P H PΣ = Σ + Σ Σ , integrated across the layer. This research is supported by grant 15-05-00879 from the Russian Foundation for Basic Research.
CLIMATIC PERIODICITIES IN THE VARVE THICKNESESS OF THE PRECAMBIAN ELATINA
FORMATION AND SOLAR ACTIVITY CYCLICIITY
Dergachev V.A.1, Dmitriev P.B.1, Tyasto M.I.2
1 - Ioffe Institute, Sankt-Petersburg, Politekhnicheskaya, 26 2 - St-Petersburg Filial of Institute of Terrestrial Magnetism,
Ionosphere and Radiowave Propagation (SPbF IZMIRAN) of RAS, St-Petersburg
Variations in the annual varve thicknesess of the Precambian Elatina Formation (~680 million years ago) are studied. These paleoclimatc data enclosed the time period about 1300 years and have been investigated in order to reveal quasiperiodic variations of climatic processes in the past. By using the method of combined spectral periodograms (CSP) of variations in the varve thicknesess, quasi-harmonic components with the periods similar to modern basic solar activity cyclicity have been revealed. This suggests that the Earth’s climate was influenced by the solar activity at the time of the varve formation.
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NATURE OF THE 2300-YEAR CYCLE OBSERVED IN THE CONCENTRATION OF COSMOGENIC ISOTOPES
Dergachev V.A., Vasiliev S.S.
Ioffe Institute, Sankt-Petersburg, Politekhnicheskaya, 26
The spectral analysis of the data on cosmogenic isotopes 10Be and 14C during the last 10 thousand years points to the existence of 2300-year cyclical changes in concentrations of these isotopes in the Earth's atmosphere. Apparently, these changes in concentrations are not associated with meteorological effects [Damon and Sonett (1991), Beer et al. (1988)]. During solar activity minima (Spoerer, Maunder, and Dalton) an increase of cosmic ray intensity wa observed. The mean time interval between these minima is about 2000 years. This suggests a possible connection between n the solar activity and 2300-year cycle in the concentration of cosmogenic isotopes in the Earth's atmosphere [Damon and Jirikovic (1992), Dergachev (1994)]. However, up to now it was not possible to show convincingly that the change of solar activity is the main reason of 2300-year cycle. Alternatively, variations of the geomagnetic field could result in appearence of this cycle. Precise measurements of the change of magnetic field of the Earth for several thousands years [Korte et al. (2011)] have allowed us to investigate the relationship between the variations in the dipole moment and the production rate of cosmogenic isotopes. We have made the analysis of the Korte et al. (2011) data for the last10 thousands years. Temporal variations of the dipole moment were analysed by making use the method of Empirical mode decomposition (EMD) [Huang et al. (1996)]. It is shown that the empirical modes besides a well-known long-term component (~ 10 thousand years) also contain a ~ 2300-year cycle mode. The same method was applied to study the production rate of cosmogenic isotope 10Be [Vonmoos et al. (2006)]. Comparison of variations in the dipole moment and the 10Be production rate shows that the 2300-year changes are synchronous. The magnitude of the changes corresponds to the model calculation of the production rate of cosmogenic isotopes in the Earth's atmosphere [Masarik and Beer (1999)]. Hence, there are strong reasons to assume that the 2300-year cycle observed in cosmogenic isotopes concentrations has geomagnetic nature.
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AURORAL DISTURBANCES DURING ST. PATRICK'S DAY GEOMAGNETIC STORMS IN 2013 AND 2015
Despirak I.V.1, Kozelov B.V.1, Guineva V.2
1 - Polar Geophysical Institute, Apatity, Russia 2 - Space Research and Technology Institute, BAS, Stara Zagora,
Bulgaria
This study presents an analysis of the ground-based observations of the auroral and geomagnetic disturbances during two geomagnetic storms on March 17, 2013 and March 17-18, 2015. The first event on March 17, 2015 is the principal event covering the interval from 15 to 18 March 2015, in which solar eruptive phenomena (a long-enduring C9-class solar flare and associated CME(s) on 15 March) and a strong geomagnetic storm on 16-18 March (Dst ~ -228 nT) were reported. This magnetic storm was the largest one observed in the current solar cycle. The second event is the period on 17-18 March 2013 which was strong geomagnetic storm (Dst ~ -140 nT) developed. This storm was caused by magnetic cloud in the solar wind. Solar wind and interplanetary magnetic field parameters were taken from OMNI data base. The magnetograms of the IMAGE network and Observations of the Multiscale Aurora Imaging Network (MAIN) in Apatity were used as indicator of auroral activity. The particularities in the behaviours of substorms connected with different storms during these two interesting strongly disturbed periods are discussed.
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HIGH LATITUDE SUBSTORMS DURING THE 23-TH AND 24-TH SOLAR CYCLES
Despirak I.V.1, Lyubchich A.A.1, Kleimenova N.G.2
1 - Polar Geophysical Institute, Apatity, Russia 2 - Institute of Physics of the Earth RAS, Moscow, Russia
We presented the comparative analysis of the magnetic substorm behavior during the 23-th and 24-th solar cycles on the base of the IMAGE magnetometer chain observations and the OMNI solar wind and Interplanetary Magnetic Field (IMF) data. The substorms have been studied in: (a) close to the 23-th solar cycle maximum (1999- 2000, Wp> 100); (b) close to the last maximum (2012-2013, Wp~60), (c) during the 23-th and 24-th solar cycle minima (1995-1996, Wp=3-17 and 2008-2009, Wp=3). We have analyzed the occurrence of the magnetic substorms at high geomagnetic latitudes; as in previous study, we divided the considered substorms into 2 types according to auroral oval dynamics. The first type – the substorms which propagate from auroral geomagnetic latitudes (<70º) to the polar ones (>70º), termed “expanded” substorms according to an expanded oval. The second type – the substorms which are observed only at latitudes above ~70º in the absence of simultaneous geomagnetic disturbances below 70° (called “polar” substorms, according to a contracted oval). We have analyzed the space weather conditions before the onset of these two substorm types. Namely, we have considered the influence of the solar wind and IMF parameters, of the polar cap PC-index, high-speed solar wind streams and magnetic storm development, substorm seasonal variations and etc. It was found that although “polar” and “expanded” substorms observed at almost identical high geomagnetic latitudes, they appear under different space weather conditions and, presumably, are related to different sources.
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STORM-TIME ELECTRON TEMPERATURE AND DENSITY AT R=6-11 RE (EMPIRICAL MODELS)
Dubyagin S.1, Ganushkina N.1,2, Sillanpää I.1, Runov A.3
1 - Finnish Meteorological Institute 2 - University of Michigan
3 - University of California, Los-Angeles, USA
We will present empirical models of the electron density and temperature distributions in the equatorial plane at r=6-11 Re on the night side. The models are constructed using the high quality THEMIS plasma measurements covering the energy range 30 eV-300 keV. The dataset comprises more than 400 hours of observations in the plasma sheet during geomagnetic storms in 2010-2013. The models include spatial dependence as well as dependence on the solar wind driving parameters. The emphasis is made on the analysis of the temporal lag of the electron plasma sheet response to the change of solar wind parameters. The model can be used as a boundary condition for the inner magnetosphere particle (electron) simulations.
PREDICTION OF MAXIMUM DAILY RELATIVISTIC ELECTRON FLUX AT GEOSTATIONARY ORBIT BY
ADAPTIVE MODELS
Efitorov A., Myagkova I., Dolenko S.
D.V.Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University, Moscow, Russia
This study presents 1-3 days prediction of the time series of daily max hourly values of relativistic electrons flux (E>2 MeV) in the outer radiation belt of the Earth. Our database of predictors covers the years 1996–2003.
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We obtained hourly averaged values of Dst, AE, Kp geomagnetic indexes, Bz component of the interplanetary magnetic field (in GSM coordinate system), solar wind flow velocity and proton density (N/cm³) from the Omniweb data base [1] and relativistic electron flux (> 2 MeV, > 0.6 MeV) from the GOES data base, GOES-8 spacecraft [2]. The phase-space for each physical component was reconstructed by time-delay vectors with their own different embedding dimensions, and all of these vectors were concatenated. Next, various adaptive models were trained on this multivariate dataset. A lot of models, such as simple autoregressive models, group method of data handling, artificial neural networks and others, were compared. The obtained results are analyzed and compared to the results of similar predictions by other authors [3]. 1. Omniweb database, hourly average valueshttp://cdaweb.gsfc.nasa.gov/misc/NotesO.html#OMNI2_H0_MRG1HR 2. GOES-8 spacecraft datahttp://cdaweb.gsfc.nasa.gov/misc/NotesG.html#G0_K0_EP8 3. Simms, L. E., M. J. Engebretson, V. Pilipenko, G. D. Reeves, and M. Clilverd (2016), Empirical predictive models of daily relativistic electron flux at geostationary orbit: Multiple regression analysis, J. Geophys. Res. Space Physics, 121, 3181–3197, doi:10.1002/2016JA022414. *This study was supported by RFBR grant no. 14-01-00293-a
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ACCELERATION OF PLASMA FLOW IN THE MAGNETOSHEATH DUE TO MAGNETIC FIELD
DRAPING
Erkaev N.V.1, Farrugia C.J.2, Mezentsev A.V.1, Ivanov V.A.1
1 - Institute of Computational Modelling SB RAS, Krasnoyarsk, Russia
2 - Space Science Center, University of New Hampshire, USA
Solar wind flow around magnetosphere results in draping of the interplanetary magnetic field lines around the magnetosphere. The curved magnetic field produces magnetic tension force accelerating plasma flow in direction perpendicular to the magnetic field. The bulk speed of the accelerated plasma can exceed the solar wind speed. Velocity maximum is larger when the Alfven Mach number is lower. This effect is the most pronounced in the magnetic barrier, where the magnetic forces are stronger. Our study is concerning behavior and location of the accelerated flow in dependence on direction of the interplanetary magnetic field (IMF) and shape of the magnetospheric boundary, which is approximated by analytical formula.
HALL MHD SIMULATION OF THE MAGNETIC RECONNECTION AT THE MAGNETOPAUSE
Erkaev N.V., Mezentsev A.V., Ivanov V.A., Dement'eva E.V.
Institute of Computational Modelling SB RAS
We apply a Hall MHD model with finite conductivity for simulation of magnetic reconnection in a thin layer near the magnetopause. The outer
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boundary conditions are taken from the ideal MHD flow around the magnetosphere. The inner boundary conditions for reconnection layer are chosen to be relevant to the inner magnetospheric region adjacent to the magnetopause. Magnetic reconnection rate is related to the finite conductivity of plasma. Numerical simulations of magnetic reconnection are performed for different solar wind Alfven-Mach numbers and magnetic Reynolds numbers. Tangential electric field and normal magnetic field components at the magnetopause are determined as functions of the magnetic Reynolds number. Acceleration of plasma in the reconnection region is calculated for different clock angles of the interplanetary magnetic field and solar wind Alfven-Mach numbers.
ANALYTICAL MODEL OF DOUBLE GRADIENT MHD WAVES IN CASE OF NON-SYMMETRIC
MAGNETOTAIL CURRENT SHEET
Erkaev N.V.1, Semenov V.S.2, Kubyshkina D.I.2, Ryzhkov I.I.1, Kozlova S.V.1
1 - Institute of Computational Modelling SB RAS, Krasnoyarsk, Russia
2 - Saint Petersburg State University, Saint Petersburg, Russia
We study eigenmodes of the MHD waves propagating along the magnetotail current sheet in direction perpendicular to the magnetic field. Wave frequency is proportional to the square root of the product of the magnetic field gradients corresponding to the neutral line. These gradients are the normal and tangential gradients of the tangential and normal magnetic field components, respectively. As a background we consider analytical solution for 2-D steady state magnetic field configuration characterized by a non-symmetric magnetic field profiles across the current sheet. Deviation of the non-symmetric magnetic field profile from the symmetric one is dependent on the special asymmetry parameter. Varying this parameter, we analyzed an influence of the current sheet asymmetry on the wave oscillations. In symmetric case, the wave oscillations can be kink-type or sausage type modes, which are independent from each other. But in
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case of asymmetry a pure kink-type or sausage type wave does not exist. In such case, each eigenmode becomes a mixture of the sausage and kink types. Wave frequencies and group speeds as functions of wave number are determined for symmetric and asymmetric current sheets.
AN INFLUENCE OF THE HALL MHD EFFECT ON THE MAGNETIC BARRIER FORMATION
Erkaev N.V., Mezentsev A.V., Ivanov V.A., Dement'eva E.V.
Institute of Computational Modelling SB RAS, Krasnoyarsk, Russia
Solar wind flow around magnetosphere leads to formation of the enhanced magnetic field layer near the magnetospheric boundary, which is called magnetic barrier. The magnetic barrier thickness is about the subsolar distance divided to the Alfven Mach number squared. In this layer the magnetic pressure is dominating over the plasma pressure. In the framework of the ideal MHD flow model, the magnetic pressure maximum at the subsolar point is about the solar wind dynamic pressure. Any violation of the magnetic field frozen-in condition leads to diminish of the magnetic field pile-up near the magnetopause. In particular, in the Hall MHD model, the magnetic field lines are not frozen-in to protons and thus the magnetic field pile-up at the magnetopause is expected to be less than that in the ideal MHD model. The role of Hall terms is characterized by the dimensionless parameter determined as a ratio of the proton inertia length to the magnetic barrier thickness. We study an influence of the Hall parameter on the magnetic barrier structure and magnetic field maximum.
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THE SPATIAL DISTRIBUTION OF THE ULF MAGNETIC FIELD OF MULTIBAND PC1
FREQUENCIES
Ermakova E.N.1, Shennikov A.V.1, Kotik D.S.1, Pershin A.V.1, Yahnin A.G.2, Yahnina T.A.2
1 - Radiophysical Research Institute, Nizhny Novgorod State University, Nizhny Novgorod, Russia
2 - Polar Geophysical Institute, Apatity, Russia
The studies were carried out on the basis of spaced registration of horizontal magnetic component on the mid-latitude RRI observatories New Life (56N, 45.74E) and Old Pustyn (55.66 N, 43.63E, located 120 km to the east of the first reception point). We analyzed the ULF data during periods of strong magnetic storms in 2011 and 2015. The amplitude spectra and the spectra of the polarization parameter were investigated. Also the data of the localized precipitation of energetic (E>30 keV) protons (LPEP) by low-orbiting NOAA satellite and data of an ionosonde, located in 25 km from the station New Life were analyzed. It was found that the difference in the amplitudes of these stations should not exceed 5-20% during the storm 06.03.2011 at night time. Estimated attenuation of waves at Pc1 frequencies in the MHD waveguide is varied in the range of 13-20 dB/Mm considering that the stations have been separated in the West direction by 120 km and taking into account the satellite data. However, in some periods of magnetic storms 06.03.2011 and 13.11. 2015 the difference in Pc-1 amplitude at these stations was 50-80%. At the same time the different character of the polarization of magnetosphere radiation also was detected. Such a difference of the amplitude can not be explained on the basis of the attenuation in the MHD waveguide taking into account that LPEP on the satellites NOAA during this period 06.03.2011 were found near the magnetic meridian of these stations. The occurrence of sporadic Es layer was registered according ionosonde data during the detection of amplitude and polarization difference at the Pc1 frequencies at separated stations 13.11.2015. The appearance of sporadic layers can lead to the horizontal inhomogeneity of
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ionospheric MHD waveguide with a characteristic size of the order of the distance between the receiving points. Also the assumption can be made that the registration of a significant difference in the spectra of Pc1 at stations separated by 120km may indicate a possible declination of magnetospheric wave propagation from the direction of the geomagnetic field line and entering of the radiation at lower geomagnetic latitudes near the ground reception points.
ANALYSIS OF METHODS FOR ESTIMATING EQUIVALENT IONOSPHERIC CURRENT FROM
MERIDIAN MAGNETOMETER CHAIN DATA
Evdokimova M.A., Petrukovich A.A.
Space Research Institute of the Russian Academy of Sciences
This work presents the investigation of methods for estimating equivalent ionospheric current using magnetic field observations along a meridian chain of ground-based magnetometers. The analysis is carried out for the magnetospheric substorm on November 24, 1996. This problem is interesting because the data of the magnetic field are given in the finite, rather little number of points. In the first method (A.L. Kotikov, Yu.O. Latov and O.A. Troshichev, 1987) the ionospheric electrojet is modeled by a sequence of current lines. In the second method (V.A. Popov, V.O. Papitashvili, J. F. Waterman, 2001) the electrojet is modeled by the sequence of narrow current strips. Using the regularization technique, we find the dependence of the current from the latitude in the fixed moments of time with the different number of lines (strips) and different parameters of regularization. Practical applicability of modified models was investigated and analysis of the errors was carried out.
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WAYS TO PROVIDE THE FLIGHT SAFETY OF ORBITAL SPACECRAFT’S WITH IT’S OUTER
ATMOSPHERE MONITORING
Gaponov V.A., Kavtrev S.S.
Russian State Scientific Center for Robotics and Technical Cybernetics (RTC), St. Petersburg, Russia
Research the spacecraft’s own outer atmosphere is the way to provide the flight safety. In orbital flight own outer atmosphere is one of the main factors affecting the structural elements of the spacecraft and posted on the external surface of the equipment, which largely determine the safety, security and efficiency of the spacecraft as a whole. Substances from the own outer atmosphere’s cloud, deposited on the surface of the spacecraft. Most sensitive to contamination are the optical surfaces, temperature-control coatings, electronics and solar panels. Own outer atmosphere’s products for a long time accompany the spacecraft in flight, forming a cloud of gas and particles that scatter light; may interfere with the spacecraft orientation, observations pale light sources, as well as the observations of the scattered ultraviolet radiation from the sun. Improvement of methods and means of controlling the parameters of the diagnosis of spacecraft’s and orbital station’s own outer atmosphere will allow: - Significantly increase the reliability of containment, both in terms of the safety of the crew, as well as in terms of increasing the life of the space object; - Develop the principles of creation of means of control of leakage, with the definition of specific emergency sealed modules as manned and unmanned spacecraft, including the identification of the location of the leak; - To create in the near future devices secure and reliable determination of leakage in the shell defects of space objects to further ensure the safety of the crew living in ecologically closed systems, and measures to increase the duration of their lifetime; - Develop the measure to ensure the safety of the crews that are in a vacuum exposure, depleted or polluted and harmful gaseous medium
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discharge plasma environment surrounding objects (orbital and interplanetary space station, manned transport spacecraft and research).
INTERPRETATION OF PLASMA SHEET FLAPPING OSCILLATIONS CONJUGATE TO THE EAST-WEST
AURORAL ARCS IN THE IONOSPHERE
Golovchanskaya I.V., Mingalev I.V., Kornilova T.A.
Polar Geophysical Institute
We study the events of plasma sheet flapping oscillations magnetically conjugate to the east-west aligned (E-W) auroral arcs at substorm growth phase, assuming that these two phenomena are interrelated. From in situ spacecraft observations it appears that flapping oscillations in such events can hardly be interpreted within ballooning/flapping type models, generating strongly elongated tail-aligned structures of constant (or weakly varying along the tail) amplitude. Nor the E-W arc topology supports their relevance in our case. This motivates us to search for alternative generation scenarios. As the simultaneously occurring E-W auroral arcs are well explained by the theory of field line resonances (FLRs) [Southwood, 1974; Samson et al., 2003], we test the possibility that this same theory is able to explain the associated flapping oscillations. For a particular event, the eigenmode problem is solved for a perturbation of the form suggested by the FLR theory. The eigenfrequencies and eigenfunctions calculated for the first and second FLR harmonics are compared with observations and an overall agreement is demonstrated. The observed and modeled FLRs have both toroidal and poloidal components, the latter manifesting as flapping in a stretched magnetic geometry. It is concluded that different generation mechanisms are conceivable for flapping perturbations.
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THE SUBSTORM CYCLE AS REPRODUCED BY COMMUNITY-AVAILABLE GLOBAL MHD MODELS
Gordeev E.1, Sergeev V.1, Tsyganenko N.1, Kuznetsova M.2, Raeder J.3, Toth G.4, Merkin V.5
1 - St. Petersburg State University 2 - GSFC NASA
3 - University of New Hampshire 4 - University of Michigan
5 - John Hopkins University
In this study we investigate how three community-available GMHD models supported by the Community Coordinated Modeling Center (CCMC NASA) reproduce the global magnetospheric dynamics, including the loading-unloading cycle. We found that in terms of global magnetic flux transport, i.e. by comparing the tail magnetic flux variations (dFT/dt), the dayside merging-induced tailward convection (CPCP), and the return convection (CTP), CCMC models display systematically different response to idealized 2-hour north then 2-hour south IMF Bz variation. The LFM model shows a depressed return convection and high loading rate during the growth phase as well as enhanced return convection and high unloading rate during the expansion phase, with the amount of loaded/unloaded magnetotail flux and the growth phase duration being the closest to their observed empirical values during isolated substorms. Two other models exhibit drastically different behavior. In the BATS-R-US model the plasma sheet convection shows a smooth transition to the steady convection regime after the IMF southward turning. In the Open GGCM a weak plasma sheet convection (CTP smaller than CPCP) has comparable intensities during both the growth phase and the following slow unloading phase.
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SECONDARY MHD WAVES IN THE MAGNETOSHEATH BEFORE THE
MAGNETOSPHERE OF THE EARTH
Grib S.A.1, Leora S.N.2
1 - Central (Pulkovo) Astronomical Observatory, Saint-Petersburg, 196140, Russia
2 - Saint-Petersburg State University, Faculty of Mathematics and Mechanics, Saint-Petersburg, Russia
We examine the frequently observed macroscopic solar wind discontinuity structures from the perspective of magnetohydrodynamics (MHD) using the solution of the generalized problem of Riemann-Kotchine. Specific attention is given to the appearance of MHD discontinuities inside the magnetosheath after the impact of the solar wind strong discontinuity on the terrestrial bow shock wave. The possibility is explored for generation of a refracted discontinuity such as fast shock wave, tangential or contact discontinuity and a MHD rarefaction wave. As we demonstrate a reverse MHD shock wave with direction toward the Sun inside the magnetosheath emerges as a result of breaking of a secondary MHD wave, which is reflected from the magnetopause. In certain instances the former type of wave may emerge out of a contraction wave that is reflected from the plasmasphere inside the magnetosphere [Samsonov et al., 2007]. Our theoretical calculations find support in the bow shock wave motion data, provided by the Double Star and Cluster spacecrafts. We also discuss the collision of the solar wind rotational discontinuity with the front of the bow shock wave [Pushkar’, 2010], focusing specifically on the generation of the plasma plateau inside the magnetosheath. It’s possible to indicate that secondary MHD waves and the structure called plateau appeared in the result of the effect of solar wind waves are important in the generation of plasma non homogeneous regions in the magnetosheath. The contraction waves inside the magnetosheath may become a source for the reverse MHD shock waves due to nonlinear effects. The observed depressions of the magnetic field with the increase of the plasma density demonstrate the existence of the plateau. The work was completed with partial support from
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the P-7 Program of the Presidium of the Russian Academy of Sciences and the RFBR grant № 14-01-0335.
HIGH-LATITUDE GEOMAGNETIC RESPONSE TO THE SPACE WEATHER DURING THE INTENSE
MAGNETIC STORM ON JUNE 22-23, 2015
Gromova L.I.1, Kleimenova N.G.2,3, Gromov S.V.1, Dremukhina L.A.1, Levitin A.E.1, Zelinsky N.R.2,
Malysheva L.M.2
1 - IZMIRAN 2 - IFZ RAN 3 - IKI RAN
The two steps magnetic storm on 22-23 June 2015 (Dst min= -204 nT) was one of the strongest storms in the 24-th solar activity cycle. The distinctive feature of this storm was the appearance of the several hours interval of high positive IMF Bz values (~ +20 nT) in the storm main phase and the long interval of high negative IMF Bz values (~ -18 nT) in the storm recovery phase. The storm started with SC under very strong solar wind dynamic pressure and negative IMF Bz which ~30 min later reached ~-40 nT and then very quickly turned to ~+20 nT for about 6 hours. That stopped the Dst decreasing at ~120 nT and can represent the first step of this storm. During this storm (23 June) there were two long lasting intervals of the negative IMF Bz values looking like “trough”: one (~02-06 UT) in the main storm phase formed the second step of the storm and another one (~08-12 UT) in the storm recovery phase. The peculiarities of night-side substorms associated with different intervals of negative IMF Bz values are discussed. However, during the positive IMF Bz intervals, the strong magnetic bay-looking disturbances (up to 2000 nT) were observed in the dayside of polar latitudes, that is not indicated in any geophysical index. The temporal dynamics of the polar ionosphere convection was studied basing on SuperDARN data and demonstrated a rather good agreement with high-latitude geomagnetic disturbances. The analysis of geomagnetic pulsations at Scandinavian IMAGE magnetometer chain showed that
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occurrence of the positive IMF Bz suppressed the generation of Pi1 pulsations (T~0.2-4.0 s). According to GOES-13 data, the energetic electron precipitation at geostationary orbit also stopped in this time. The new method of mathematical analysis (generalized variance of the covariance matrix) applied to the geomagnetic Pi3 pulsations (2-7 mHz) analysis showed that under IMF Bz>0 the strong burst of Pi3 pulsations shifted with time from the auroral to the polar latitudes. The relationship between IMF Bz and IMF By fluctuations and ground-based Pi3 pulsations did not found. The obtained results demonstrate that during this magnetic storm, the peculiarieties of high-latitude geomagnetic disturbances are strongly controlled by space weather variations.
MANIFESTATIONS OF THE INTENSE CONVECTION AND SUBSTORM IN THE EVENING MLT SECTOR
FROM THE OBSERVATIONS BY THE ALL-SKY IMAGER
Ievenko I.B., Parnikov S.G., Alexeyev V.N.
Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia
It is known that the enhancement of magnetospheric convection owing to the turn of IMF Bz to the south is manifested more globally than the substorm expansion phase. In this work the observation of the aurora dynamics in the evening MLT sector at the Yakutsk meridian (130ºE; 200ºE, geom.) during a sharp strengthening of magnetospheric convection and two intensive substorms in the midnight sector of MLT in the event on January 7, 2015 using the all-sky imager (ASI) is analyzed. ASI registers the westward motion of the active aurora band with a wavy boundary in the 557.7, 630.0 and 486.1 (Hβ) nm emissions from ~ 09 UT (1710 MLT) after the start of the first substorm at ~ 0850 UT in the MLT midnight sector. The motion occurs with the angular speed of 1-1.2 degrees/min in the station zenith along the geomagnetic latitude of ~58°N. At the same time the undulation of aurora strip along the meridian with the period of 8-9 minutes are observed.
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After the onset of expansion phase of second substorm at ~ 1047 UT at the Yakutsk meridian (~ 1900 MLT) the intensification of aurora in the range of geomagnetic latitudes of 56-61°N is observed. ASI registers the intense SAR arc at the geomagnetic latitudes of 49-52°N from 1112 UT. The measurements aboard the Van Allen Probes A satellite show the sharp increase of fluxes of the energetic electrons and Н+ , О+ ions at 1105-1108 UT at L ~ 2.7 and meridian of ~ 2105 MLT (injection boundary). It is assumed that the westward motion of active aurora band maps the electric drift of energetic plasma at the magnetic equator. The measurements of the particle flux aboard Van Allen Probes A and the ASI’s observation of the SAR arc testify to the penetration of energetic plasma up to L ~ 2.5-2.7 in the evening sector of MLT in this event. The research is supported by RFBR grants No 15-05-02372 a and No 15-45-05090 r_vostok_a.
SAR ARC OBSERVATIONS IN THE EVENTS OF ENERGETIC PLASMA OVERLAPPING WITH A
PLASMAPAUSE BY THE VAN ALLEN PROBE DATA DURING THE STORM AND SUBSTORM
Ievenko I.B.
Yu. G. Shafer Institute of Cosmophysical Research and Aeronomy, Yakutsk, Russia
The stable auroral red (SAR) arcs are the consequence of interaction of the outer plasmasphere (plasmapause) with energetic ions of the ring current. In this work two events of SAR arc observations using the all-sky imager (ASI) at the Yakutsk meridian (130ºE; 200ºE, geom.) simultaneously with a registration of plasmapause and energetic ion fluxes aboard the Van Allen Probe satellites are considered. The first comparison of ground and satellite observations has been carried out during the main phase of large magnetic storm on March 17, 2015 (St. Patrick's Day geomagnetic storm). ASI registers the intense SAR arc at 53-59ºN geomagnetic latitudes in the MLT evening sector from the observation start at ~1116 UT (1926 MLT) during the low magnetic activity
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at IMF Bz > 0. The Van Allen Probe B satellite determines the plasmapause location in the L ~ 3-4 interval and registers the inner boundary of the H+ and O+ energetic ion fluxes at L ~ 2.8-3.3 near the meridian of optical observations. We show that SAR arc in this event maps the overlapping region of plasmasphere dusk-bulge by the energetic ion flux of the ring current after the onset of magnetic storm. In the second event on December 28, 2014 ASI observes the aurora dynamics and formation of SAR arc in early morning sector of MLT after the onset of isolated substorm expansion at ~ 1920 UT with the center of activization at the 0212 MLT meridian. SAR arc arises at 59-57ºN magnetic latitudes during the equatorward and eastward extension of aurora at 1930-2000 UT. The Van Allen Probe B satellite at 1900-1940 UT determines the plasmapause location in the L ~ 4.5-3 interval and registers the plasma sheet inner boundary at L ~ 4 near the optical observation meridian. It is assumed that in this case the dynamics of aurora and SAR arc maps the penetration of hot plasma into the outer plasmasphere as the result of electric drift from the substorm injection region. The research is supported by RFBR grants No 15-05-02372 a and No 15-45-05090 r_vostok_a.
INVESTIGATION OF THE PС5 EVENT IN THE AFTERNOON SECTOR
Ismagilov V.S., Kopytenko Yu.A.
SPBF IZMIRAN, St.-Petersburg, Russia
Several splashes of the geomagnetic pulsations Pc5 were observed in the afternoon sector 27.08.2014. The pulsations had period ~ 360 s and amplitudes up to 100 nT. Using data of 2D IMAGE net and Russian magnetic stations it was shown that the investigated pulsations have some properties do not peculiar to the classic resonance Pc5 pulsations, namely: - the pulsations aroused after 5 days of very quiet magnetic conditions
(Kp index do not exceed +1); - the pulsations aroused in the end of the preliminary phase of substorm; - they faded strongly in latitude and longitude directions; - the pulsations had an elliptic polarization and a phase shift between the
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Pc5 horizontal magnetic components equal to a quarter of the pulsation period;
- several local Pc5 sources were simultaneously observed; - pulsation sources moved in the west direction to the noon meridian
(opposite the Earth rotation) along ~65o CGM latitude. We suppose that sources of the afternoon Pc5 are a sequence of the field-aligned currents pairs (flow in and flow out the ionosphere) moving across the geomagnetic meridians over magnetic stations. The field-aligned currents create the Hall current vortexes in the ionosphere. Observed at the Earth Pc5 pulsations are an effect of magnetic fields of these moving ionosphere currents. Probably the field-aligned currents originate due to some kind of instability at plasmapause in the evening sector (18-20 LT).
SPACE ENVIRONMENT MODELS AND OPERATIONAL SERVICES IN SPACE WEATHER
Kalegaev V.V.
Skobeltsyn Institute of Nuclear Physics, Moscow State University, Moscow, Russia
Modeling is one of the most effective ways in scientific investigations. It is very useful for magnetospheric study due to the lack of the simultaneous measurements in the different regions of the near Earth’s space. Models allow to generalize the data from single observations and give the global view on the magnetosphere or some its large-scale domains. Moreover, space environment models are also important for space weather systems. Together with data coming from satellites and on-ground stations they give possibility for reliable analysis and forecast of physical conditions in space. In science and in space weather we use the models of the same physical phenomena. However there are not the same models. Differences between scientific and operational models are connected with the customer requests that use these instruments. Researchers are the customers of scientific models while the engineers use the space weather services. We should specify the user demands before we will implement the scientific models in space weather system. So, so-called, research-to-operations (R2O) procedure is very important step in space weather operational service
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development. Moreover, a lot of the models are usually working in the framework of space weather systems. In particular, the state of the Earth magnetosphere can not be considered without taking into account the physical conditions in the interplanetary medium and solar activity. Therefore, realistic model of any processes inside the magnetosphere should take into account the physical condition outside the magnetosphere obtained from empirical data or calculated by the special models. In result we need the set of the interconnected models from Sun to the Earth, describing all the critical domains in space and physical processes influencing theses domains. Models interoperability is very important topic as well. In this talk we will discuss the ways of scientific models implementations in the space weather systems.
OPERATIONAL CONTROL OF GEOSPACE RADIATION CONDITIONS IN SPACE MONITORING DATA CENTER OF MOSCOW STATE UNIVERSITY
Kalegaev V.V., Myagkova I., Bobrovnikov S., Barinova V., Eremeev V., Mukhametdinova L., Nguyen M.D.,
Shugau Yu.
SINP MSU
Space Monitoring Data Center (SMDC) of Skobeltsyn Institute of Nuclear physics of Moscow State University (SINP MSU) provides data support for Russian satellites with SINP MSU particle detectors on-board. The measurement data are used for operational analysis of radiation conditions in space and at the given satellite orbits. Satellites are always under the influence of high-energy particle fluxes during their orbital flight. The three main sources of particle fluxes: the Earth’s radiation belts, the galactic cosmic rays, and the solar energetic particles (SEP), are taken into account by SMDC operational services to estimate the radiation conditions caused by high-energy particles at LEO orbits. SMDC Web-sites (http://smdc.sinp.msu.ru/ and http://swx.sinp.msu.ru/) give access to current data on the level of solar activity, geomagnetic and radiation state of Earth’s magnetosphere and heliosphere in the near-real time. For data analysis the
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models of space environment factors working online have been implemented. Interactive services allow one to retrieve and analyze data at a given time moment. A lot of forecasting applications including solar wind parameters, geomagnetic and radiation condition forecasts have been developed.
IMPACT OF SOLAR PROTON EVENTS ON THE CHEMICAL COMPOSITIONS OF THE POLAR
ATMOSPHERE
Karagodin A.V., Mironova I.A.
Saint Petersburg State University
[email protected], [email protected]
This paper presents investigation of chemical composition of odd hydrogen HOx responses to the changes of atmospheric ionization leaded by solar protons and galactic cosmic rays. During January 2005 several solar energetic particle precipitation events increased polar atmospheric ionization by orders of magnitude as well as decreased the polar ionization by Forbush decreases of galactic cosmic rays flux. Results of this study are presented as spatial and temporal distribution of the hydroxyl radical before and after the solar proton events in January 2005. In this paper we confirmed that increasing ionization of atmosphere leads to significant variations of OH in the mesosphere and upper stratosphere. Here for the first time we demonstrate that the reduction in ionization caused by Forbush decreases of galactic cosmic rays results in significant reduction of hydroxyl radical concentration in the middle and lower stratosphere.
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MAGNETOTAIL FAST FLOWS NEAR LUNAR ORBIT
Kiehas S.1, Runov A.2, Angelopoulos V.2
1 - IWF/ÖAW Graz 2 - UCLA, Los Angeles
We use five years (2011-2015) of ARTEMIS data to statistically investigate earthward and tailward flows at around 60 RE downtail. We find that a significant portion (~50%) of fast flows is directed earthward. This contribution reduces with increasing flow speed. As expected, earthward (tailward) flows are predominantly accompanied with positive (negative) Bz. A dawn-dusk asymmetry in the flow occurrence is seen for both earthward and tailward flows with about 50%-60% (60%-70%) of the earthward (tailward) flows occurring in the dusk sector. This asymmetry is more dominant for tailward than for earthward flows and increases slightly with higher flow speeds. Considering only the flow component perpendicular to the magnetic field, the portion of earthward flows reduces to about 30%-40%, depending on the flow speed. The dawn-dusk asymmetry is also seen in this perpendicular flows.
STRUCTURE OF THE HELIOSPHERIC PLASMA SHEET
Kislov R.A.1, Khabarova O.V.2, Malova H.V.3,1
1 - Space Research Institute of the Russian Academy of Sciences 2 - Heliophysical Laboratory, Pushkov Institute of Terrestrial
Magnetism, Ionosphere and Radiowave Propagation RAS (IZMIRAN)
3 - Moscow State University, Institute of Nuclear Physics
We develop a single-fluid 2-D analytical stationary model of axially-symmetric thin heliospheric current sheet embedded into the HPS and
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compare the obtained results with observations. We suggest the HCS-HPS system to be a relatively thin plasma disk that is separated from the Parker solar wind by separatrices at both edges of the HPS. We have found that separatrices represent current sheets as well, which is in agreement with Ulysses observations in the apogee, when it crossed the HCS perpendicular to its plane. Our model employs the differential rotation between the solar photosphere and the corona, which leads to unipolar induction in the corona. Three components of the interplanetary magnetic field (IMF), the solar wind speed, and the thermal pressure are taken into account. The model allows finding spatial distributions of the magnetic field, the speed within the HPS, and electric currents within the HCS. We found that the HPS thickness L decreases with distance r, becoming a constant far from the Sun. L ~2.5 solar radii at 1 AU. The important result is that the IMF spiral may be non-Parker inside the HPS, and even may experience a sharp change of direction under some boundary conditions (Kislov et al., 2015). Additionally, we explore three cases: (i) a purely dipole solar magnetic field of the Sun, (ii) a purely quadrupole magnetic field, and (iii) a mixed case. We show that both the quadrupole and the mixed cases produce additional stable current sheet in the solar wind at higher heliolatitudes, and the last case easily explains the South-North IMF asymmetry. Kislov R. A., O. V. Khabarova, H. V. Malova (2015), A new stationary analytical model of the heliospheric current sheet and the plasma sheet, J. Geophys. Res. Space Physics, 120, doi:10.1002/2015JA021294
CHANGE OF POLARIZATION OF THE LONG-PERIOD ALFVEN WAVES IN DIPOLE-LIKE
MAGNETOSPHERE: THEORY AND OBSERVATIONS
Klimushkin D.Yu., Leonovich A.S., Mager P.N.
Institute of Solar-Terrestrial Physics SB RAS, Irkutsk
Theoretical studies showed that the poloidal Alfven waves generated by a monochromatic source in a dipole-like magnetosphere cannot keep their polarization. Instead, they change their polarization from poloidal into toroidal along with propagation across the magnetic shells. The velocity of
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this propagation is much smaller than the Alfven speed. This transverse propagation and the polarization change are caused by the field line curvature. These theoretical expectations have been confirmed by experiments: the change of the polarization from the poloidal to the toroidal was observed by the RBSP-A satellite. It is shown that the transverse structure of the observed wave well fits the theoretical picture. The RBSP-A satellite was shown to cross two localization regions of the Alfven wave, located near the plasmapause transition layer.
DO THE FACTORS OF SPACE WEATHER ON FAILED MISSILE LAUNCHES?
Klyushnikov V.Yu1, Kozlov S.I.2, Nagorskiy P.M.3, Tasenko S.V.4
1 - TSNIIMASH 2 - Institute of Geosphere Dynamics RAS
3 - Institute of climatic and ecological systems SB RAS 4 - Applied Geophysics Institute of Roshydromet
The analysis of the frequency of accidental launches rocket and space technology, depending on the level and phase of the solar cycle and the season. Attention was drawn in [1] on the possible impact of space weather phenomena (solar and magnetic activity, season, time of day, latitude geomagnetic Cosmodrome) on unsuccessful (emergency) missile launch vehicles for the first time. The purpose of this report is the analysis of the frequency of emergency starts, depending on the level and phase of the solar activity cycle. Official information from websites and information publications Roscosmos and Roshydromet was used as the source data. It was shown [2]: between solar activity and the number of failed start-ups at the launch site, located at different latitudes, there is not an explicit dependence. Not revealed the existence of the emergency communication starts with the season of the year for the USSR (Russia) and the United States.
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1. Kozlov S.I. Klyushnikov V.U., Alpatov V.V., Khrustalev A.B. Preliminary results of the statistical analysis of the data bank of the launch vehicles // Conf. The physics of solar-terrestrial relations. Irkutsk. ISTP RAS, 2001. P.133.
2. The impact of the rocket-kosmicheskoy technology on the environment / Edited V.V. Adushkin, S.I. Kozlov, M.V. Silnikov. M.: GEOS. 2016. 835 p.
E-REGION OF THE IONOSPHERE DURING 2015 ST. PATRICK'S DAY GEOMAGNETIC STORM
Korenkov Yu.N.1, Bessarab F.S.1,2, Klimenko V.V.1, Klimenko M.V.1,2
1 - Kaliningrad Department of IZMIRAN RAS, Kaliningrad, Russia
2 - Immanuel Kant Baltic Federal University, Kaliningrad, Russia
In this paper, we present response of the E- region to the geomagnetic storm of 17 March 2015. The studies have been performed using the Global Self-consistent Model of the Thermosphere, Ionosphere, and Protonosphere (GSM TIP) developed in West Department of IZMIRAN. The input parameters of the model are: solar EUV and UV spectra, precipitating electron fluxes, a cross-polar cap potential and Region 2 field-aligned currents. To modeling of storm-time ionospheric parameters, we used the dependence of the cross-polar cap potential and Region 2 field-aligned currents on the AE index. The model includes interrelation between the cross-polar cap potential and the Region 2 field-aligned currents. The simulations also adopted an empirical model for electron precipitation. In the model by Zhang and Paxton, the energy and flux of electrons depend on the Kp index. As part of the photochemical approach various ways to solve the equations for the NO+, O2+ and N2+ ions are examined. Spatial and temporal distributions of molecular ions are compared with experimental data.
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WAVE-LIKE AURORAL ACTIVITIES PRECEDING SUBSTORM ONSET
Kornilova T.A., Golovchanskaya I.V.
Polar Geophysical Institute, Apatity, Murmansk region, Russia
Several types of wave-like auroral activities are observed at near-midnight MLT sector during substorm growth phase. They include (a) series of swirls-like intensifications propagating azimuthally along the distinct east-west (E-W) arc on the poleward boundary of the auroral zone; (b) multiple equatorward (or poleward) propagating E-W arcs splitting off the activated prebreakup arc; (c) azimuthally propagating bead-like intensifications inside the prebreakup arc immediately prior to substorm onset. Using ground-based optical data of Polar Geophysical Institute and THEMIS imager array, we study spatio-temporal characteristics of above mentioned wave activities and invoke to various theories to clarify their nature.
2D LINEARIZED MHD SIMULATIONS OF FLAPPING OSCILLATIONS
Korovinskiy D.B.1, Ivanov I.B.2,3, Semenov V.S.2, Erkaev N.V.4,5, Kiehas S.A.1
1 - Space Research Institute, Austrian Academy of Sciences 2 - Saint Petersburg State University
3 - Theoretical Physics Division, Petersburg Nuclear Physics Institute
4 - Institute of Computational Modelling, Russian Academy of Sciences
5 - Siberian Federal University
Kink-like magnetotail flapping oscillations in a Harris-like current sheet
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with earthward growing normal magnetic field component Bz are studied by means of time-dependent 2D linearized MHD numerical simulations. The results are compared with analytical estimates of the double-gradient model. It is found out that this model provides a reliable solution, when the current sheet parameters satisfy the model assumptions. The requirement of smallness of the Bz component is found to be the most severe restriction of the double-gradient model. The latter is found to be accurate enough for configurations with Bz up to values of 0.05 of the lobe magnetic field B0. For very small values of Bz ~0.01 B0 analytically predicted frequencies and perturbations of velocity demonstrate brilliant agreement with the results of numerical simulations. With growing Bz, profiles of perturbations get distorted and Fourier spectra of oscillations broaden; nevertheless, spectrum peaking frequencies stay close to the analytical predictions. Coupled with previous results, present simulations confirm that the earthward/tailward growth direction of the Bz component acts as a switch between stable/unstable regimes of the flapping mode, while the mode dispersion curve is the same in both cases. It is confirmed that flapping oscillations may be triggered by a simple Gaussian initial perturbation of the Vz velocity. Being localized in the vicinity of the sheet center, such initial kick may cause harmonic oscillations of the whole current sheet with a uniform across the sheet frequency.
ESTIMATION OF EFFECTIVE HEIGHT CHANGES OF EARTH-IONOSPHERE WAVEGUIDE USING PHASE
VARIATIONS OF LOW AND VERY LOW FREQUENCY RADIO SIGNALS DURING A SOLAR ECLIPSE
Korsakov A.A.1, Kozlov V.I.1,2, Karimov R.R.1
1 - Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS
2 - Noth-Eastern Federal University
During a solar eclipse, a lunar shadow covers the ultraviolet and X-ray radiation fluxes from the Sun - the main source of lower ionosphere
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ionization. Especially sensitive to the changes are low and very low frequency (LF: 30-300 kHz, VLF: 3-30 kHz) electromagnetic signals propagated by Earth-ionosphere waveguide. VLF-LF receiving enables lower ionosphere remote sensing. The effective height of the Earth-ionosphere waveguide is a parameter characterized a VLF signal phase. The waveguide effective height defined as the constant level of the ionosphere electron density along the VLF propagation path. A representation of the electron density profile as Chapman layer used to relate the effective height of the waveguide with an eclipse phase. The height changes represented as h = H*ln(I(Φ)/I(0)), where I(Φ) is a radiation flux, depending on a solar eclipse linear phase Φ, I(0) is a full daytime radiation flux, H is a normalization factor for the corresponding transmission path. It is supposed a single mode signal propagation and the effective height changes along the waveguide divided per 200 km element are the same. During the solar eclipse May 20-21, 2012 in Yakutsk by VLF-LF phase variations, the normalization factor is determined. The phase variations are 0.77 and 0.54 radians for the station signals JJY40 (40.0 kHz) and NPM (21.4 kHz) respectively. The normalization factors are 3.27 ± 0.08 and 2.27 ± 0.05 km for the propagation paths JJY40-Yakutsk and NPM-Yakutsk respectively. The effective height of the waveguide changing for the maximum shading JJY40-Yakutsk path (22:47 UT) is 4.63 km and 4.25 km for the maximum shading NPM-Yakutsk path (23:52 UT).
MAGNETOSPHERE-IONOSPHERE INTERACTION IN THE AURORAL REGION DURING SUBSTORM
ACTIVATIONS
Kozelova T.V.1, Kozelov B.V.1,2, Turyansky V.A.2
1 - Polar Geophysical Institute, Apatity, Russia 2 - Polar Geophysical Institute, Murmansk, Russia
Auroral vortex structures and dynamics of a plasma flow in the conjugated region in the equatorial plane of the magnetosphere were considered during two consecutive auroral activations occurred during a substorm on 19 December 2014 and separated one from another by 15 min. We used the
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ground-based auroral observations at the stations Apatity and Verhnetulomsk, the riometer absorption observations at the station Tumanny and the THEMIS-D satellite observations. The spacecraft was located at 7-9 Re in the outer region of the trapped energetic protons with the earthward plasma pressure gradient and observed the shear flow of plasma near the convection boundary of 10 keV electrons. Near this boundary, during both activations the spacecraft observed Pi2-like pulsations of magnetic field with period of 90 s. During the expansion phase the auroral vortex structures appear at the moments coincided with magnetic field dipolarization, increase of Pi2-like pulsation amplitude and energetic particle injection in space. At 30-50 s before these moments, the enhanced plasma flows were observed which can be identified as the beginning of plasma flow vorticity. This delay between the onsets of the space vortices and the optical aurora is consistent with the Alfvén transit time from the spacecraft locations to the ionosphere. We suppose that plasma flow vorticity is caused by the shear flow ballooning instability in the near-equatorial plane of the plasma sheet with the earthward plasma pressure gradient and the shear flow of plasma near the convection boundary.
NUMERICAL SIMULATIONS OF GLOBAL DYNAMICS AND PHOTOCHEMISTRY OF EARTH’S MIDDLE ATMOSPHERE. SOLAR ACTIVITY INPUT
Krivolutsky A.A.
Laboratory for Atmospheric Chemistry and Dynamics Central Aerological Observatory (CAO)
The results of three-dimensional numerical modeling of global distributions of temperature, circulation, ozone and other minor species of a terrestrial atmosphere, and also electronic concentration and the ionic components of area D of an ionosphere received by means of the global numerical models developed in laboratory of atmospheric chemistry and dynamics of the atmosphere of CAO of Roshydromet are provided. The description of models can be found in publications [1,2,3]. Numerical scenarios of
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influence of factors of solar activity are realized (UV solar variations and solar proton events). It is shown that the response to a solar cycle has not zonal character with an amplitude in several degrees in the troposphere, and strong proton events can lead to ozone depletion in the polar mesosphere and the upper stratosphere, owing to formation of additional molecules of oxides of nitrogen and hydrogen. [1] Krivolutsky A.A., Vyushkova T.Yu., Cherepanova L.A., Repnev A.I., Banin M. V. Three-dimensional global photochemical CHARM model. Accounting of a contribution of solar activity. Geomagnetism and aeronomy, Volume 55, No. 1, page 64-93, 2015. [2] Krivolutsky A.A., Cherepanova L.A., Vyushkova T.Yu., Repnev A.I. Three-dimensional global numerical CHARM-I photochemical model. The accounting of processes in the area D of an ionosphere. Geomagnetism and aeronomy, Volume 55, No. 4, page 483-503, 2015. [3] Krivolutsky A.A., Cherepanova L.A., Dementieva A.V., Repnev A.I., Klyuchnikova A.V. The global circulation of the atmosphere of Earth calculated by means of the ARM model. Accounting of a contribution of solar activity. Geomagnetism and aeronomy, Volume 55, No. 4, page 808-828, 2015.
SIMULATION OF THE UPPER ATMOSPHERE DISTURBANCES PRODUCED BY ACOUSTIC-
GRAVITY WAVES PROPAGATED FROM THE SOLAR TERMINATOR IN THE TROPOSPHERE
Kurdyaeva Y.A.1, Karpov I.V.1,2, Borchevkina O.P.1, Vasilev P.A.1, Kshevetskii S.P.1
1 - Immanuel Kant Baltic Federal University, Kaliningrad, Russia
2 - WDIZMIRAN, Kaliningrad
The numerical experiment results in perturbation of the upper atmosphere parameters due to the impact on the medium of the upward propagating acoustic gravity waves (AGW) excited in the lower atmosphere during the passage of solar terminator are represented. Our computations use a two-
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dimensional non-hydrostatic model of the generation and propagation of atmospheric waves; the model takes into account the processes of nonlinear wave interaction of propagated waves, dissipative processes. Atmospheric pressure variations at the lower boundary of the numerical model during the passage of the solar terminator (ST) is a source of wave disturbances. The characteristics of atmospheric pressure variations in these conditions are determined from the results of lidar sounding of the troposphere over Kaliningrad (52N, 22 E). The analysis of our lidar observations shows that the spectrum of variations in the lower atmosphere during ST periods has some peculiarities appeared to increase of the amplitude of parameter variations with the periods less than 20 minutes; and these variations are continued during ~ 1.5 hours after the terminator has passed. In the paper, the analysis of the computation results has shown that the upper atmosphere disturbances caused by the source considered, appear in strengthen of the parameter variations with the periods belonging to the AGW region. The paper discusses the revealed features of the frequency characteristics of the upper atmosphere disturbances. The work was supported by the Ministry of Education of the Russian Federation grant № 3.1127.2014/K, grants 15-05-01665.
RESONANT WAVE-PARTICLE INTERACTION OF SUPRATHERMAL IONS WITH LIGHTNING-
GENERATED ION CYCLOTRON WAVES
Kuzichev I.V.1, Shklyar D.R.1,2
1 - Space Research Institute of RAS 2 - Moscow Institute of Physics and Technology (State
University)
Lightning-generated emissions in ELF/VLF range play important role in ion dynamics in the low-altitude magnetosphere. In particular, lower hybrid waves excited by lightning discharges can interact resonantly with ions leading to efficient ion heating. Such an interaction takes place for ion energies much greater than thermal energy. Resonant interaction with ion cyclotron waves is considered as a preheating mechanism. There are two
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approaches to the description of resonant wave-particle interaction. The first is quasi-linear theory, which is applicable for the interaction with small amplitude wide spectrum waves, and the second is applied in the case of strong quasi-monochromatic waves. In this report, we discuss resonant interaction of ions with special ion cyclotron wave packets which do not correspond to any of these cases. Ray-tracing of ion cyclotron waves generated by lightning strokes shows that some wave packets get stuck in the region where the wave frequency becomes close to the local ion cyclotron frequency. Such wave packets are characterized by wave frequency and wave vector which vary in space and time and, thus, along particle trajectory. What is more, the wave vector increases linearly with time, so the wave eventually becomes quasi-electrostatic. We have considered such an interaction, derived the equations describing the motion of ions, and obtained the resonance condition. For suprathermal ions under consideration, the first cyclotron resonance gives the main contribution to the resonant interaction. The resonance condition for this resonance is defined by the detuning of the wave frequency from the local ion cyclotron frequency. Numerical results for the test particles and analytical estimates demonstrate the essential difference between the interaction under consideration and the case of wide spectrum waves described by quasi-linear theory. Whereas the latter leads to particle diffusion in the phase space, the interaction we study leads to preferential ion acceleration, with a non-diffusive character of ion energization. These results provide strong evidence that the acceleration of ions due to resonant interaction with these wave packets can be efficient for realistic wave field amplitudes. Naturally, such non-diffusive ion energization ensures the corresponding wave damping as well. Accordingly, the interaction under consideration provides a regular and efficient mechanism of ion energization in the low-altitude magnetosphere and, at the same time, accounts for the damping of ICW excited by lightnings.
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DEPENDENCE OF REGRESSION COEFFICIENT BETWEEN INTERPLANETARY AND
MAGNETOSPHERIC FIELD BY ON DATABASE SELECTION CRITERIA
Lukin A.S.1,2, Petrukovich A.A.2
1 - Faculty of Physics, Lomonosov University, Moscow 2 - Space Research Institute (IKI) RAS, Moscow
The azimuthal magnetic field component in the magnetotail By (in the east-west direction) is mainly determined by a similar component of the interplanetary magnetic field and magnetosphere dynamics. According to the observations of the Geotail project 1995-2005 we formed the database to analyze the impact of various factors on the magnetospheric Bym field. In this work we consider different models of the Bym as well as contributions of certain physical factors to the Bym for differing values of Bzi. The results show that the regression coefficient between Bym and Byi depends on the choice of a set of conditions for data analysis. A set composed only for satellite intersections of equatorial plane, includes more measurements madeat the southern interplanetary field, when the tail configuration is always changing. Set, consisting of long intervals of plasma sheet (equatorial zone) includes more measurements made in magnetically quiet period.
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IONOSPHERIC RESPONSE ON SPACE WEATHER EVENTS ON AN EXAMPLE OF DISTURBANCE OF
NOVEMBER 6TH 2001
Maltseva O.A.1, Sergeeva M.A.2,3
1 - Institute for Physics ,SFU, Rostov-on-Don, Russia 2 - Saint-Petersburg State University of Aerospace
Instrumentation 3 - SCiESMEX, Instituto de Geofisica, Mexico
One of problems of physics of the ionosphere and the magnetosphere is the study of distribution of ionization Ne in the plasmasphere, however there are not a lot of experimental opportunities. One of opportunities is the use of the total electron content ТЕС and the IRI-Plas model together with foF2 and plasma frequencies fne of satellites CHAMP and DMSP. In this paper, the event of November, 6th, 2001 for which in the literature there is a detailed analysis of influencing factors is considered. The basic attention is given to positive perturbations in the American sector for which cases of close flight of two satellites over the chosen stations were observed. To identify perturbations, global maps of ТЕС (dependence on a longitude for various latitudes) and latitudinal sections of fne(CHAMP) and fne(DMSP) for longitudes 60, 75, 90°W were calculated. N(h)-profiles were calculated to heights h(GPS) for 3 options of adaptation of the IRI-Plas model to: 1) median values of foF2, ТЕС, fne(CHAMP) and fne (DMSP), 2) instantaneous values of foF2, ТЕС, 3) instantaneous values of fne(CHAMP) and fne (DMSP) in addition to an option 2. It is shown that in most cases it is possible to coordinate all data and to obtain variations of Ne in topside and plasmaspheric parts of profiles in comparison with medians. Use of ТЕС allows to trace accurately character of perturbations and responsible areas, especially in cases when ТЕС and foF2 vary in an antiphase, however quantitative estimations of a response of the ionosphere lie within the factor 2-5 because of uncertainties of ТЕС and a fixed shape of N(h)-profiles in topside and plasmaspheric parts. This work was supported by SFU (grant 213.01-11/2014-22, O.A. Maltseva) and RFBR (grant _ 15-05-00856, M.A. Sergeeva)
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MODELING AND ANALYSIS OF COSMIC RAY VARIATIONS DURING PERIODS OF HELIOSPHERIC
DISTURBANCES
Mandrikova O.V., Zalyaev T.L.
Institute of Cosmophysical Researches and Radio Wave Propagation
We propose a new method of analysis of variations in the intensity of cosmic rays based on wavelets and their combination with neural networks. The method allows to allocate different scale anomalies in the variations of cosmic rays and measure their parameters (points of occurrence, duration, intensity) according to the data of neutron monitors. The method is sensitive to short-term small changes in temporal course of data and allows to perform in-depth analysis of variations of cosmic rays. Based on the method, we performed an analysis of the dynamics of cosmic rays during periods of increased solar activity and geomagnetic storms. During the analysis on the eve of the strong and moderate geomagnetic storms were allocated abnormal changes occurring a few hours before the initial phase of the storm. We thank researchers of the NMDB project (www.nmdb.eu/) for providing high-resolution neutron monitor data and those at Intermagnet (www.intermagnet.org) for promoting high standards of magnetic observatory practices. This research is supported by a grant of Russian Science Foundation No. 14-11-00194.
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ANALYSIS OF IONOSPHERIC PARAMETERS AND DETECTION OF ANOMALIES DURING
IONOSPHERIC STORMS
Mandrikova O.V.1,2, Fetisova (Glushkova) N.V.1, Polozov Yu.A.1,2
1 - Institute of Cosmophysical Research and Radio Wave Propagation (IKIR FEB RAS)
2 - Kamchatka State Technical University
Research of ionospheric parameter variations during the periods of increased solar activity and geomagnetic storms was carried out applying the data of ground station networks (ionospheric critical frequency data (foF2) at Paratunka (Kamchatka peninsula), Gakona (USA) and Kokubunji (Japan) stations were analyzed). The response of the ionosphere to geomagnetic storms is a very complex phenomenon, which is called ionospheric storm. It may consist of positive and negative phases having complex spatial and temporal distribution. In the present paper a comprehensive approach based on a combination of wavelets with classical autoregressive methods and neural networks was used for the research. In the earlier works the authors demonstrated the efficiency of this approach for the analysis of ionospheric parameters and detection of anomaly during increased solar activity and geomagnetic storms. The advantage of the approach in comparison with the traditional methods of ionospheric data analysis is the opportunity to receive higher precision estimates of the moments of occurrence, time duration and intensity of ionospheric anomalies. During the research, large-scale anomalous increases of ionospheric parameters in comparison with the background level (positive phase of ionospheric storms) were determined in the analyzed areas for a few hours before the beginning of geomagnetic storms. Detected anomalous effects lasted from a few hours to half a day. During strong geomagnetic storms, the electron density in the ionosphere greatly decreased, and long negative phases of ionospheric storms occurred. This work was supported by a grant of the Russian Scientific Foundation №14-11-00194.
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COMPARATIVE ANALYSIS OF THE QUALITY OF PREDICTION FOR FLUENCES OF RELATIVISTIC
ELECTRONS OF THE OUTER RADIATION BELT OF THE EARTH AT DIFFERENT PHASES OF THE SOLAR
ACTIVITY CYCLE
Myagkova I.N., Dolenko S.A.
Lomonosov Moscow State University, Skobeltsyn Institute of Nuclear Physics
The forecast of radiation environment at geosynchronous orbit (GEO) near the boundary of the Outer Earth’s Radiation Belt (OERB) is very important due to the large number of satellites populating this region. Relativistic electrons of the outer ERB are even called "killer electrons" since they can damage the electronic components of spacecraft. The flux of the electrons with the energy >2 MeV at GEO orbits is very unstable within time intervals about days and even hours. It shows a strong temporal dependence on epoch of solar activity (SA) relative to the onset of geomagnetic disturbances (AE-min and AE-max models). Any generally accepted theory that explains all the features of the experimentally measured behavior of outer ERB is not created, so the statistical methods are usually less dependent on the selected physical models, it is useful to have an effective forecasting model based on statistical methods. Artificial neural networks (ANN) model that would work as good or better than any other statistical model. The intensity of the OERB depends on the values of the components of interplanetary magnetic field, on solar wind, and on geomagnetic storms. It is known that all of these values are strongly dependent on SA cycle phase. We have already created an ANN prediction model for hourly average values of the electrons of OERB at GEO with prediction horizon from 1 to 12 h (R2=0.98 and 0.86) using data without dividing it by the level of SA. The hypothesis that separate networks trained for different phases of SA would be more successful than the single network using the whole data for the overall cycle has been checked in presented study. This study was supported by the Russian Science Foundation, grant № 16-17-00098.
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MONITORING OF PLANETARY PERTURBATIONS IN THE D - REGION OF THE IONOSPHERE BY RADIO
OCCULTATION METHOD
Nagorskiy P.M.1, Lemeshko E.Yu.2
1 - Institute of monitoring of climatic and ecological systems SB RAS
2 - Tomsk Polytechnic University
D-region is the least explored region of the ionosphere which is effectively influenced by both natural (terrestrial and space) and man-made factors. For this region of the ionosphere, unlike other ionosphere areas, there exist no methods and means of planetary diagnostics and control. The main directions of the monitoring of regular and sporadic layers of the ionosphere by the radio occultation method on a system of transmission paths "satellite-satellite" are summarized in [1]. In [2] we proposed a method for the global assessment of the state of the domain D and the base of E region of the ionosphere by the space-based means, that is formed on the analysis of the differential absorption of radio waves of ordinary and extraordinary polarization in the lower ionosphere. Besides, a model analysis of satellite ionospheric sounding data in the frequency band higher than the cutoff fxF2was carried out. The paper discusses possible ways of electronic registration Ne concentration in the D-region on a global scale, based on a comparative evaluation of the amplitudes of circularly polarized components of linearly polarized signal, which is distributed on a system of radio paths "satellite-satellite" crossing the region D. For various heliogeophysical conditions we determined the boundaries of the frequency band, which can assess Ne perturbations in the D-area.
1. Yakovlev OI, Paveljev A.G, Matyugov S.S. Remote sensing of the Earth. Radio occultation monitoring of the atmosphere and ionosphere. - M .: LIBROKOM, 2010. - 208 p.
2. Zuev V.V, Nagorskiy P.M. The method of assessing the state of D ionospheric space-based radio equipment // Study of Earth from space. - 2011. - № 4. - pp.33-40
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COMPARATIVE ANALYSIS OF THE LONG-PERIOD VARIATIONS OF IONIZING RADIATION AND ATMOSPHERIC ELECTRICAL QUANTITIES
Nagorskiy P.M.1, Pustovalov K.N.1, Smirnov S.V.1, Yakovleva V.S.2
1 - Institute of monitoring of climatic and ecological systems SB RAS
2 - Tomsk Polytechnic University
The aim of this work is to study variations of ionizing radiation of the terrestrial of space origin, together with atmospheric-electrical disturbances and variations of meteorological variables in the conditions of middle latitude and sharp continental climate. For the analysis the meteorological and atmospheric-electrical data of IMCES SB RAS, data on the neutron component of galactic cosmic rays (Novosibirsk region., Observatory 'Kljuchi') and data on the level and variations of the background component of the ionizing radiation (TPU) were used. The focus is on the identification of coordinated variations in the time intervals from synoptic to annual. During the investigations we excluded the time intervals with "disturbed weather" from the input data. The terms of "undisturbed (fine) weather" were defined as events with lack of precipitation, including fog, blizzards, low-level clouds (clouds of the upper layer not more than 3 points), and the wind speed - less than 6 m/s. This condition allowed to reduce significantly the dispersion of the original data, associated, as a rule, with cumulonimbus clouds, precipitation and thunderstorms. For a synoptic scale there is a close correlation between the change in the level of the neutron component of space rays and γ- background variations of terrestrial origin. As a result, the cyclonic activity and the associated changes in atmospheric pressure leads to a consistent fluctuations of level γ- background of terrestrial origin. Also, the reorganization of atmospheric circulation over large areas associated with global climate change leads to the consistent changes in the level of natural ionizing radiation of terrestrial and space origin. A minimum flow of the neutron component of space rays
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with an annual period coincides with the beginning of the calendar year, while the minima of γ- and β- background levels of ionizing radiation component falls at the end of the first quarter.
NUMERICAL UPPER ATMOSPHERE MODEL (UAM) - HISTORY, CURRENT STATE, PERSPECTIVES
Namgaladze A.A.
MASU, Murmansk
Upper Atmosphere Model (UAM) is the global, 3D, selfconsistent, time-independent numerical model, describing mesosphere, thermosphere, ionosphere, plasmasphere and inner magnetosphere of the Earth as unite system from the heights 60-80 km (lower boundary is given by user) up to the geocentric distance of 15 Earths radii (100 000 km). Solving system of the basic equations, describing particles, momentum and energy conservation, model calculates 3D distributions of the concentrations of the neutral (O, O2, N2, H) and charged (electrons and ions O2
+, NO+, O+, H+) particles, temperatures of the neutral gases, ions and electrons, their motion velocities, and as well the electric potential and electric field vector components for any geo and heliophysics conditions. This model is better than any existing foreign and native analogues on the height range and horizontal resolution. It was created in Kaliningrad on the basis of several more simple models united into the global selfconsistent model of the thermosphere, ionosphere and protonosphere (GSM TIP). At the Polar Geophysical Institute and Murmansk State Technical University the model was modernized for the highlatitude ionospheric effects' studies and was named as UAM. In particular, the empirical models of the ionosphere, thermosphere and neutral winds have been included into the model for comparing with observations, аs well as the numerical algorithms of the model equations' solution with the variable latitudinal integration steps have been realized for studies of the thermospheric and ionospheric effects with spatial scales more than 100 km. Using the UAM, there was realized the mathematical modeling of large amount of the specific geophysical cases, and on the basis of these model calculations there have been given the physical interpretation of the
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incoherent scatter radars and ionospheric radiotomography odservation results. Ionospheric effects of the large seismic events' preparation have been studied using the UAM at the last time. The UAM has been actively used not only in Murmansk but as well in Sankt Petersburg, Potsdam (Germany) and Toronto (Canada). In the last organization (York Univertsity) the UAM has been united with the Canadian Iononsphere and Atmosphere Model. At present the UAM is used for the natural and technogenic catastrophes' studies as in the global scales (ionospheric earthquakes' effects) as well especially for the Arctic (auroral, subauroral and polar phenomena). This determinates the basic future UAM development directions: 1) including into the UAM total global electric suit taking into account the thunderstorm and seismogenic electricity and 2) transition to the real magnetic field in the UAM. Various descriptions of the UAM history, parts and details can be found at the sites a.namgaladze.tripod.com uammod.wordpress.com
LOCALIZATION OF IONOSPHERIC PC4 SOURCES AND PROTON EMISSIONS DURING MAGNETIC
PULSATIONS PC1 TYPE OF PEARLS INTENSIFICATIONS
Petlenko A.V.
SPbF IZMIRAN
In the period 01.09-10.09 2012 to the east of the IMAGE magnetometers network the field of geomagnetic pulsations were measured by 7 magnetovariational stations, 5 of which were densely (every 70 km), located on the profile, was being oriented along the geomagnetic meridian Λm~112° in a latitude band Фm~59-62° and allowed to register the disturbance field in the range of 0.003-3 Hz with a threshold sensitivity <10-3 nT/Hz1/2. 09.09 2012 at 10:00-15:00 UT these stations recorded periodic intensification of Pc1 geomagnetic pulsations type of pearls, which
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repetition rate of ~120 s to coincide with the period of oscillation of Pc4 pulsations were being observed simultaneously. On the field distributions Pc4 built on the results of measurements of the entire set of stations in the vicinity of the profile of the two types of features have been selected. The features of type 1 localization regions are determined by the differences of the field > 0.01 nT, behave consistently, reflecting periodic changes of Pc4 field. The form as well as the position and the size of areas of localization features such as two, determined by differences of field < 0.01 nT change for about 10 seconds. Features of type 2, localized areas within 20-70 km in size, appear in the vicinity of the profile during activation Pc1 only. In terms of current models had been built it was found that, together with the features of type 1 especially type 2, are localized in large areas could be formed by ionospheric current Pc4 pulsation system, the unstable behavior of the latter features is due to redistribution of the intensity of local ionospheric Pc4 sources. The currents of area features of types 2 of smaller localization are formed offset from Pc4 sources, and representing, apparently, local proton emissions associated with the activations of Pc1 pulsations. In this way, it is possible to find the position of the localized proton emissions associated with the intensification of this type of pulsations, estimate the relative change in their intensity and propagation velocity of these changes that creates the preconditions for a better understanding of the physical nature of Pc1 geomagnetic pulsations.
MULTIPOINT STUDIES OF 2D MAGNETOTAIL CURRENT SHEET
Petrukovich A.A.1, Artemyev A.V.1, Zelenyi L.M.1, Vasko I.Y.1, Nakamura R.2
1 - Space Research Institute 2 - Space Research Institute, Graz
CLUSTER, Geotail, Themis projects provide unique tools for magnetotail current sheet studies at a wide range of downtail distances: multipoint curlometer allows to measure electric current density, whereas regular
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electron data contains information on largescale tail structure. Observations show that moderately thin ion-scale embedded sheet is formed during substorm growth phase. Comparison of curlometer with particle data helps to estimate contributions of transient and magnetized ions as well as electrons to current density. Thin intense sheet with sub-ion scale is appearing after onset near reconnection zones, but vertical pressure balance requirement substantially limits the possible range of sheet thickness. We present the review of our recent findings for current sheets in various environments.
CHARACTERING THE GEOMAGNETIC FIELD VARIABILITY FOR THE STUDY OF MAGNETIC STORM IMPACT ON ELECTRIC POWER LINES
Pilipenko V.A.1, Belakhovsky V.B.2, Sakharov Ya.A.2
1 - Geophysical Center, Moscow, Russia 2 - Polar Geophysical Institute, Apatity, Russia
The geomagnetically induced current (GIC) intensity is determined by variations of geomagnetic field. Predominantly geomagnetic field disturbances are oriented in the N-S direction, and produced by the E-W ionospheric currents. Thus, such disturbances seemingly will not induce any significant GIC in a latitudinally-oriented system. However, during magnetic storms GIC in power systems elongated in the N-S direction were quite significant. We apply to the geomagnetic data from magnetometer array various techniques to characterize the geomagnetic field variability: vector mapping of time series, and a measure of time variations of vector angle cosines. This technique has shown that ionospheric currents fluctuate not just in E-W direction, but chaotically in both E-W and N-S directions. In this paper we examine the relative contribution of various geomagnetic disturbances (SC, storm onset, Pc5 pulsations) into enhancements of GIC using data from GIC-recording system deployed by Polar Geophysical Institute and IMAGE array of magnetometers.
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SIMULTANEOUS OBSERVATIONS OF THE IAR EMISSIONS ALONG A MERIDIAN
Polyushkina T.N.1, Pashinin A.Yu.1, Rakhmatulin R.A.1, Tsegmed B.2, Potapov A.S.1
1 - Institute of Solar-Terrestrial Physics SB RAS, Irkutsk, Russia 2 - Institute of Astronomy and Geophysics MAS, Ulaanbaatar,
Mongolia
We offer the observations of the IAR emission made the first time simultaneously at three stations using identical induction magnetometers. The stations are located along the same meridian, two of them are mid-latitudinal; the third one is situated in the auroral zone. We compare the main features of the observed multi-band emission (frequency, amplitude, and frequency difference between adjacent harmonics) with ionospheric parameters measured at the stations using ionosondes and GPS observations. Diurnal variations of the ionospheric and ULF emission characteristics are also compared. The results show that there is quite a reliable connection between the resonant frequencies of the resonator bands and the critical frequency of the F2 layer of the ionosphere, namely, the frequency of the IAR emission varies inversely as the critical frequency of the ionosphere. This is due to the fact that the frequency of oscillation captured in the resonator is primarily determined by the Alfvén velocity (which depends on the plasma density) in the ionospheric F2 layer. The correlation varies at different stations; at the high latitudes it is smaller, but is generally well observed along the whole meridian. This gives hope for the opportunity to develop a method for evaluating the critical frequency of the F2 layer of the ionosphere according to ULF observations in the 0.5–10 Hz frequency range. This method is particularly in demand for the high latitudes, as there is often not possible to measure the critical frequency by conventional methods due to significant disturbances. The work was supported by the Russian Science Foundation, grant 14-37-00027; the part of the work made by T.N.P. and B.Ts. (observations and analysis of data) was supported by RFBR grant 16-05-00631.
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THE QUASI-BIENNIAL CYCLE OF SOLAR ACTIVITY AND DYNAMO THEORY
Popova E.P., Yukhina N.A.
Skobeltsyn Institute of Nuclear Physics, Lomonosov Moscow State University
Solar magnetic activity has huge impact on space weather and space climate. The cyclic magnetic activity of the Sun is believed to have a main period of about 22 years. However, more careful studies have shown that the solar cycle is more complex. A large number of works where quasicyclic impulses of magnetic activity were shown to emerge with periods of about 0.5–2.0 years against the background of the 22-year solar cycle have appeared in the last decades. Such two solar cycles affect the flux of galactic cosmic rays. We have investigated the behavior of solar magnetic field within the framework of a one-dimensional nonlinear αω-dynamo by taking into account the thickness of the convective zone, turbulent diffusivity, and meridional circulation. We show that there exists a regime in the model where short and longer patterns are simultaneously observed in the butterfly diagrams for the magnetic field. This regime is similar to the mixed cycle of the Sun, when fast quasi-biennial oscillations are observed against the background of the 22-year cycle. Our numerical analysis showed that a regime of mixed oscillations similar to that observed is reproduced at realistic model parameters. It is shown how the layer thickness has an effect on the threshold value of the dynamo number necessary for generating the oscillating magnetic field. We investigated dynamo model with two layers and found conditions for existing quasi-biennial oscillations and 22-year cycle.
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COMPARISON OF EMIC WAVE OBSERVATIONS IN THE NEAR-EQUATORIAL REGION OF THE
MAGNETOSPHERE AND PRECIPITATION OF ENERGETIC PROTONS AT LOW ALTITUDES
Popova T.A.1, Yahnin A.G.1, Demekhov A.G.1,2
1 - Polar Geophysical Institute, Apatity 2 - Institute of Applied Physics RAS, Nizhny Novgorod
We study conjugacy of the generation region of EMIC waves with energetic proton precipitation by using wave data from THEMIS spacecraft and energetic proton data from low-orbiting NOAA POES and MetOp satellites. For this study we developed a plugin for SPEDAS software ensuring proper comparison of the observations onboard magnetospheric and low-altitude spacecraft. The plugin calculates the projections of spacecraft orbits on the ionospheric altitude (100 km) in the SM coordinate system (by using the IGRF model for low-altitude spacecraft and different versions of the Tsyganenko models for magnetospheric spacecraft). For close projections the latitudinal distributions of the compared parameters from different spacecraft are built. In our case, these parameters are the precipitated energetic proton fluxes measured by the NOAA POES and MetOp, and EMIC wave intensity from THEMIS. The wave intensity is calculated separately for H+ and He+ bands. The frequencies corresponding to the maximum spectral amplitudes of the waves are determined in each band. The latitudinal distribution of the density of the cold plasma in the magnetosphere is built where possible. The conjugacy of the regions of EMIC wave generation and energetic proton precipitation is most clearly seen for the events related to quasi-monochromatic Pc1 emissions whose source does not change its latitudinal position for sufficiently long time. We show that the proton precipitation accompanies the EMIC wave generation in both He+ and H+ bands. In this case, the EMIC waves below/above the He+ gyrofrequency usually occurs in the plasmasphere/outside the plasmapause.
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THIN STRUCTURE OF THE CIR SHEAR ZONE
Potapov A.S.1, Ryzhakova L.V.2
1 - Institute of Solar-Terrestrial Physics SB RAS 2 - Irkutsk National Research Technical University
We analyze data from satellite measurements of the magnetic field and the plasma at the ACE apparatus from 30 events of corotating interaction regions (CIR) for 2002–2010., that is, for a period of decline and minimum of solar activity of the 23rd solar cycle. We use the 64-second measurements of SW data on plasma velocity, density of protons and alpha particles, temperature of the proton component, and 16-second measurements of the interplanetary magnetic field (IMF) vectors which are then averaged to 64-second values for the docking with plasma measurements. In addition, for specific periods, we used a 1-second measurement data of the interplanetary magnetic field. Basing on these data we calculated statistics of occurrence and main characteristics of high-beta current and plasma sheets within shear structure of CIR streams. . In our 30 selected CIR events, we found 127 current sheets with current density more than 0.12 A/m2 and only 41 high-beta sheets with β > 5. A CIR passage through the magnetosphere was studied. It is shown that stream magnetic structure is saved in spite of noticeable distortion. Trailing part of the CIR stream was exposed to strong corruption. The work was supported by RFBR grants 16-05-00631 and 16-05-00056.
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NARROW-BAND EMISSION WITH VARYING FREQUENCY FROM 0.5 UP TO 3.5 HZ IN THE
BACKGROUND OF THE MAIN PHASE OF THE 17 MARCH 2013 MAGNETIC STORM
Potapov A.S.1, Dovbnya B.V.2, Baishev D.G.3, Polyushkina T.N.1, Rakhmatulin R.A.1
1 - Institute of Solar-Terrestrial Physics SB RAS 2 - Borok Geophysical Observatory of IPhE RAS
3 - Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy SB RAS
We present results of the analysis of an unusually long narrow-band emission in the Pc1 range with increasing carrier frequency. The event was observed against the background of the main phase of strong magnetic storm caused by arrival of the high-speed solar wind stream with a shock wave in the stream head and a long interval of negative vertical component of the interplanetary magnetic field. Emission of approximately 9-hour duration had a local character, appearing just at three stations located in the range of geographical longitude λ = 100°–130° E and magnetic shells L = 2.2–3.4. The signal carrier frequency grew in a stepped mode from 0.5 to 3.5 Hz. An emission interpretation based on the standard model of the generation of ion cyclotron waves in the magnetosphere due to the resonant wave-particle interaction with ion fluxes of moderate energies is proposed. It is supposed that a continuous shift of the generation region, located in the outer area of the plasmasphere, into smaller L-shell is able to explain both the phenomenon locality, and the range of frequency increase. A narrow emission frequency band is associated with the formation of the nose-like structures in the energy spectrum of the ion fluxes penetrating from the geomagnetic tail into magnetosphere. A possible speculative scenario of the processes leading to the generation of the observed emission is proposed. The scenario contains specific values of the generation region position, the plasma density, magnetic field and the resonant proton energies. We discuss the morphological differences of the considered emissions from known
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types of geomagnetic pulsations and the reasons which led to the appearance of this unusual event. The work was supported by Russian Foundation for Basic Research, grants 16-05-00631, 16-05-00056, and 15-45-05108.
THE UPWARD TREND IN GEOMAGNETIC STORM OCCURENCES DURING THE 20th CENTURY
Ptitsyna N.G., Soldatov V.A., Sokolov S.N., Tyasto M.I.
SPbFIZMIRAN, St. Petersburg, Russia
We analyzed 1305 geomagnetic storms registered in St. Petersburg observatories (Pavlovsk/ Slutsk and Voeikovo) in 1878-1954 (cycles 12-18). The focus was on geomagnetic storms with sudden commencement Ssc and storms with gradual commencement Sg. We found an increase of occurrence frequency of all types of storms in the period under study. Starting from ~1900 the number of storms/cycle (total storms, Ssc and Sg) is increasing. From cycle 14 to cycle 18 the number of Ssc storms/cycle increased by 2,93, and of Sg by 1,43. The relative contribution of Ssc and Sg storms to the total number of storm occurrence shows a systematic evolution starting from cycle 13. The percent of Ssc storm occurrences is gradually increasing (from 18% in cycle 13 to 34% in cycle 18), i.e. percent of Ssc storms/cycle almost doubled in the first half of the 20th century. Sg percentage decreased from 82% to 66% during the same period. It has been previously supposed that Ssc storms were associated with coronal mass ejections (CME) and Sg with corotating interaction regions (CIR). CME and CIR are related to different kind of magnetic fields on the Sun: closed and open configurations. It seems that our result indicate that the activity of both types of solar magnetic configurations raised during ~ 1900-1954, however for closed magnetic structures this increase occurred more rapidly in comparison with open magnetic field structures. It can be concluded that open and closed solar magnetic fields have a differential time evolution at least during the first half of the 20thcentury.
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THE 22-YEAR CYCLE OF AURORA BOREALIS EVENTS IN THE 19th CENTURY
Ptitsyna N.G., Tyasto M.I., Khrapov B.A.
SPbFIZMIRAN, St. Petersburg, Russia
Analysis of the Russian meteorological network data in the period 1837-1909 revealed the 22-year variation in the annual frequency of aurora borealis occurrences N. Moreover, characteristics of the 22-year periodicity depend on geomagnetic latitudes Φ. In mid latitudes (Φ<56°) during three years in the end of even-numbered cycles N is higher than in odd cycles. For high-latitude auroras (Φ≥56°) the pattern is reversed: in the end of odd cycles N is higher than in even cycles. High-latitude aurora events show an asymmetry in polar cycles (which run from a sunspot maximum to the next maximum): increased N in odd polar cycles (beginning at maximum in odd cycles) in comparison with even cycles. This increase in high-latitude auroral events in odd polar cycles testifies to the increased geoeffectivenes in this period of high-speed streams, which control the high-latitude auroral activity. Our results indicate that the most geoeffective high-speed streams were emitted during periods when the solar polar magnetic fields in the northern hemisphere were negative.
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HISTORIC AURORA BOREALIS OBSERVED IN ITALY AND RELATED SOLAR AND GEOMAGNETIC
ACTIVITY
Ptitsyna N.G.1, Altamore A.2,3
1 - SPbFIZMIRAN, St. Petersburg, Russia 2 - University “Roma-Tre”, Phys. and Math. Department, Rome,
Italy 3 - Inaf-Astronomical Obs. of Rome, Italy
Visibility of aurora borealis strongly depends on the latitude of the observer’s location. Geomagnetic latitudes of Italia : approximately 27° < Φ < 38°. At such low latitudes aurora displays are relatively rare and they are usually associated with very strong geomagnetic storms. Recently attention was drawn to other type of auroras which were observed under low or middle geomagnetic activity and which were not associated with geomagnetic storms, so-called “sporadic auroras”. Data on sporadic auroras are sparse, especially for Europe. In this work we present some historical records of aurora borealis that are not widely known, if any. In these records both type of auroras are registered. We add some notable auroras observed in Italy in 18th century and in more recent times to well-known lists of great auroras. We also present data on 22 aurora borealis that were registered in 1938-1978 in the North of Italy, in Trentino region. Among them 16 auroras could be classified as sporadic auroras. We studied solar cycle distribution of aurora events of this dataset and of auroras registered in 1781-1789 in Rome, Bologna and Padua.
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IMPACT OF THE INTERPLANETARY MAGNETIC FIELD ON FLOW AHEAD OF THE EARTH'S
MAGNETOSPHERE ON IMPINGEMENT OF A SOLAR WIND DISCONTINUITY
Pushkar E.A.
Engineering University, Moscow, Russia
The solution of the magnetohydrodynamic (MHD) Riemann problem of breakdown of an arbitrary discontinuity is used to construct a 3D pattern of the impact of a strong solar wind discontinuity (shock wave, rotational or contact discontinuity) on the Earth's bow shock and magnetosheath when the interplanetary magnetic field is taken into account in the 3D non-plane-polarized formulation within the ideal MHD model. The interaction pattern is constructed as a mosaic of exact solutions obtained on computer using an original 3D MHD Riemann solver developed for the Riemann problem of breakdown of an MHD discontinuity between the states of the medium at a point on the Earth's bow shock at which the impinging discontinuity is located at a given instant. The general flow pattern is a function of the angular coordinates (latitude and longitude) of points on the bow shock. The main features of the problem considered are the restructuring of the wave flow pattern when the discontinuity propagates along the flanks of the Earth's bow shock, the absence of continuous dependence of the solution on the constitutive parameters, and appearance of jumps in density, pressure, and magnetic field strength when the characteristic velocities (Alfvénic and slow magnetosonic) coincide in flow and the corresponding waves (Alfvén discontinuities and slow shock or rarefaction waves) merge with each other. The investigations can be used to interpret spacecraft's measurements in the solar wind and in the magnetosheath. For example, it is shown that fairly narrow zones can exist on the Earth's shock in which the density and the pressure increase more strongly in fast waves and decrease in slow rarefaction waves, as compared with the neighboring regions, while the magnetic field strength increases in both waves. Thus, spacecraft closely located in space may observe quite different plasma parameters.
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The work was carried out with support from the Russian Foundation for Basic Research (project No.~ 14-01-00335).
CAN MHD MODELS DESCRIBE MAGNETOSPHERIC CONFIGURATION AND DYNAMICS REASONABLY
WELL?
Samsonov A.A.
St. Petersburg State University, Russia
From the end of last century, global MHD models have been actively used to reproduce magnetospheric structures and dynamics. The MHD approach has both advantages and limitations. First, we present a new global MHD model developed at the St. Petersburg State University. Second, we show examples of using MHD models for predictions: global magnetospheric parameters and temporal variations in selected events, magnetospheric-ionospheric currents and ground variations. Finally, we discuss future ways of development of MHD models in magnetospheric studies and possible connections with other models.
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PREDICTION OF MAGNETOSPHERIC EXPANSION DURING RADIAL IMF INTERVALS USING GLOBAL
MHD MODEL
Samsonov A.A.1, Sibeck D.G.2, Nemecek Z.3, Safrankova J.3
1 - St. Petersburg State University, Russia 2 - NASA Goddard Space Flight Center, USA
3 - Charles University, Prague, Czech Republic
Spacecraft observations published by several authors demonstrate large magnetospheric expansion during long-lasting intervals with quasi-radial interplanetary magnetic field (IMF). This expansion is related to decrease of solar wind dynamic pressure which has also been observed in the magnetosheath during these intervals. We suppose that the reason of the pressure decrease is changes of solar wind parameters in the foreshock cavity. Based on previous statistical results we suggest that the density and velocity in the foreshock cavity decrease to ~60 % and ~94 % of the respective ambient solar wind values when the IMF cone angle falls below 50 degrees. We have changed upstream boundary conditions in a global MHD model and show that the modified model predicts magnetopause distances close to those observed by THEMIS.
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PROCESSES AT THE BOW SHOCK AND AT THE TRANSITION LAYER
Sedykh P.A.
Institute of Solar-Terrestrial Physics, Lermontov str. 126a, Irkutsk, 664033, Russia
Interest to research processes in BS region has strongly increased recently. The BS front is the main converter of SW kinetic energy into the gas dynamic energy, electromagnetic energy and so on [Sedykh P.A. Bow shock: Power aspects.// Advances in Space Research, Elsevier Science., JASR11746, 2014]. The solar wind energy fuels also the ions acceleration process, the generation of waves in the region in front of the BS, and the energy that is needed for building up the foreshock. It is interesting to see the Poyting flux value and to estimate the ratio of the energy flux carried by the waves to the kinetic energy flux of the incident SW. The whistler waves upstream may also be excited by electron cyclotron resonance. Different frequencies are due to the lower magnetic field value and lower densities in the BS upstream region. For example, one can clearly see that only a very small portion of the SW energy dissipates into the whistler waves, typically 0.1%. More events are necessary to consider for studying the wave phenomena in the Earth’s BS region in detail. The Perreault-Akasofu formula, which adequately described the relation between the SW parameters and geomagnetic disturbance, evidently indicated that the electromagnetic part of the total SW energy is used. The Perreault-Akasofu formula is still successfully used (although is criticized) as a convenient empirical block in practical calculations. When passing through the BS front, the intensity of the tangential component of the SW magnetic field and the plasma density increase several fold. Therefore, among other things, the BS front is a current sheet. The current is diverging in this layer, i.e. the front is the generator of the electric current. Since plasma with magnetic field passes through the front, electric field arises in the front reference system. Thus, the BS front is a source of electric power. This electric power is distributed between two consumers - the Transition Layer (TL) and the magnetosphere. The TL may only conditionally be classed as a ‘consumer’, because in a certain mode the TL can act as a generator.
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There is a potential difference between the BS front and the magnetosphere, unequivocally (since the TL magnetic field is determined by the SW magnetic field) associated with the velocity of the transition layer plasma flow. Thus, the magnetopause potential is functionally related to SW parameters. It is clear that the primary energy source for magnetospheric processes is the SW, but the process of energy transfer from the SW into the magnetosphere, or rather, to convecting magnetospheric plasma, appears to be rather complicated.
MAGNETOSPHERE-IONOSPHERE COUPLING DURING A SUBSTORM
Sedykh P.A.
Institute of Solar-Terrestrial Physics, Lermontov str. 126a, Irkutsk, 664033, Russia
The combined action of convection and pitch-angle diffusion of electrons and protons is responsible for the formation of gas pressure distribution in the magnetosphere [Ponomarev E.A., 1985], that is, steady bulk currents. The divergence of these bulk currents brings about a spatial distribution of field-aligned currents, i.e. magnetospheric sources of ionospheric current systems. It is known [Ponomarev, 1985] that the contents of the magnetic flux tube (plasma tube - PT) transfers from one magnetic flux tube to another in the plasma convection process (associated with processes in bow shock region –[Sedykh P.A. Bow shock: Power aspects. Nova Science Publ. NY USA, in Horizons in World Physics. 285. ISBN: 978-1-63482-826-0; P. 1-67. 2015]) without surplus and deficiency in the case where the field lines of the magnetic flux tube are equipotential ones. This idealization is quite realistic everywhere apart from polar auroras. The PT drifting toward the Earth in a dipole field, its volume decreases, and the situation is the reverse for density, while pressure increases. However, the process of adiabatic compression is attended by the processes of PT depletion due to pitch-angle diffusion into the loss cone. The gas pressure has a maximum on each line of convection. A typical gas pressure pattern (3D) that results through the combined action of convection and loses has the form of an amphitheater with a clearly pronounced maximum near the
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midnight meridian, and with a sharp earthward “break”. The projection (mapping) of such plasma pressure relief onto the ionosphere corresponds to the form and position of the auroral oval. This projection, like the real auroral oval, executes a motion with a change of the convection electric field, and expands with an enhancement of the field. In this process the amplitude at a maximum increases as the inner edge of the plasma sheet approaches the Earth. Knowing plasma pressure distributions, we can determine the locations of the MHD compressor and MHD generators in the magnetosphere. Unfortunately, direct observations of the plasma distribution in the magnetosphere are associated with great difficulties, because throughout the nighttime side of the magnetosphere, it is necessary to know the plasma pressure with high resolution, which in situ satellites have been unable to provide. As shown by Waters et al., a map of global field-aligned currents can be constructed with hourly resolution using magnetometer data from the Iridium System consisting of 66 satellites in circular polar orbits. Multisatellite projects are under active development and are necessary, but similar project would be a very expensive mission. Therefore, it becomes necessary to simulate processes in the near-Earth space, and it is important only to correctly choose and apply the initial system of equations. Perhaps the mystery of a substorm lies in the distribution of plasma pressure, or more precisely, in the global redistribution of plasma pressure in the nighttime side of the magnetosphere with a southward IMF Bz component.
FEATURES OF THE MOTION OF THE NORTH MAGNETIC POLE
Semakov N.N.1,2, Grigorevsky A.V.1, Kovalev A.A.2, Fedotova O.I.2, Pavlov A.F.1,2
1 - Novosibirsk State University 2 - Geophysical Service of RAS
The aim of this work was to assess the direction and speed of the true magnetic North pole during the instrumental magnetic measurements . Most information was obtained from Weinberg directory containing
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magnetic determination on the territory of Russia and adjacent countries from 1556 to 1925. In subsequent years, was used mainly values of declination and inclination at magnetic observatories, as well as at points a century of progress, drifting stations, and other specially organized Arctic routes, including with the participation of the authors. As a result of this work it was found that a characteristic feature is the shift in the location of the wandering virtual, that is, the actual or estimated magnetic North pole from the Canadian Arctic archipelago to the archipelago of Severnaya Zemlya. This suggests it is likely expressed by both the Canadian and Russian magnetologists assumptions about the possibility of approaching the true magnetic North pole to the Russian coast in the coming century. It should be noted that, despite a common trend in the age-old movement, the spatial location of the virtual magnetic poles in the same era observatories in the Eastern and Western hemispheres is significantly different. When the total elongation of the region of location of these poles approximately along the great circle arc connecting the epicenters of the Canadian and Siberian world magnetic anomalies, in all of the examined era in "Canadian" part of this region are located predominantly magnetic poles of the observatories in North America and Greenland, and in "the Siberian" - Europe and Siberia. As for the speed of the "own" movement of the virtual magnetic poles, in his continuous movement of these poles as during the day and over longer and shorter intervals describe the loops of different scales. Thus the speed of movement of the virtual magnetic poles on the surface of the globe can range from kilometers per year (at the average values of the declination and inclination) to tens, hundreds and even thousands of kilometers per hour (minute and second values of the declination and inclination). There is no doubt that the speed and scale of "walks" the true magnetic North pole have to deal during conducting absolute geomagnetic measurements in the area of it's search.
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GLOBAL DISTRIBUTION OF ENERGETIC PROTON PRECIPITATION EQUATORWARD OF THE ISOTROPY
BOUNDARY
Semenova N.V., Popova T.A., Yahnina T.A., Yahnin A.G.
Polar Geophysical Institute, Apatity, Russia
On the basis of NOAA POES observations we constructed a map of the global occurrence rate of energetic proton precipitation (EPP) equatorward from the isotropy boundary. One of the observed features is a separate EPP population on the dayside. This precipitation is observed within 10-17 MLT, and consists of wide (>2° in latitude) enhancements, which differ from the localized (≤1° in latitude) precipitation pattern in other MLTs. In contrast to localized EPP events, which tend to concentrate around L=4-6, the events on the dayside are spread at L>6. The occurrence rate of the dayside EEP increases with an increase of the solar wind dynamic pressure. We compared the global distribution of EEP with observational statistics of EMIC waves revealed from magnetospheric spacecraft data, and found the remarkable similarity. To confirm the relationship between EPP and EMIC waves we considered simultaneous observations onboard THEMIS spacecraft and NOAA POES. The consideration of conjugated events demonstrates that EPP at low altitudes has an EMIC wave counterpart in the equatorial plane. Also, we found the coincidence of EEP with observations of geomagnetic pulsations Pc1, which are known as a ground signature of EMIC waves. Thus, both the statistical and case studies confirm that EPP events are the result of the ion-cyclotron instability in the equatorial magnetosphere.
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FORECASTING CONDITIONS OF THE EARTH'S OUTER RADIATION BELT ACCORDING TO SPACE
EXPERIMENTS
Sentemova N.S., Myagkova I.N., Dolenko S.A., Shirokyj V.R.
SINP MSU
Earth's magnetosphere is a space surroinding Earth, in which charged particles are controlled by the Earth's magnetic field, which is close to dipolar. Earth's radiation belts are inner regions of the Earth's magnetosphere, in which charged particles, such as electrons, protons and alfa-particles are held. Magnetosphere's condition changes due to high-energy fluxes of the Solar wind and coronal mass ejections. Outer radiation belt is caracterised by extreme instability. Abrupt increase of the high-energy electron fluxes may cause breakdown in microcircuts onboard the spacecrafts. This results in extreem necessity of broadcasting electron fluxes in the outer radiation belt. The task of broadcasting the fluxes was solved with the neural network — perceptrons, trained with the backpropagation method. Neural network was chosen as an adaptive algorithm, effective in cases where deterministic model doesn't yet exist. Neural modeling of the fluxes was build with the delay of the time seriese of folowing parameters: density and velocity of the Solar wind, geomagnetic indexes Dst and Kp, module |B| and components Bx, By, Bz of intencity of the magnetic field measured in the first libration point of the GSM system and values of electron fluxes in the outer radiation belt, received in the cosmic experiment with the satellite GOES, placed in the geostationary orbit. Also, values of sine and cosine of the time with the period of 24 hours and one year were added to the set of inputs to train the neural networks with the information about periodic time changes. Forecast was created for the horizons from 1 to 12 hours presented in the work. Also a different approach were attempted to forcast the average value of fluxes for a one, two and three days. To estimate and compare the quality of the forecast for diffent models were used following indicators:
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coefficient of determination, coefficient of correlation, mean sqare standart error. Quality of the forecast of electron fluxes decreases smoothly and slowly with the increase of the horizon. Therefore, there's a possibility to increase the horizon of the forecast. It confirms the preposition that distinctive time of development of the processes in the Earth's magnetosphere, which influences the fluxes in the outer radiation belt, is larger then distinctive time of development of the geomagnetic disturbanses. There were attempts to forecast other parameters of the GSM system. No abrupt decrease of the forecast were noted in any model, which means that time of the development processes in the Earth's magnetosphere is significantly larger then time of flow from the libration point to the Earth.
EFFECT OF IMF TURBULENCE IN THE VICINITY OF INTERPLANETARY SHOCKS ON GEOMAGNETIC
STORMS AND SUBSTORMS GENERATION
Shadrina L.P.1, Starodubtsev S.A.2
1 - Academy of Sciences of Republic of Sakha (Yakutia) 2 - Yu. G. Shafer Institute of Cosmophysical Research and
Aeronomy SB RAS
A statistical analysis of interplanetary shocks and ICMEs and their effects in the geomagnetic field – registration of SSCs, degreases of Dst and increases of AE indices – was fulfilled. Based on the comparison of shock and ICME lists from the WIND and ACE satellites in-situ observations together with ground-based indices of the geomagnetic field we evaluated the geoeffectiveness of interplanetary shocks in the 23rd solar cycle (1997-2008 years). It was shown that the interplanetary shocks form three roughly equal-size groups: 1 – the shocks with ICMEs, which generate at Earth more part of intense geomagnetic storms and substorms (27% of events); 2 – the shocks without ICMEs, which are usually produce at Earth weak and moderate geomagnetic storms and short-time substorms (42%); 3 – the shocks, which appear at Earth only as SC or does not have geoeffects (31%). The presence of the turbulent region ahead of the shock front
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increases the shock geoeffectiveness.
PHASE SHIFT BETWEEN SOLAR HEMISPHERES IN THE ACTIVITY CYCLE
Shibalova A.S.1, Obridko V.N.2, Sokoloff D.D.1,2
1 - Lomonosov MSU 2 - IZMIRAN
The research is devoted to the shift of activity cycles in the northern and southern solar hemispheres and is based on the information about the quantity and total square of the sunspots. The Royal Greenwich Observatory (RGO) observations were used (solarscience.msfc.nasa.gov/greenwch.shtml). The obtained results were compared with the archival data records about episodes of a considerable asymmetry of solar cycles. A marginal phase shift is observed between contemporary solar cycles in the northern and southern hemispheres. This shift distinguishes from the episodes of a high deviations from the dipole symmetric distribution of the sunspots, which is registered with the different reliability in the archival astronomical records during XVII ― XIX centuries. At present the time shift between solar hemispheres is about 6 ─ 7 months. In the immediate past of solar activity the shift changed its sign twice, that corresponds evidently to its non-strict periodic changes with the character time close to the duration of the Glaysberg cycle.
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MODEL OF SUBPROTON-SCALE MAGNETIC HOLES
Shustov P.I.1,2, Artemyev A.V.1,3, Vasko I.Y1, Yushkov E.V.1,2
1 - Space Research Institute, RAS, Profsouznaya st., 84/32, GSP-7, 117997 Moscow, Russia
2 - Department of Physics, Moscow State University, 119992 Moscow, Russia
3 - Department of Earth, Planetary, and Space Sciences and Institute of Geophysics and Planetary Physics, University of
California, Los Angeles, 90095, CA, USA
Magnetic holes are local structure with depressions in magnetic field strength |B|. They are commonly observed in the solar wind and in the Earth’s magnetosphere. Spacecraft observations suggest that magnetic holes represent stale structures where magnetic field variation is supported by strong electron currents maximizing around hole boundaries. We provide a model (kinetic) description of observed features of the magnetic holes. We solve Vlasov equation with distributions functions of electrons and ions. These distributions provide a current density for Maxwell’s equation for both planar and cylindrical hole configuration. Obtained profiles of magnetic and electric fields, electron and ion currents, can describe observe features of the magnetic holes.
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THE ANALYTICAL DESCRIPTION OF THE EARTH’S RING CURRENT PROTON FLUX FOR THE 90° PITCH
ANGLE
Smolin S.V.
Siberian Federal University, Department of Theoretical Physics, Krasnoyarsk, Russia
As mathematical model is offered the ordinary differential equation for the analytical description of a perpendicular differential flux of the charged particles in the Earth’s magnetosphere which depends on time and several parameters. The equation is fair under the certain geophysical conditions and on a time interval approximately no more than three hours. Comparison of results on the offered model and on full model for the pitch angle range from 0 up to 180 degrees is lead. For a perpendicular differential flux of the Earth’s ring current protons very good consent with the maximal relative error approximately some percent is received.
THREE-DIMENSIONAL MODEL OF THE EVOLUTION OF THE EARTH'S RING CURRENT
PROTONS DURING THE MAGNETIC STORM
Smolin S.V.
Siberian Federal University, Department of Theoretical Physics, Krasnoyarsk, Russia
The non-stationary three-dimensional mathematical model describing evolution of proton distribution function is offered. The distribution of the ring current protons in the inner magnetosphere during the magnetic storm is studied. The temporal and spatial evolution of the proton phase space densities in a dipole field is calculated using a three-dimensional model,
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considering radial, pitch angle and energy diffusions. The loss terms are described due to charge exchange and wave-particle interactions. The simulation starts with a quiet time distribution. The model is tested by comparing calculated proton fluxes with Polar/MICS measurement during the magnetic storm on 21 -- 22 October 1999. The good consent of the model pitch angle distributions of protons with the experimental data is received.
SPECIALIZED AUROMAG DATABASE OF HISTORICAL GEOMAGNETIC AND AURORAL
ACTIVITY
Soldatov V.A., Sokolov S.N., Ptitsyna N.G., Tyasto M.I.
SPbFIZMIRAN, St. Petersburg, Russia
The AuroMag database (http://db.izmiran.nw.ru/auromag) has been designed for providing web access to the Russian historical collection of geomagnetic and aurora borealis data. It is targeted specifically for research in the various aspects of space weather and space climate. The database consists of ≈15 000 high quality scanned digital images of original magnetograms produced primarily with the archival purpose, and this work ongoing. The database includes data for geomagnetic storms according to catalogues of Pavlovsk/Slutsk (1878-1941), Voejkovo (1947-1954) as well as data on the aurora borealis registered by 141 Russian meteorological stations (1837-1909). Additionally catalogues of geomagnetic storms from Greenwich, Abinger (1840-1954), and Colaba (1872-1905) stations are included. Compatibility of used standards of time and units were verified, typos and errors were fixed. User is given easy access to individual magnetograms at various zoom levels, with the ability to browse and search the entire database by several parameters: date, place, intensity, nature of the event, etc.
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UPFLOW IONOSPHERIC PLASMA IN THE POLARIZATION JET REGION
Stepanov A.E.1, Khalipov V.L.2, Kotova G.A.2, Kobyakova S.E.3, Bogdanov V.V.4, Kaisin А.V.4
1 - Institute of Cosmophysical Research and Aeronomy of SB RAS
2 - Space Research Institute, RAS 3 - Institute of Cosmophysical Research and Aeronomy SB RAS
4 - Institute of Cosmophysical Research and Radiowave Propagation, FEB RAS
According to Doppler measurements at sub-auroral ionospheric station Yakutsk the vertical and horizontal plasma drifts during the polarization jet (PJ) event are investigated. It is shown that during the PJ observation the vertical and horizontal drifts significantly higher than the background level. On the polar edge of the main ionospheric trough is changed the direction of the ionospheric plasma flow from ascending to descending. Doppler measurements of the DPS-4 ionosonde were compared with synchronous measurements of the plasma drift on the DMSP satellites during their pass near the Yakutsk meridian. Two kinds of measurements are in good agreement with each other. In the course of the world magnetic storm of 23.06.2005 the ascending velocities of the plasma flow by measuring the DMSP satellites were 1 - 1.4 km/s at a height of 850 km. At the ionospheric heights it is correspond to 150 m/s. Westward drift of the plasma by satellite measurements reached up to 2.5 km/s. Development of polarization jet in the ionosphere accompanied by a decrease in electron density of 10 times for 15-30 minutes.
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SOLAR ACTIVITY AND VARIATIONS IN RADIO FREQUENCY PULSE NUMBER OF LIGHTNING
DISCHARGES RECORDED IN YAKUTSK IN SUMMER 2001-2015
Tarabukina L.D.1,2, Kozlov V.I.1,2, Korsakov A.A.1
1 - Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of SB RAS
2 - M.K. Ammosov North-Eastern Federal University
The very low frequency pulses (VLF 0.3-30 kHz) have been recorded by the means of: coil antenna installed at the distance of 30 km from Yakutsk (62 N, 129.7 E) and oriented in west-east direction, 0.3-10 kHz preamplifier, pulse counter with 3 threshold levels – 1 V, 2 V, 3 V, analog-to-digit converter E440 and laptop computer. The threshold level was chosen to mean pulse rate being faster than 1s-1 in maximum in summer. The minimum-recorded electric filed was 1.75 mV/m, which is higher than the maximum of fluctuation component in considered region (1 mV/m). The data on lightning discharge number that is a main natural source of VLF pulses, was obtained by the World wide lightning location network (WWLLN). There are three typical periods in daily variations in pulse number due to local lightning activity and day-night propagation conditions: 3-7 UT, 8-9 UT and 15-19 UT. The averaged seasonal variations in pulse number divided by these three periods showed certain increase in 2001-2007 and decrease in 2008-2015 almost simultaneously with f10.7 index of solar activity. The ratio of pulse number between maximum and minimum was 13 times for 3-7 UT, 8 for 8-12 UT and 5 for 15-19 UT. Such variations could be explained by changes in propagation conditions, intensity of lightning activity or lightning activity spatial-temporal distribution. By measuring amplitude of two radio stations signals located in Khabarovsk and Novosibirsk near to high lightning activity regions in 2009-2013, we have estimated that the propagation condition variations due to solar activity contribute (1.25 times) less than observed changes in pulse number (3 times). Then we have considered the lightning activity variations in
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North Asia region. There is quasi-biennial redistribution in lightning discharge number between two areas of high lightning activity situated on the West Siberian Plain and in the Amur and Sungari rivers valley. The second area showed lightning activity with some negative feedback with solar activity in 2009-2015. Also, local lightning activity that produces relatively for our station large pulses shows negative feedback with solar activity in 2009-2015. We conclude that variations in radio pulse number in 2001-2015 is related with lightning activity and show strong negative correlation with solar activity.
PHYSICAL NATURE OF THE THERMO-ANOMALOUS LAYER DIAGNOSED BY THE EISCAT
RADAR WITHIN THE DUSTED NIGHTSIDE AURORAL LOW IONOSPHERE
Timofeev E.E.1, Shalimov S.L.2, Vallinkoski M.K.3
1 - Admiral Makarov State University of Maritime and Inland Shipping, the Saint-Petersburg, Russia
2 - Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
3 - Space Physics Department of the University of Oulu, Oulu, Finland
In the present study we analyze parameters of the lower ionosphere, measured by the EISCAT radar facility at the zenith of Tromsø auroral observatory during the ERRRIS campaign. Data used consists of 17 different nights of observations and includes 1900 simultaneous measurements of the electron (Te) and ion (Ti) temperatures, electron density (Ne) and vector of the ionospheric electric field (E-field). At that 75% and 25% of the data corresponds to measured E-field that is below and above the threshold of the Farley-Buneman instability, respectively. In the first part of our analysis the height profiles of the electron and ion temperature difference (Te-Ti) (including standard deviation, STD) for both, small and large electric fields were calculated using the superimposed epoch method. It was shown that:
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1) for the large electric fields (IEI>~20mV/m) the profile (Te-Ti) with Te>Ti takes the maximum (~ 70 К) at ~115 km in agreement with the standard conception; 2) for the small electric fields (IEI<~20mV/m) the thermal anomaly (TA)=(Ti-Te) was revealed when Te<Ti with maximum of the averaged TA value ~60 K at altitudes~106 km; 3) the thermal anomaly depends on the electric field value: among four intervals 0-5, 5-10, 10-15 and 15-20 mV/m the maximum of the anomaly is attributed to the third one, that is just below the normal threshold of the Farley-Buneman instability; 4) A permanent anti-correlation of the numerical derivatives of ion’s (dTi) and electron’s (dTe) temperatures was found during the thermal anomaly. The anti-correlation coefficient increases in phase with ionospheric E-field, averaged in the range of the correlation window, and reaches maximum of about ( - 0.9) near the FB-instability threshold (15-20 mV/m) decreasing quickly to zero with further E-field increase; 5) diurnal variation of the thermal anomaly turns out to be modulated by the atmospheric tides; 6) the STD of Ti and Te was found to be also significant (30-40 K) at the small electric fields. Interpretation of the thermal anomaly is based on the non-ideal plasma theory (Fortov et al., 2010) and experiments in laboratory dusty plasma (Olevanov et al., 2004), in which the temperature difference of about 60 K was observed under conditions similar to that in the ionospheric dusty dynamo layer (as it follows from the rocket measurements). For our case study, according to the measurement (the IMO site://www.imo.net/data/visual) there were considerable meteor activity during 1988 (with total number of meteors about ~1.5*105), so that one may await a noticeable dust level within the ionosphere. It follows from the laboratory experiment that in the presence of a negatively charged dust macro-particles the electron temperature can decrease whilst the ion temperature increases.
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THE MAGNETOSPHERIC “IDENTIKIT”: WHAT WE KNEW AND LEARNED OVER FOUR SOLAR CYCLES
WORTH OF SPACECRAFT MEASUREMENTS?
Tsyganenko N.A.
Saint-Petersburg State University, Saint-Petersburg, Russia
Unlike the meteorological conditions in the terrestrial atmosphere, the space weather and the environment it impacts cannot be directly seen and felt. Its monitoring and forecasting can presently be done only on the basis of satellite data, scattered in time and space, as well as by means of the computer simulations. In general, reconstructing the magnetospheric configurations and their dynamics from data can be likened to generating a person’s picture using incomplete descriptions collected by witnesses at different times, i.e., to constructing a composite portrait, or “identikit”. In the case of the magnetosphere, the problem is much more complicated due to the object’s variability and owing to a wide range of the external input scenarios. In this case one has to reconstruct not just one static configuration, but a dynamical “portrait gallery”, based on current conditions in the solar wind and their previous history during preceding hours, if not days. Before the space era, the empirical modeling of the geomagnetic field was limited to its main part and employed only ground-based measurements. With the launch of the first spacecraft, rapid outward expansion of the exploration started about four solar cycles ago, and the principal method adopted in the construction of the models was to synthesize measurements and indirect theoretical information on the magnetic field structure. The huge amount of archived data collected since then, as well as its continuing growth, already ensure a sufficient coverage both in the geometric and parametric space, which opens a possibility to revise the traditional approach to the empirical modeling. The goal of the revision is to reduce and, in perspective, to completely lift a priori restrictions on the mathematical structure of the models, to increase their flexibility, resolution and, as a result, to maximize the amount of information derived from the measurements. In the present review, modern methods of constructing and parameterizing the empirical models will be
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briefly described, as well as the most recent works in that direction by the author and his co-workers.
THE STRATOSPHERIC POLAR VORTEX AS A CONTROLLING FACTOR OF COSMIC RAY
INFLUENCE ON CYCLONIC PROCESSES AND LOW CLOUD ANOMALIES AT MIDDLE LATITUDES
Veretenenko S.V.1,2, Ogurtsov M.G.1,3
1 - Ioffe Physical-Technical Institute, St.Petersburg, Russia 2 - St.Petersburg State University, St.Petersburg, Russia
3 - Main Astronomical Observatory, St.Petersburg, Russia
In this work we continue studying the nature of links between low cloud anomalies (LCA) and galactic cosmic ray (GCR) variations on the decadal time scale, the ISCCP cloud data being used, as well as we consider possible reasons for the violation of positive correlation LCA-GCR in the early 2000s. It was shown that correlation links between cloud cover at middle latitudes and GCR intensity are due to GCR influence on the development of extratropical baric systems (cyclones, troughs) which form cloud fields. Positive correlation between low cloud anomalies and GCR variations detected in the period 1983-2000 results from the intensification of cyclonic activity at middle latitudes associated with GCR increase in the 11-yr solar cycle, these effects being similar in the Northern and Southern hemispheres. In the period of most significant correlations of cyclonic activity and low cloud anomalies with GCR intensity the stratospheric polar vortices in both hemispheres were strong, especially in the Northern one. Violation of positive correlation LCA-GCR occurred in the early 2000s almost simultaneously in the Northern and Southern hemispheres and coincided with a sharp weakening of both polar vortices. The changes of the vortex states seem to cause the reversal of GCR influence on the development of extratropical baric systems and, therefore, on cloud cover variations. The results obtained provide evidence for an important part of the stratospheric polar vortices in solar-atmospheric links. The vortex evolution seems to be a reason for temporal variability of solar activity
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effects on the lower atmosphere characteristics.
KINETIC MODELS OF MAGNETIC FLUX ROPES OBSERVED IN THE EARTH MAGNETOSPHERE
Vinogradov A.A.1, Vasko I.Y.2, Artemyev A.V.2,3, Yushkov E.V.1,2, Petrukovich A.A.2, Zelenyi L.M.2
1 - Department of Physics, Lomonosov Moscow State University, Moscow, Russia
2 - Space Research Institute of Russian Academy of Sciences, Moscow, Russia
3 - University of California, Los Angeles, California 90095, USA
Magnetic flux ropes (MFR) are universal magnetoplasma structures (similar to cylindrical screw pinches) formed in reconnecting current sheets. In particular, MFR with scales from about the ion inertial length to MHD range are widely observed in the Earth magnetosphere. Typical MFR have force-free configuration with the axial magnetic field peaking on the MFR axis, whereas bifurcated MFR with an off-axis peak of the axial magnetic field are observed as well. In the present work, we develop kinetic models of force-free and bifurcated MFR and determine consistent ion and electron distribution functions. The magnetic field configuration of the force-free MFR represents well-known Gold-Hoyle MFR (uniformly twisted MFR). We show that bifurcated MFR are characterized by the presence of cold and hot current-carrying electrons. The developed models are capable to describe MFR observed in the Earth magnetotail as well as MFR recently observed by Magnetospheric Multiscale Mission at the Earth magnetopause.
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FORMATION OF THE TWO-DIMENSIONAL ELECTRIC FIELD STRUCTURES IN THE AURORAL
CAVITY
Volkov M.A.
Murmansk State Technical University
The propagation of the "inertia" waves in the auroral cavities was studied. The equations description of the waves propagation were determined. From the analysis of these equations the longitudinal and transverse (along and across magnetic field of the Earth) scales wave structures were otained. The scale across the magnetic field in the ionosphere is ~ 1 km.
CHARACTERISTICS AND CONDITIONS FOR GENERATION OF ISOLATED SUBSTORMS
Yagodkina O.I., Vorobjev V.G., Zverev V.L.
Polar Geophysical Institute, Apatity, Murmansk region
The characteristics of isolated substorms which were selected from 1-min AL-index variations are examined. For the winter seasons 1995-2012 it was selected 112 substorms, which answered the established for selection criteria. All substorms were divided into several types depending on the IMF Bz component behavior during the substorm onset. We found that only about 19% of substorms studied were associated with northward turnings of IMF, while ~53% of substorms were occurred during southward IMF. It was discovered significant number of events, when after prolonged (>30 min) interval of southern IMF and subsequent sharp northward turning of the IMF Bz component no substorm activity was observed in the auroral zone. These results indicate that the northward turning of the IMF is neither a necessary nor a sufficient condition for the generation of substorms. It is shown that the average duration of the southern IMF before onset and
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average intensity of magnetic perturbations in the maximum of substorm were approximately the same for both types of substorms and were about 80 min and 650 nT, respectively. However, the average substorm duration, including growth and recovery phases, is longer in average on about 30 min for the substorms during Bz < 0 than the duration of substorms associated with the northward turning of Bz. Correlations between loading and unloading processes of the magnetosphere were examined by using different solar wind-magnetosphere coupling functions. It is shown that the best correlation (r = 0.84) occurred with the function dΦ/dt = V4/3·BT
2/3·sin8/3 (Ө/2) proposed by Newell et al., [2007]. A high correlation (r = 0.75) is marked when the simple function V*BS was used.
ON THE ROLE OF EMIC WAVES IN PRODUCTION OF RELATIVISTIC ELECTRON PRECIPITATION
Yahnin A.G.1, Yahnina T.A.1, Raita T.2, Manninen J.2
1 - Polar Geophysical Institute, Apatity, Russia 2 - Sodankyla Geophysical Observatory, Sodankyla, Finland
The interaction with EMIC waves is often considered as one of the most important mechanisms for scattering radiation belt relativistic electrons into the loss cone. At the same time other mechanisms (e.g., interaction with hiss and UHR waves as well as scattering due to violation of adiabatic motion of particles in a weak magnetic field) сan also be responsible for relativistic electron precipitation (REP). The relative role of different precipitation mechanisms is not clear. To investigate the role of EMIC waves, the database consisting of 1060 REP events (so called “precipitation bands”) observed by several NOAA POES spacecraft between 1 July and 31 December 2005 was used. From this amount, 81 events were observed within the ± 1 hour MLT range around the Finnish network of search coil magnetometers operated by Sodankyla Geophysical Observatory. The combined satellite and magnetometer data revealed 15 REP events (18.5%) associated with geomagnetic pulsations in the Pc1 range. These Pc1 associated REP events coincide with simultaneous observations onboard POES of localized precipitation of energetic (E=30-80 keV) protons (LPEP). Both Pc1 and LPEP are known as, respectively, ground and space-
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borne counterparts of the EMIC waves. Observations of LPEP were used to select the EMIC wave driven REP events from the whole database. Only 155 of 1060 REP events (~15%) related to interaction with EMIC waves were found. Thus, the majority of relativistic electron precipitation is produced by other mechanisms, not by interaction with EMIC waves.
COLD PLASMA DENSITY IN THE REGIONS OF THE REP GENERATION
Yahnina T.A., Yahnin A.G.
Polar Geophysical Institute, Apatity, Russia
Observations of relativistic (~1 МэВ) electron precipitation (REP) with the NOAA POES revealed two types of events, which are suggested to be related to wave-particle interaction. The first one is related to the energetic (>30 keV) electron precipitation and second one – to precipitation of energetic protons. Using cold plasma measurements onboard geosynchronous LANL spacecraft we tried to estimate the cold plasma density in the regions of the REP generation. We mapped REP onto the equatorial plane of the magnetosphere, and selected those events, which were originated close to the geostationary orbit. The density has been determined on the basis of measurements of two LANL spacecraft, one of which crossed the generation region before and another after the REP registration moment. Interpolation between these two values provides the estimation of the cold plasma density in the source region. We found ~70% of REP events related to energetic electrons were observed in connection with low-density (<10 cm-3) trough plasma, and some 30% of such events were within denser (10-60 cm-3) plasmaspheric plasma. Almost all REP events related to energetic protons were found in dense (15-40 cm-3) plasma. All dense plasma events were registered in the evening-night MLTs. We discuss how the obtained relation to cold plasma density may help for determination of the wave modes responsible for scattering relativistic electrons into the loss cone.
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ELECTRON ANISOTROPY AND THE DAWN-DUSK MAGNETIC FIELD IN THE EARTH MAGNETOTAIL
Yushkov E.V.1, Artemyev A.V.1, Petrukovich A.A.1, Nakamura R.2
1 - Space Research Institute, RAS, Moscow, Russia 2 - Space Research Institute (IWF), AAS, Graz, Austria
Using nine years of Cluster observations in the Earth magnetotail, we investigate electron temperature anisotropy and its dependencies on yB and zB magnetic field components (in GSM coordinates). We characterize anisotropic electron population by temperature ratio ⊥TT /|| and phase space density ratio ⊥FF /|| for along ( || ) and transverse (⊥ ) directions to background magnetic field. We show that electron anisotropic population identified by large ⊥FF /|| ratio can exist in plasma sheet with small
⊥TT /|| . We confirm that ⊥TT /|| anisotropy increases significantly with zB and : growth results in formation of strong peak near
the neutral plane , whereas growth results to increase for wide range. We obtain that anisotropic population is organized as a set of short (few seconds) bursts of strong electron anisotropic fluxes embedded within long time intervals of plasma sheet observations with increased and . We demonstrate that the dependencies of on and have clear dawn-dusk asymmetry: increase corresponds to growth at dusk flank, and at dawn flank for . Using differences of electron anisotropy dependencies on and components, we discuss possible mechanisms responsible for its formation.
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ANISOTROPY AND ION ACCELERATION IN RECONNECTION EXHAUST
Zaitsev I.V., Divin A.V., Semenov V.S.
Saint-Petersburg State University
In this study we present the results of numerical simulations of a tangential discontinuity decay be means of 1D Particle-in-Cell (PIC) method. The evolution of travelling shocks displays much similarities with the distant outflow region of magnetic reconnection. Numerical simulations allowed us to detect a variety of features not resolved by conventional MHD simulations of Riemann task: 1) Slow-mode-like shocks display complicated kinetic structure with beams, plasma anisotropies and waves; 2) Particles crossing the shock are picked-up by reconnection electric field and are accelerated up to Alfvén velocity; 3) Parameter study shows dependence of the compression ratio on the guide field; 4) Firehose instability is generated in the exhaust because of strong parallel anisotropy there
ELECTROMAGNETIC ULF WAVE ENERGY LEAKAGE THROUGH THE IONOSPHERE AS OBSERVED BY LOW-ORBITING SATELLITES
SWARM
Zelikson I.S., Pilipenko V.A.
Institute of the Earth Physics, Moscow, Russia
We study the transmission of ULF waves in the band Pc3/Pi2 through the ionosphere to the ground. For that the synchronous data from low-orbiting satellites SWARM and ground magnetometer arrays AMBER, CARISMA, and MAGDAS have been used. The analysis of combined satellite/ground
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observations gives a possibility to reveal a physical nature of Pc3 and Pi2 waves in the upper ionosphere.
ON THE SPECIFIC PROPERTIES OF DIURNAL VARIATION OF THE PC1 GEOMAGNETIC
PULSATION AT MIDDLE LATITUDE
Zotov O.D.
Borok Geophysical Observatory, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Borok, Yaroslavl oblast, Russia
This work is devoted to study of patterns of the diurnal variation of the Pc 1 geomagnetic pulsations at middle latitudes. The catalogs of mid-latitude observatories Borok (58 N - 39E, from 1958 to 1995) and Mondy (51N - 100E, from 1958 to 1980) have been analyzed statistically. We investigated the dependence of the form of Pc1 diurnal variation on the phase of the solar cycle. The Pc1 with periods T > 2 s and T < 2 s analyzed separately. When analyzing Pc1 without selection by periods, the diurnal variation Pc1 has maximum which position depends on the phase of the solar activity cycle. At the Borok observatory the maximum of daily variation during the maximum of solar cycle activity occurs earlier than during the minimum of solar cycle activity. At the Mondy observatory we see the opposite picture. It is shown that the maximum of diurnal variation depends on the period of Pc1. The observation of the diurnal variation maximum with the fixed period of Pc1 does not depend on the phase of the solar cycle. The probability of Pc1 occurrence is in antiphase with solar cycle activity. It does not depend on the period of Pc1. The distribution of Pc1 events on the period has the exponential form, and the exponent does not depend on the phase of solar cycle. The distribution of Pc1 events on the amplitudes has the exponential form, and the exponent depend on the phase of solar cycle. The Pc1 waves with the large amplitudes (> 100 pT) are practically absent during the periods of high solar activity. The problem of impact of IMF on the Pc1 wave activity is discussed shortly. This work was partially supported by RFFI grants no.15-05-00491 and no.16-05-00056.
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P. PALEOMAGNETISM AND ROCK MAGNETISM
PRELIMINARY DATA ON THE MAGNETIC PROPERTIES OF LAKE RUBSKOE SEDIMENTS
(IVANOVO REGION)
Akhmerov R.D., Nurgaliev D.K., Kosareva L.R., Kuzina D.M., Krylov P.S., Antonenko V.V., Yusupova A.R.
Kazan Federal University, Russia
Paleoclimate currently represents an interesting area of scientific research associated with understanding processes and causes of climate change in the past, which makes it possible to accurately predict such changes in the future. There is a beautiful and clean lake Rubskoye in the heart of the midland of Russia. The water of the lake is containing large quantities of calcium, magnesium, bicarbonate. In the summer of 2015 the staff of the Kazan Federal University (KFU) was carried out expedition to the largest lake in Ivanovo region. Lake Rubskoye is located in 42 km to southwest of Ivanovo. The lake area is 303 ha. Maximum length 2980 m, width - 1550 m, depth - 17 m. Lake has glacial origin and it is mesotrophic. In this expedition previously conducted seismic profiling, which allows to identify the points of the core columns extraction. The core was obtained from drilling of precipitation of the lake using specialized hydraulic sampler, designed and manufactured by the staff of the paleomagnetic laboratory of the KFU. There were selected 5 columns. The developed system of preparation of a collection of samples for paleomagnetic and magnetic mineralogy investigations provides for stratified sampling of undeformed central part of the core of their sealed packaging in labeled plastic containers and transportation of collection in permalloy screens in the lab. There were selected more than 900 samples. Laboratory studies were carried out in the paleomagnetic laboratories of KFU and Resource center "Geomodel" (SPbSU, Russia). Investigations were include measurements of magnetic susceptibility, hysteresis parameters (coercive spectra of the
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magnetization and the demagnetization), the dependence of inductive magnetization on temperature. The work was carried out according to the Russian Government’s Program of Competitive Growth of Kazan Federal University and supported by the Russian Foundation for Basic research (14-05-00785 А).
NEW ARCHEOINTENSITY DATA FROM LATE NEOLITHIC HALAFIAN SETTLEMENT YARIM TEPE
2 (NORTHERN IRAQ): GEOMAGNETIC AND ARCHEOLOGICAL IMPLICATIONS
Akimova S.V.1,2, Gallet Y.1, Amirov S.N.3
1 - Institut de Physique du Globe de Paris, France 2 - Institute of Physics of the Earth RAS, Moscow, Russia
3 - Archeological Institute RAS, Moscow, Russia
The main goal of this study is to recover the geomagnetic field intensity variations in the Middle East during the 6th millennium BC, with a particular interest on rapid variations. We will report on new archeointensity data obtained from Yarim Tepe 2 (Northern Iraq), an ancient multilayered settlement dated from the Late Neolithic Halaf period (~5950 – 5300 BC). Unearthed by Soviet archeologists between 1969 – 1976, this site revealed a 7-m thick sequence of cultural deposits, divided into 9 archeological levels (building horizons). A very important collection of artifacts from Yarim Tepe 2, in particular several thousands of potsherds, is stored at the repository of Archeological Institute in Moscow, where our sampling was undertaken. We collected 29 groups of fragments from superimposed stratigraphic layers of about 20 cm thickness in average. Each group consists of at least 3 (up to 10) fragments. All data were carried out using the three-axis vibrating sample magnetometer Triaxe, which allows magnetization measurements of a small samples (< 1 cm3) directly at high temperatures. Archeointensity results were obtained using the experimental protocol developed for the Triaxe magnetometer. This protocol takes into account both the anisotropy and cooling rate effects on thermoremanent
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magnetization acquisition. Together with other data, previously obtained from Syria and Bulgaria the new archeointensity results show the occurrence of a short-lasting geomagnetic field intensity peak around ~5500 BC, with intensity variation rates as high as ~ 0.35 – 0.15 µT/year over a few decades. We will also present X-ray data obtained on a set of potsherds from Yarim Tepe 2, which provide interesting new constraints on the heating temperatures reached during the production of the ceramics. The reported study was funded by RFBR, research project No. 16-35-00555 mol_a, and grant of Russian Ministry of Research and Education No. 14.Z50.31.0017.
MODELING OF THE EXCHANGE BIAS OF THE HYSTERESIS LOOPS IN LOW-TEMPERATURE
MAGNETITE
Anisimov S.V., Afremov L.L., Iliushin I.G.
Far Eastern Federal University
Such magnetic characteristics as coercive field and magnetization are well studied, but the origin of the exchange bias of the hysteresis loops observed in the low-temperature state of magnetite is still a question and don’t have sufficient theoretical explanation. In reference [1] Senn et al. have investigated crystal structure of magnetite below Verwey temperature. He showed, that structure unit named “trimeron” can be distinguished in the B-sublattice of magnetite. This structure consists of 3 iron ions – 2 of them are Fe3+ and one is Fe2+. Central Fe2+ ion is the donor of minority-spin electron of the trimeron. Interaction between ions and minority-spin electron leads to distortions in crystal structure that has been reported earlier [2]. It is well known, that exchange bias is not observed in the pure magnetite. However, it can be observed in the case of heterophase structure, when two crystal lattices are borders with one another (i.e. magnetite and iron lattices) [3]. We associate this phenomenon with the interaction between atoms of additional crystal lattice covering magnetite and atoms of the trimerons closest to the surface of the magnetite crystal lattice. In this work we simulate spin-orbital interaction of the surface trimeron of
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the magnetite with the iron lattice covering it. [1] Mark S. Senn, Jon P. Wright & J. Paul Attfield, Charge order and
three-site distortions in the Verwey structure of magnetite. Nature, 2012, 481, 173-176;
[2] Iizumi M., Koetzle T. F., Shirane G., Chicazumi S., Matsui M. and Todo S., Structure of Magnetite (Fe3O4) below the Verwey Transition Temperature. Acta Cryst. 1982, B38, 2121-2133;
[3] Xiaolian Sun, Natalie Frey Huls, Aruna Sigdel, and Shouheng Sun, Tuning Exchange Bias in Core/Shell FeO/Fe3O4 Nanoparticles. Nano Lett. 2012, 12, 246−251.
ON THE ORIGIN OF L-SHAPED ARAI-NAGATA DIAGRAMS
Aphinogenova N.A., Shcherbakov V.P., Tsel'movich V.A., Smirnov M.A., Kozmina L.V.
BGO IPE RAS
When performing the Thellier experiments, a sharp drop in NRM at T < 300-500 °C accompanying by a very weak acquisitions of complementary pTRM is sometimes observed on the Arai-Nagata diagrams. On contrary, at higher temperatures this drop transforms into a very sharp increase in the induced PTRMs with virtually stopped decrease of NRM (L-shaped diagrams ). In some cases the sharp drop in NRM at lower T is absent while the phenomenon of the sharp increase in high-temperature pTRMs still remains. A study of 6 samples from the collections of the Kola and the Crimea Peninsulas revealing prominent features of such the behavior of the Arai-Nagata diagrams clearly link this phenomenon to the inversion of single-phase oxidized grains of magnetite to hematite. If before the Thellier experiments these samples were exposed to an alternating field with the amplitude 5-10 mT, the value of NRM falls several times and a sharp drop of NRM on the Arai-Nagata diagrams disappeared. This means that the major part of NRM in the initial state is in a metastable state. The formation of high-temperature pTRMs at T > 450-500 °C is caused by the high-temperature (heterophase) oxidation of TM grains.
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ON THE POSSIBLE SELF-REVERSAL OF MAGNETIZATION OF TITANOMAGNETITE
Belokon V.I.1, Dyachenko O.I.2
1 - Far Eastern Federal University, School of Natural Sciences, Theoretical and nuclear physics department
2 - Far Eastern Federal University, School of Natural Sciences, General and experimental physics department
In the framework of the molecular field theory we discuss the conditions for the emergence of self-reversal of magnetization of titanomagnetite. Effects of self-reversal of magnetization repeatedly studied in several publications [1, 2]. The Ti ions substitute Fe3+ at B-sublattice, causing transitions Fe3+ into Fe2+. Thus, the neutrality of the titanomagnetite molecule is saved. It is believed, that such transitions are typical for ions at A-sublattice. As the Ti concentration x equal to one, the antiferromagnetic ordering takes place and the Curie temperature of the phase transition determined as Tc = -1500C. Then, as will be shown below, the self-reversal of magnetization at the N-type Neel is impossible. If the conditions are non-equilibrium, then we propose that the transition Fe3+ into Fe2+ occurs both at A- and B-sublattices. At x ≠ 0, we will have four subsystems (two systems are described A-sublattice and two systems are described B-sublattice) with the corresponding filling densities: 1. A- sublattice: the fraction of Fe2+ is α x (0 <α <1); 2. A – sublattice: the fraction of Fe3+ is equal to 1-α x; 3. B – sublattice: the fraction of Fe2+ is equal to 1 + (1-α x); 4. B - sublattice: the fraction of Fe3+ is (1-x) - (1-α) x, the fraction of Ti4 + is equal to x. The system of equations for the relative magnetic moment of each sublattices allow us to determine the exchange integrals J14 = J23, J13, J24 from the experimental data of the Curie points for x = 0, x = 0,5, x = 1 at α = 0, α = 0,5, α = 1 and calculate the total magnetic moment. It was found that self-reversal of the magnetic moment of the system can be observed at α = 0 in the range of 0,5 <x <0,65. In case of x > 0,65 there is a partial self-reversal of magnetization of titanomagnetite
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References 1. Ozima M, Larson E. E. J. Geomag. Geoelectr. 20 337 (1968) 2. Trukhin V.I., Bezaeva N.S. UFN 176 (5) 507 (2006)
HOW TO DISCRIMINATE BETWEEN THERMAL AND MECHANICAL EFFECTS OF SHOCK ON THE ROCK
MAGNETIC PROPERTIES OF BASALT AND DIABASE SPHERICALLY SHOCKED UP TO ~10-160 GPA
Bezaeva N.S.1,2,3, Swanson-Hysell N.L.4, Tikoo S.M.4,5, Kars M.6, Egli R.7, Badyukov D.D.8, Chareev D.A.9,2,3,
Fairchild L.M.4
1 - Faculty of Physics, M.V. Lomonosov Moscow State University, Moscow, Russia
2 - Institute of Physics and Technology, Ural Federal University, Ekaterinburg, Russia
3 - Institute of Geology and Petroleum Technologies, Kazan Federal University, Kazan, Russia
4 - Department of Earth and Planetary Science, University of California, Berkeley, USA
5 - Department of Earth and Planetary Sciences, Rutgers University, Piscataway Township, USA
6 - Center for Advanced Marine Core Research, Kochi University, Nankoku, Japan
7 - Central Institute for Meteorology and Geodynamics, Vienna, Austria
8 - Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, Moscow, Russia
9 - Institute of Experimental Mineralogy, Russian Academy of Sciences, Chernogolovka, Russia
Understanding how shock waves generated during hypervelocity impacts affect rock magnetic properties is key for interpreting the paleomagnetic
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records of lunar rocks, meteorites, and cratered planetary surfaces. Laboratory simulations of impacts show that ultra-high shocks may induce substantial post-shock heating of the target material. At high pressures (>10 GPa), shock heating occurs in tandem with mechanical effects, such as grain fracturing and creation of crystallographic defects and dislocations within magnetic grains. In many cases, this makes it difficult to conclude whether shock-induced changes in the rock magnetic properties of target materials are primarily associated with mechanical or thermal effects. Here we present novel experimental methods that may be used to discriminate between mechanical and thermal effects of shock on magnetic properties. We illustrate these methods with two examples of spherically shocked terrestrial basalt and diabase [1], which were shocked to pressures of ~10 to >160 GPa, and investigate possible explanations for the observed shock-induced magnetic hardening (i.e., increase in remanent coercivity Bcr). The methods consist of i) conducting extra heating experiments at temperatures resembling those experienced during high-pressure shock events on untreated equivalents of shocked rocks (with further comparison of Bcr of shocked and heated samples) and ii) quantitative comparison of high-resolution first-order reversal curve (FORC) diagrams (field step: 0.5-0.7 mT) for shocked, heated and untreated specimens. Using this approach, we demonstrated that the shock-induced coercivity hardening in our samples is predominantly due to solid-state, mechanical effects of shock rather than alteration associated with shock heating. Heating-induced changes in Bcr in the post-shock temperature range were minor. The FORC distributions of shocked samples maintained the same overall shape but was stretched towards higher coercivities, which is consistent with shock-induced hardening. While shock did not alter the intrinsic shape of the coercivity spectra and FORC contours, the heating experiment did as the result of mineralogical change. Reference: [1] Swanson-Hysell N. L. et al. 2014. G3 15:2039-2047.
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SOME PROBLEMS OF MAGNETIC AND PALEOMAGNETIC STUDY OF THE PLEISTOCENE
(THE CASE OF THE CHINESE LOESS PLATEAU SEDIMENTS)
Bol’shakov V.A.
M.V. Lomonosov Moscow State University
Pleistocene , the closest to the present geological period , covers the last 2.6 million years. Its distinguishing feature is the presence of significant global climate fluctuations - glaciations and interglacials . The study of this climate phenomenon is an urgent task of Earth Sciences. In particular, to solve this problem for sediment research of China Loess Plateau used paleomagnetic and magnetic methods . Loesses and separating them soils, usually formed respectively at the time of glaciations and interglacials contains one of the most comprehensive archives of paleoclimatic records of the Pleistocene fluctuations. The magnetic and paleomagnetic data are widely used to establish the chronology of records , as well as indirect paleoclimatic indicators. However , this use is facing a number of challenges that must be overcome in order to obtained on the basis of magnetic and paleomagnetic data conclusions can be considered correct . These problems are mainly the following . 1. Development of a " magnetic amplification "specific mechanism in the soils, with perhaps a more accurate determination of the impact of various environmental factors that cause qualitative changes in the magnetic fraction of soils (compared with loesses ) . 2. The exact definition of the climatostratigrafic positions of the main Pleistocene paleomagnetic benchmarks primarily the inversion Matyama -Brunhes.
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THE PROBLEM OF IDENTIFICATION OF HOLOCENE TEPHRA BY THERMOMAGNETIC METHOD
Burnatny S.S., Naumov A.N., Tsygankova V.I., Minyuk P.S.
NEISRI FEB RAS
The most important stratigraphic marker in the Holocene sediments of the North-East of Russia is tephra, correlated with tephra Kurile Lake caldera 7600 (14C) year BP (Ponomareva et al, 2004). Tephra is acid composition, white color and visually easily diagnosed in lacustrine and marsh sediments. Tephra is found in the Magadan Region and Eastern Yakutia and was studied from lake sediments and outcrops – Lake Chistoye. (59.543850 deg. N, 151.800185 deg. E), Lake Grand (60.730112 deg. N, 151.883534 ° E), Lake Chernoye (61.020365 deg. N, 151.739181 deg. E), Lake. Shchuch’ye (63.351465 deg. N, 140.990055 deg. E). Magnetic susceptibility (MS) in argon and air heating media were studied. Magnetite was determined on thermomagnetic curves. During heated in air, the oxidation of magnetite marked decline in magnetic susceptibility between 600 and 700 degrees. There is no oxidation in argon media. MS(T) warming curves show a gradual decrease in susceptibility and sharp drop close to 580 deg. in argon media. The cooling curves display a strong increase in susceptibility at 400 deg indicating the new formed mineral. This mineral is stable and visible on second run heating and cooling curves. During heating of same-aged tephra from outcrops, this mineral is not formed. It is assumed that the postsedimentation conditions of tephra is the main factor influencing the results of thermomagnetic data which complicates the identification of tephra on thermomagnetic curves.
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CURRENT MODEL OF THE MAIN GEOMAGNETIC FIELD: POSSIBILITIES AND RESTRICTIONS
Demina I.M., Gorshkova N.V., Farafonova Yu.G.
SPbF IZMIRAN
The paper studies the possibility of simulation of the spatial structure of the main geomagnetic field (MGF) using the system of the current loops (CL). Method of solving the problem is similar to simulation using dipole sources). Preliminary analysis of the properties of the inverse problem solution was carried out for the single CL. The CL parameters were calculated on the basis of the magnetic field components defined on the surface of a sphere with specified radius. It was obtained (found) that even in the ideal case, an isolated CL and random noise, estimates of all CL parameters except the current strength and radius of loop can be obtained. All estimates of these two parameters values line up close to the curve of permanent magnetic moment. At the same time the value of the latter was obtained with an error less than 1%. Reduction of the sphere radius to 4,000 kilometers improves results. The MGF approximation was carried out by IGRF12 coefficients for 2010 y. and only for non-dipole part. At the same time the inverse problem was solved for gufm-SAT-E3 and COV-OBS.x1 models, which, according to their authors, assume an extension to the core-mantle boundary. The comparison of the MGF spatial structure computed by different spherical models has shown that the marked differences concentrate in the polar regions. The IGRF and COV-OBS are the most similar in spatial structure. Many small-scale anomalies manifest in the difference between the COV-OBS and gufm-SAT-E3 when approaching the core-mantle boundary. It can be associated with higher order spherical polynomials. This leads to appearance of many large additive anomalies during MGF approximation even at the sphere radius 5500 km. Some of them are comparable to the anomalies created by currents whose parameters were determined by MGF on the Earth's surfers. In addition, the rapid growth of interpreted small-scale anomalies leads to deepening and displacement sources their approximating.
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MAGNETIC FIELD OF THE VOLUME CURRENT SYSTEMS ON THE EARTH'S SURFACE AND NEAR
THE CORE-MANTLE BOUNDARY
Demina I.M.1, Gorshkova N.V.1, Soldatov V.A.1,2
1 - SPbF IZMIRAN 2 - Library of the Russian Academy of Sciences
We performed the simulation of the volume current systems such as ring current, cone, cylinder, and spindle. The size, location and orientation in space varied for each body type. Components of the generated magnetic field were calculated at the Earth's surface and near the core-mantle boundary. We found that the magnetic field generated by such currents on the Earth's surface differs slightly from the field of the dipole even through the size of the volume current system is comparable to the radius of the liquid core. And the dipole as a source is the best approximation of this field with a minimum residual error. If the calculation sphere approaches the core-mantle boundary, the features related to the size of the source emerge. The dipole component of the main geomagnetic field is approximated the best by a noncentral sloping dipole or a current loop which radius is much smaller than the radius of the solid core. The simulation with a combination (the sum) of volumetric sources allows us to obtain a given spatial structure of Z component at the Earth's surface. As for the other components, we didn't carry out such a study because of its complexity. But, if the calculation sphere radius approaches the core-mantle boundary, the field of each source becomes distinguishable even in the case of Z component, i.e., the dipole component anomaly breaks up into individual anomalies in accordance with the number of given current systems.
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PALEOMAGNETISM OF THE SOUTHERN TIEN SHAN UPPER PALEOZOIC FORMAITIONS
Dvorova A.V.
Geological Institute RAS, Moscow
The views on the evolution of the Central Asian fold belt, including the South Tien Shan segment are extremely contradictory. This is largely due to the lack of paleomagnetic data on the Paleozoic of the Tien Shan. Some of the Permian volcano-sedimentary rocks were already studied in the eastern part of the Southern Tien Shan. Recently the collections of late Carboniferous-Early Permian red sandstones and siltstones (Formation Bagichi) from the southern slope of the Alai range, Permian rhyolites of the Hodzhakelenskoy Formation from the northern slope of the ridge Kichik-Alai and Late Permian red sandstones and siltstones of the Tuleykanskoy Formation from the Karachatyr mountains were re-studied. In most of the samples from the sandstones (31 sample from the Begich locality 39.6°N;71.9°E) a low-temperature component (LTC) was removed by heating to 200° to 350°C. LTC is indistinguishable from the present-day field direction for the area. After the removal of the LTC, a high-temperature component (HTC) was isolated at the temperature interval 540°-590°C(D°=188.4,I°=-56.0,k=25.9,a95°=9.2(n=12sample),after bedding correction). The average direction of this component is rotated by about 40º counterclockwise relative to the Permian reference data for the Baltic plate. Rhyolites were sampled at the northern slope of the ridge Kichi-Alai (40.1°N72.4°E,32samples). The HTC was isolated at the temperature interval up to 650°C (D°=152.1,I°=-54.3,k=40.1,a95°=6.1, n=16, after tilt correction). Red sandstones and siltstones were sampled at the Karachatyr mountains (40.4°N;72.5°E, 30 samples). The HTC was isolated at the temperature interval 650°-690°C (D°=148.3,I° = -45.7,k=30, a95°=6.4, n=19).The fold test is positive. The average direction of this component is rotated by about 80º counterclockwise relative to the Permian reference data for the Baltic plate. Large counterclockwise rotations identified in the East part of the Southern Tien Shan. Such rotations are known in adjacent territories [Bazhenov et al.,1999]. A single mecanics in formation of the structure of this segment of the Central Asian fold belt estimated.
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MAGNETIC PROPERTIES OF ROCKS COLLECTED FROM THE SEABED OF THE MENDELEEV RISE
(ARCTIC OCEAN): HIGH- AND LOW-TEMPERATURE BEHAVIOUR
Elkina D.V.1,2, Piskarev A.L.1,2
1 - Gramberg All-Russian State Research Institute for Geology and Mineral Resources of the World Ocean
"VNIIOkeangeologia" 2 - Saint Petersburg State University
It goes without saying that nowadays the Arctic Ocean is a region of rapidly rising both scientific and geopolitical interest. Despite the increasing number of studies on the area, some questions related to the nature and evolution of structural elements within the Arctic Basin remains fairly under discussion. From the other side, rock magnetic analyses of the seabed material carried out throughout the circumpolar region could shed the light on these issues from fundamental magnetic and mineralogical prospects. In 2012, the comprehensive geological and geophysical study, including seabed sampling using dredges, telegrabbers, and a subsea drilling machine was carried out at 10 sites across the Mendeleev Rise. Also large angular blocks were collected by a research submarine at the base of bedrock scarps (Morozov et al., 2013). Specimens obtained from this geological survey were subjected to a series of magnetic analyses from 2 K to 300 K, comprising saturation isothermal remanent magnetization (SIRM), cooling in a zero and a strong magnetic field (ZFC vs. FC) etc. Moreover, magnetic susceptibility temperature dependence has been obtained on the specimens in the interval of -200 - 700 °С (ca. from 73 to 973 K). All the measurements were performed at the Center for Geo-Environmental Research and Modeling (GEOMODEL) and the Center for Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics of the Research Park, St. Petersburg State University. Results have revealed not only comparable trends of titanium magnetite constituents for specimens from different sampling sites but also an abrupt absence of magnetite for several other ones not predicted by magnetic susceptibility
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temperature characteristics. Accordingly, the latter is supposed to represent titanomagnetite. Authors would like to express their gratitude to Andrey A. Kosterov for the assistance throughout the research. We also thank Sergey P. Shokalsky and Leonid R. Kolbantsev for their help during the work with the sample collection. References Morozov, A.F., Petrov, O.V., Shokalsky, S.P., Kashubin, S.N., Kremenetsky, A.A., Shkatov, M.Y., Kaminsky, V.D., Gusev, E.A., Grikurov, G.E., Rekant, P.V. and Shevchenko, S.S., 2012. New geological data are confirming continental origin of the central Arctic rises. Expedition, 2012(10).
PALEOMAGNETISM OF LATE PALEOZOIC AND MESOZOIC VOLCANIC ROCKS FROM SOUTH
TRANSBAIKALIA: NEW DATA
Fedyukin I.V.
The Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences
The main objects of the present study are late Permian and Mesozoic volcanic rocks from Selengin-Vitim volcano-plutonic belt (South Transbaikalia). The belt was formed in the back area of Siberian continent active margin. Volcanic rocks are presented by contrastive volcanites more than 5 km thick. The deposits are subdivided into three suits: Ungurkuy (basalts and andesites), Chernoyar (presented mostly by basalts, andesites and tuffs) and Hilok (mostly basalts, pyroclastic flows and tuffs). The age of Ungurkuy suite is deemed to be between Late Carboniferous and Late Permian. The age of Chernoyar suite is Middle-late Triassic. The age og Hilok suite is Late Jurassic. Volcanic deposits of the three suits were studied to create APWP for the Siberian craton. 250 oriented samples from 40 sites were collected from the Chikoy river valley within South Siberia. All samples were characterized by interpretable paleomagnetic signal. The Ungurkuy suite has different dip and strike: from subhorizontal to 40
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degrees inclination and NE course. Chernoyar rocks were collected from monoclinal structure with the dip and strike around NW declination and 5-10 degrees inclination. Hilok suite represents large subhorizontal eruptive bodies. Volcanic rocks of Ungurkuy suite show mostly monopolar (normal polarity) magnetization direction (formed before crustal folding) between Early Permian and Permian-Triassic Siberian poles, which indicates its Late Permian age. The normal polarity of the deposits indicates its formation in the period between Kiama superchron, characterized by reversal polarity, and Illavara hyperchron with mixed polarity - 265 Ma. Direction from Chernoyar suite is well-correlated with Late Triassic APWP of Europe, directions of magnetization are bipolar. From Hilok suite several sites show direction of magnetization similar to directions revealed from Early Cretaceous volcanites from nearby area. The magnetization is metachronous. In the other sites the directions of magnetization well-correlated with Late Jurassic APWP of Europe. In conclusion position of calculated poles for the Siberian platform and data for the European platform is pointed to full consolidation of northern Eurasia. The reported study was funded by RFBR according to the research project No. 16-35-00555 mol_a and grant of the Government of the Russian Federation No. 14.Z50.31.0017.
NEW DATA ON MAGNETOSTRATIGRAPHY OF PERMIAN-TRIASSIC STRATA FROM THE CENTRAL
EUROPEAN BASIN (GERMANY)
Fetisova A.M.1,2, Veselovskiy R.V.1,2, Scholze F.3
1 - Lomonosov Moscow State University 2 - Institute of Physics of the Earth RAS
3 - TU Bergakademie Freiberg, Institut für Geologie, Freiberg
We present a new detailed paleomagnetic data obtained from three representative Permian-Triassic Boundary (PTB) sections of Central European Basin, Germany – Nelben, Caaschwitz and Hergerhausen. The first two of these sections have been paleomagnetically studied previously (Szurlies, 2013) and our strategy was to get much more samples with small
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stratigraphic step in order to make stronger existing results. Hergerhausen section was sampled for paleomagnetic studies for the first time. In total we got 110 samples from each section with step ranges from 3 up to 50 cm. Results from Caaschwitz allow us to improve the reliability of local magnetostratigraphic scale and make it more detail. Paleomagnetic record from Hergerhausen section is hard to interpret, nevertheless it makes us possible to create a preliminary magnetic scale of this outcrop. Paleomagnetic data of a good quality has been obtained from Nelben section; in this study we use it to estimate an inclination shallowing factor by E/I method (Tauxe and Kent, 2004). All obtained data on magnetostratigraphy was compared with the Global Geomagnetic Scale. This study was funded by grants 15-05-06843 and 15-35-20599 (RFBR) and grant 14.Z50.31.0017 of the Government of the Russian Federation. Szurlies, M., Late Permian (Zechstein) magnetostratigraphy in Western and Central Europe // Geol. Soc. Lond. Spec. Publ. 2013. 376,73-85. Tauxe, L., Kent, D.V. A simplified statistical model for the geomagnetic field and the detection of shallow bias in paleomagnetic inclinations: was the ancient magnetic field dipolar? // In: Channell, J.E.T., Kent, D.V., Lowrie, W., Meert, J. (Eds.), In: Timescales of the Paleomagnetic Field, vol.145. 2004. American Geophysical Union, Washington, D.C, pp.101-116.
CENOZOIC MAGNETOSTRATIGRAPHIC SECTION OF THE ISHIM PLAIN (WEST SIBERIAN PLATE)
Gnibidenko Z.N., Kuz'mina O.B., Khazin L.B., Khazina I.V.
Institute of Petroleum Geology and Geophisics SB RAS
The results of the paleomagnetic and paleontological studies of Cenozoic sediments from cores of two boreholes drilled in the south of the Tyumen region (Ishim plain, West Siberian plate) are present. The Upper Eocene marine sediments (upper Tavda Suite), continental Oligocene-Miocene (Novomikhailovka, Turtas, Abrosimovka Suites) and Quaternary deposits (Smirnovka, Tobolsk and Susgun Suites) dissected in boreholes 1
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(Borodino) and 4 (Scripkino). Assemblages of dinocyst, spore-pollen and ostracods characterize these deposits. The biostratigraphic and paleomagnetic data show that the sediments formed in the Late Eocene (Priabonian) – Holocene time interval. Three hundred and fifteen oriented "top-bottom" samples from two wells have been studied. The component analysis of natural remanent magnetization, based on stepwise thermal and alternating field (AF) demagnetization allowed one to single out the characteristic component of magnetization (ChRM) corresponding normal and reverse polarity. Paleomagnetic sections of two wells were built based on this component. Based on palynological and paleomagnetic data these sections were tied in a key magnetostratigraphic section. Nine magnetosones have been established in this section: one (Rtv) – in Tavda Suite; four (N1nm, R1nm, N2nm, R2nm) – in Novomikhailovka; two (Ntt & Rtt) – in Turtas; one (Rab) – in Abrosimovka and one (N) – in the Quaternary. Analogues of the regional magnetosones of the Cenozoic scale of geomagnetic polarity of the West Siberian plate [Gnibidenko, 2006] and Chrons of Gradstein’s World magnetochronological scale [Gradstein et al., 2012] in the time interval from ~ 35.4 Ma to 10,000 yr. were identified in this section. Due to these researches, stratigraphic gaps in sedimentation were recorded. Considerable gap was recorded at the boundary of Eocene-Oligocene. The Atlym horizon (the Lower Oligocene) is absent in the Cenozoic sediments of Ishim plain. Oligocene is represented in a reduced volume. Long-term stratigraphic gap is confined to the boundary of the Oligocene-Quaternary sediments. The Miocene-Pliocene and Eopleistocene sediments are almost absent in these sections. Performed investigation represent an example of how having the polarity time scale for a certain time interval, it is easily to determine the age of studied sediments and to correlate them with the even-aged rocks of other regions.
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DEVONIAN AND LOWER CARBONIFEROUS PALEOMAGNETISM IN THE MAGNITOGORSK ZONE OF THE SOUTH URALS: PRELIMINARY
RESULTS
Golovanova I.V.1, Danukalov K.N.1, Matrosov V.Yu.1, Khidiyatov M.M.1, Bazhenov M.L.2
1 - Institute of Geology, Ufa Scientific Centre, RAS, Ufa 2 - Geological Institute, Russian Academy of Sciences, Moscow
This preliminary paleomagnetic research on igneous and volcano-sedimentary rocks undertaken within the Magnitogorsk zone on the eastern slope of the South Urals is aimed at clarifying paleogeographical and paleotectonic features of the South Urals during the Devonian and Lower Carboniferous. Altogether, we have tested about 1000 samples from seven Devonian and five Lower Carboniferous sections subdivided into 111 sites and performed their thermal demagnetization (up to 20 steps). Most of the Devonian samples under study show the post-folding intermediate-temperature (ITC) magnetic component that corresponds to the Late Paleozoic remagnetization spread widely in the Urals. The high-temperature, sometimes bipolar, magnetic component (HTC) can be recognized in a small number of sites, mainly in volcanic rocks and jasperoids. This component can be interpreted as the primary one; however, the problem will undoubtedly require further investigation. Some Lower Carboniferous samples from the Magnitogorsk-Bogdanovka Graben show the ITC that corresponds to the Late Paleozoic remagnetization and emerged shortly before folding or at the initial stages of deformation. Approximately one fourth of the sampled Lower Carboniferous lava flows show the bipolar HTC, with the direction close to the reference for the Lower Carboniferous of the East European Platform. If such HTC is possible to be recognized in a sufficient number of lava flows, it will allow the conclusion that the portions of the Magnitogorsk island arc in question were combined into a single entity with the continent by that time. The work was financially supported by grant 15-05-03036 from the Russian Foundation for Basic Research.
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PALEOMAGNETISM OF ORDOVICIAN-SILURIAN VOLCANIC ROCKS ON THE WESTERN SLOPE OF
THE SOUTH URALS: PRELIMINARY RESULTS
Golovanova I.V.1, Danukalov K.N.1, Bazhenov M.L.2
1 - Institute of Geology, Ufa Scientific Centre, RAS, Ufa 2 - Geological Institute, Russian Academy of Sciences, Moscow
There are very few paleomagnetic data on the Ordovician and Silurian Periods both for the western slope of the Urals and the East European Platform as a whole. A considerable part of rocks in the region got remagnitized in the Late Paleozoic. The main purpose of our study was to reveal new geological objects with a reliable age, which are still preserve their primary magnetization. In recent years, U/Pb zircon dating of Paleozoic rocks has been obtained by studying the age of magmatites in the Bashkir Meganticlinorium previously assigned to the Precambrian. As a result, a Late Ordovician-Silurian magmatic complex has been established. In one of the dated sites on the Ushat River, we have carried out reconnaissance paleomagnetic sampling. The section contains lava flows of sub-alkaline basalts with low-degree secondary alterations confined to the zone where the Lower Riphean Ai Formation is developed. The age of rocks in this section is 441.8±8.2 Ma and 437±11 Ma. We have taken 47 samples combined into 7 sites and conducted their stepwise thermal demagnetization (up to 20 steps). All these rocks are characterized by a strong magnetic signal. Permian remagnetization is almost absent in the samples under study. High-temperature component can be observed both in the narrow (560-580 to 680-700 °C) and broad (250-300 °C up to demagnetization) intervals and resides in magnetite and hematite. According to our calculations, the paleomagnetic pole has the coordinates 24.9° N and 198.8° E (24.9° S, 18.8° E), A95=13,6° showing a good agreement with the data on Baltica for 440 Ma. The obtained results give reason to hope that further research of Paleozoic volcanic rocks on the western slope of the South Urals will give us a new Ordovician-Early Silurian paleomagnetic determination to be used in identifying the APWP for Baltica in the Early Paleozoic.
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The research was performed under State Programme 0252-2014-0009.
TO THE ASSESSMENT OF THE IMPACT OF PROCESS OF SINGLE-PHASE OXIDATION AND SUBSEQUENT DECOMPOSITION OF TITANOMAGNETITES ON THE RESULTS OF PALAEOINTENSITY DETERMINATION
BY THE THELLIER METHOD
Gribov S.K., Dolotov A.V.
Borok Geophysical Observatory of Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, Borok, Yaroslavl
Region, Russia
Thellier-type experiments are the most widely applied approaches for determining the absolute palaeointensities of Earth's magnetic field from volcanic rocks. However, there are a number of factors that influence the accuracy of the assessments. Such factors include, among other, secondary remanences of chemical origin. But the question of their role in the distortion of palaeomagnetic data is still open. In the present study, basaltic samples (from Sao-Tome Island, West Africa) containing pseudo-single-domain titanomagnetite grains with Curie temperatures Tc~78 and 105 0C were heated in air during the 200-hour exposure at a given temperature (250, 300, 350, 400, 450 and 5000C) with the purpose to impart on the oxidation products of initial titanomagnetites either a CRM (isothermal chemical remanence) or a pTRM (partial thermoremanent magnetization) or a combination of both. These samples were then subjected to Coe-modified Thellier method which incorporated pTRM checks and pTRM tail checks; at that, the applied lab field was same as for CRM or pTRM acquisition. The aim was to compare the calculated “palaeointensity” with the true values and evaluate the possibility (or the futility) of recognition of CRM on the basis of an Arai-Nagata graphical construction of the Thellier-Coe procedure. The results of a simulated Thellier-Coe palaeointensity experiment shown that the error of determination of the field of “pure” pTRM is less than 10%, which is a reasonable level of uncertainty in palaeointensity
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estimates. In contrast, determination of apparent strength of the acquisition field of CRM by this method leads to an underestimation of its value from 29 to 55% as titanomaghemitization proceeds, and from 45 to 30% during the subsequent oxy-exsolution of metastable cation-deficient titanomagnetites. It also established that CRMs were virtually indistinguishable in their Arai-Nagata plots from true TRMs. From the point of view of the palaeomagnetic practice this means that volcanic rocks containing oxidized titanomagnetites and carrying chemical magnetization may be the source of significant error in determination the palaeostrength of the geomagnetic field by the Thellier method when a natural CRM is mistakenly interpreted as a TRM in the Thellier-type experiments. This work was supported by the RFBR (project no. 14-05-00365).
RE PALEOMAGNETIC STUDIES OF CARBONIFEROUS SEDIMENTS FROM OLD
COLLECTIONS (RUSSIAN PLATFORM)
Iosifidi A.G., Mikhailova V.A.
All-Russian Petroleum Research Exploration Institute(VNIGRI), St. Petersburg, Russia
The Carboniferous period has a duration of 60 million years. Paleomagnetic study of this period of history of our planet revealed a number of interesting features. In this time began the onward movement of the Russian platform to the North from Equatorial to temperate latitudes. According to various estimates, the speed of movement in the Carboniferous period is up to 5-10 cm/year. The behavior of the geomagnetic field has changed from a regime of frequent inversions to the predominance of reversed polarity – the beginning of hyperchrome Kiama (C2 – P2). Other features include the presence of mass extinctions of organisms at the boundary of Devonian-Carboniferous Lower and Upper Carboniferous (famennian – tournaisian and serpukhovian- bashkirian mass extinction). All of the above features of the Carboniferous period require more information about the behavior of the geomagnetic field in this geological period, which will allow us to more fully decipher the processes occurring inside the Earth and on its surface.
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Paleomagnetic investigations of Carboniferous sediments of the Russian platform was started in the late 50th and early 60th of the last century under the leadership of A. N. Khramov in the paleomagnetic laboratory of the VNIGRI. In the 50s-70s years, there were nearly 50 definitions for the Carboniferous sediments of the Russian platform. The quality of these data does not always meet the modern criteria of authenticity, which requires, as re-investigation existing and explore new collections of Carboniferous age. Another problem is that most of the definitions made by red sediments and it is possible to "lag" recording changes of the geomagnetic field up to a full remagnetization of the rocks in subsequent periods. Analysis of the results of paleomagnetic studies on Carboniferous sediments of the East European platform (EEP) shows the incompleteness of the available time series of paleomagnetic determinations. For the early Carboniferous (duration about 40 million years) is two times less than the definition corresponding to the modern criteria of authenticity than of late Carboniferous epoch (18 million years). We present the results of studying the paleomagnetic samples of Carboniferous rocks collected by A. N. Khramov and other staff of the paleomagnetic laboratory of the VNIGRI in the 50th-70th, from the Carboniferous deposits of the Russian platform. Our studies of the Carboniferous rocks have allowed obtaining a new paleomagnetic poles for the sediments of Gzhelian, Moscovian and Visean stages of the Carboniferous of the Russian platform. In red-colored sediments, Gzhelian and Moscovian stages identified components of natural remanent magnetization with a low inclination, which can be linked to the presence of large hematite particles or aggregates of particles caused by the electrostatic interaction of small magnetic particles, and the interaction of the magnetic and clay particles. The reconstructed trajectory of the apparent wandering of the paleomagnetic pole (APWP) for EEP allowed us to estimate its kinematic parameters in Carboniferous time. The total rotation angle is 36±6o at an average speed of 0.6 degree/million years (the pole of rotation: latitude 35oN, longitude 40oE), and the latitudinal shift of 13±7 at an average speed of 0.2 degree/million years (2.4 cm/year).
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STUDY OF SHORT MARINE MAGNETIC ANOMALIES
Ivanov S.A., Merkur'ev S.A.
St. Petersburg Branch of Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of the Russian Academy of
Sciences, St. Petersburg
Marine magnetic anomalies of the tiny wiggles (TW) type can be used to solve geohistorical and paleomagnetic problems. The model fields corresponding to Paleocene–Eocene anomalies in the northwestern Indian Ocean, which were formed during the fast spreading stage, were studied. For these fields, widely used interpretation methods were compared with a method proposed previously by the authors. The testing was performed with first the classical block model and then more complex models reflecting actual processes of oceanic accretion and magnetic field variations in the past. It was shown that the proposed method has advantages for this problem; it gives an error close to the minimum possible error and can adequately be used in interpretations. Spectral and statistical methods are used to estimate the magnetic anomaly resolving power and to study some factors that can exert a distorting influence. In addition, model examples have been used to indicate how the TW determination accuracy is affected by diurnal variations in the main magnetic field (MMF) and by ancient magnetization vector determination errors.
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APPLICATION OF PALEOMAGNETIC METHOD FOR STUDIES OF ROCKS AND PETROMAGNETIC MAP
COMPILATION (ARMENIA)
Karakhanyan A.K., Minasyan J.O.
National Academy of Sciences of the Republic of Armenia Institute of Geophysics & Engineering Seismology
The reliability of the geological interpretation of magnetic anomalies is directly dependent on the completeness and detail of our knowledge of the magnetic properties of rocks in the region. The study of magnetic, paleomagnetic and petromagnetic parameters (natural residual magnetize, magnetic susceptibility and the Curie point) of different types of rocks makes it possible to create petromagnetic and petrophysical classification of these rocks. As a result, it will be possible to interpret the nature of the anomalous magnetic field of deep faults, as well as the most prospective ore-bearing areas. For regions such as Armenia, the complexity of the geological mapping related to the conditions of formation of various complexes of rocks, which was mainly caused by multiple eruptions of large amounts of volcanic centers. Petromagnetic and paleomagnetic characteristics about 350 geological section and outcrops (5000 samples) are studied. The selection of petromagnetic groups of Phanerozoic rocks in Armenia is made by the statistical characteristics of the Curie point, the natural residual magnetization, magnetic susceptibility and genetic type of rocks. As a result, petromagnetic schematic map 1: 500000 scale is compiled.
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ABOUT THE NATURE OF STRIPE MAGNETIC ANOMALIES IN SUBDUCTION ZONES
Karimov F.H.
Institute of geology, earthquake engineering and seismology of the Academy of Sciences of the Republic of Tajikistan
At the beginning of the 1960s in the areas of mid-ocean ridges stripe magnetic anomalies were discovered. As has been shown after the detailed studies, these anomaly stripes represent alternating directly and inversely magnetized geological stripe-like structures. In the alternative theories of stripe magnetic anomalies it has been shown, that such abnormality may arise not only due to the inversion of the main magnetic field of the Earth, but as a result of self-magnetization of stripes while lava is cooling at the terms of geomagnetic field excursions. More clear the stripe magnetic anomalies both by magnitude and sharpness of boundaries are performed in areas that are closer to the axis of mid-ocean rift zones. As farther is the rocks’ disposition from these axes in both opposite directions the relevant magnetic anomaly is more blurred and at distances of hundreds of kilometers and more fades to the background values. Usually, these features of anomalies is interpreting as the manifestation of impact of hydro-chemical weathering of magnetic characteristics of the main minerals and rocks that form the ocean floor including the decay of magnetite and titanomagnetites during the geological time. However, in a number of studies it have been shown that, at least in some parts of the tectonic plates subduction zones, such as oceanic and continental ones, the stripe magnetic anomalies begin to manifest again. In this paper the possibility of such restoration of stripe-magnetic anomalies in these subduction zones is under the consideration. The essence of this recovery mechanism is in rising of the Earth interiors’ temperature as a result of internal friction, whilst oceanic plate submerging under the continental one, like is it in the Benioff zones. Increased volcanic activity in the areas of island arcs represents the interiors’ heating in subduction zones with initial temperatures of lava within 800-12000C interval, significantly higher than the Curie points for all major natural magnetic minerals, ranging within 300-7000C. After the initial lava cooling down to
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the temperatures below the blocking temperatures, as far as they are rising up and spill on the oceanic bottom, they acquire the primary magnetization in the direction of the present local magnetic field of the Earth and create own specific stripe arcuate magnetic anomaly along the island arcs, as well as the ring-shaped magnetic anomalies around volcanoes, concentric with respect to its axis of symmetry. Further on in the formation of stripe-magnetic anomalies with right and reverse directions, in principle, the self-magnetization mechanism can act in rock massifs at the times of geomagnetic excursions. The magnetization of oceanic basalts reaching so high values as 0.04 emu units facilitates such self-magnetization.
SLAVIN YAR KEY SECTION – NEW ROCK-MAGNETIC EVIDENCE OF VOLCANIC EVENTS IN
TRANSBAIKALIA
Kazansky A.Yu.1, Matasova G.2, Shchetnikov A.A.3, Filinov I.A.3, Chegis V.V.4
1 - Geological Faculty of Moscow State University, Moscow, Russia
2 - Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia
3 - Institute of the Earth's Crust SB RAS, Irkutsk, Russia 4 - IZMIRAN, Moscow, Russia
Slavin Yar key section of Late Quaternary deposits is located in Tunka depression of Transbaikalia (51°42’N, 102°39’E) and has the thickness about 30 m. It contains two absolute dates 37,790 ± 310 yr BP (14С AMS) and 45,810 ± 4,070 yr BP (14С) at the depth ~8 m и ~10 m. Rock-magnetic samples were taken every 5-10 cm up to 26.7 m (284 samples). 151 samples were also used for laser granulometry. Grain size analysis revealed different types of deposits: loess, paleosol, aeolian sand, slope and alluvial deposits. Rock-magnetic study has shown that the deposits contain a large number of SD magnetite grains; the proportion of samples with MD (Bcr/Br> 4) grains is less than 10%. To detect traces of volcanic events, we used the relationship between the median grain size from laser
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granulometry and effective magnetic grain size from rock-magnetic data, because for horizons free of volcanic material this relation is direct, whereas for horizons with volcanic particles it is reverse. Horizons with volcanic material have a well-defined position in the section and have the lowest (<3.1) values of Bcr/Bc ratio. Thus, we can recognize 2 stages of the volcanic activity in Slavin Yar section: i) at the end of the late Pleistocene (two major events with proximate ages of 26 kyr BP and 12 kyr BP) and ii) in the middle of the Late Pleistocene (> 46 kyr BP). This work was supported by the Russian Foundation of Basic Research, grants №№ 15-05-01811, 15-35-20293.
MAGNETIC ENHANCEMENT MECHANISM IN LATE QUATERNARY PALEOSOL FROM DAGESTAN
Kazansky A.Yu.1,2, Rybalko A.A.2, Matasova G.G.3, Kosterov A.A.4
1 - Geological Faculty of Moscow State University, Moscow, Russia
2 - Institute of Archaeology and Ethnography, Novosibirsk, Russia
3 - Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia
4 - St. Petersburg State University, St. Petersburg, Russia
Magnetism of loess-paleosol successions is a powerful tool to study of climate change in the past; however, in each case it is necessary to know which mechanism is responsible for the formation of magnetic properties. We tried to solve this problem for the loess-paleosol section Darvagсhay (42.1º N; 48.0º E) in Dagestan. The section contains paleosol (1.2 m) of Late Quaternary (MIS-5) age with underlying (4.8 m) and overlying (2.3 m) loess horizons. 74 rock-magnetic samples were taken every 5-10 cm. Rock-magnetic study has led to the following conclusions: 1) magnetic susceptibility in paleosol are 2-2.5 times higher than in loess: 2) FD susceptibility is less than 3% in loess and varies from 6 to 10% in paleosol; 3) Bc and Bcr in loess are considerably higher than in paleosol; 4) all
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sediments are characterized by PSD domain state. Such rock-magnetic behavior is typical for magnetic enhancement mechanism widespread in Chinese Loess Plateau and Europe [Evans, Heller, 2003]. According to this model, the magnetic particles in the loess are predominantly of aeolian origin and subject to little if any secondary changes. On the contrary, pedogenic processes in paleosol lead to neoformation of secondary magnetite grains of SP size. This work was partially carried out using the facilities of Geomodel Resource Center, St. Petersburg University and supported by RSF grant № 14-50-00036.
TWO TYPES OF IMPACT MELTS WITH CONTRASTING MAGNETIC MINERALOGY FROM
JÄNISJÄRVI IMPACT STRUCTURE, RUSSIAN KARELIA
Kharitonskii P.V., Kosterov A.A., Sergienko E.S.
St. Petersburg University
Paleomagnetic and rock magnetic studies of impact-related rocks can provide important constraints for deciphering geophysical records from suspected impact structures, their geochronology, and, in the case of very large impacts, their effect on the Earth as a whole. However, the paleomagnetic record in impact-related rocks may be ambiguous because of the uncertain origin of their natural remanent magnetization (NRM). Towards this end, we carried out a comprehensive rock magnetic and mineralogical study of tagamites (impact melts) from the Jänisjärvi astrobleme, Russian Karelia. Chemical composition of magnetic minerals and non-magnetic matrix was evaluated by SEM and X-ray analysis. Magnetic minerals were identified using thermomagnetic analysis at high and low temperatures, whereas their domain state was evaluated from hysteresis measurements and magnetic force microscopy. Jänisjärvi tagamites appear to belong to two essentially different types which result from the differences in the impact melt crystallization conditions. Type I tagamites were likely formed by an extremely rapid cooling of a super-hot
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melt with initial temperatures well above 2000°C. Type II tagamites originate from cooler and more iron-enriched melt. Common to the two types is that they both contain a substantial amount of so-called ore dust grains tens of nanometers to few μm in size, which appear to be a major, in some cases dominant, magnetic mineral carrying a significant part of rocks NRM. Structurally, ore dust grains are heterogeneous objects consisting of two phases showing both chemical and magnetic contrast. Theoretical estimates confirm that the observed magnetic properties of tagamites can be due to the ore dust.
MAGNETIC PROPERTIES AND FEATURES OF A MICROSTRUCTURE OF BARK OF MELTING OF THE
CHELYABINSK METEORITE
Korzinova A.S.
GO "Borok" of IFZ RAS
We studied a fragment of the Chelyabinsk meteorite. The size of a sample made 45х25х28 mm. The sample had rather thick bark of melting (to 7 mm). Bark of melting was of great interest to us because through it more than 99% of substance of a meteorite are processed. This substance gets to Earth and is fixed in sedimentary breeds and peat. Knowledge of features of this substance is necessary for us for identification of catastrophe events. Experiments were made on the cut melting bark fragments. By means of an electronic microscope of TESCAN VEGA II images were received, and the chemical composition of minerals in a sample was determined by power dispersive ranges. For definition of phase composition of bark of melting roentgenograms by means of the STOE STADI MP diffractometer with geometry on a gleam, Co-Kα radiation were made. Parameters of a loop of a hysteresis were received at the room temperature, and then heated up to 7750 C, with a speed of 80 of 0C/mines in external magnetic fields (tension to ±0.9 T) by means of the Variable Field Translation Balance device. The step thermomagnetic analysis of magnetization of saturation (Ms) on magnetic scales (the TAF-1 installation of a design of Vinogradov) at discrete heatings was carried out (v = 40C/sec.) in an interval temperatur25-7000C in constant external magnetic
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field by tension of 0.65 T. By means of Dai's chart [Dayetal., 1977] in hysteresis parameters (Mrs/Ms=0,01 from Bcr/Bc=11,6) it was established that samples contain multidomain grains of magnetic minerals. They are magnetosoft. By results of a research of curves Ms(T) four excesses corresponding to Curie's points were revealed. In total with results of the X-ray phase analysis and electronic microscopy them it is possible interpreted as T=3120C – pyrrhotine (close to a troilite), T of =3900C-taenite, T of =5800C magnetite, T =7600C-kamacite. In melting bark samples the share of a troilite made 7,4%, a taenite – 7%, magnetite – 5,1%, a kamacite – 7,1%, a forsterite – 73,4%. Work is performed with assistance of the Russian Federal Property Fund, projects 16-05-00703a
MAGNETIC PROPERTIES AND MICROSTRUCTURE FEATURES OF THE FUSION CRUST OF THE
CHELYABINSK METEORITE
Korzinova A.S., Tselmovich V.A.
Borok Geophysical Observatory is a branch of Shmidt's Institute of Physics of the Earth
One of the Chelyabinsk meteorite fragment transferred for Borok Geophysical Observatory In 2014. This fragment has a thick layer of the fusion crust (about 7 mm). The experiments conducted on sawn only fragments of the fusion crust. Images were obtained by dint of a scanning electron microscope image TESCAN VEGA II (shooting conditions V = 20 kV, I = 0.2 nA, the size of the probe beam 2mkm ~.). The chemical composition of minerals in the sample defined for energy-spectra. The diffractogram pattern of the sample obtained by X-ray diffractometer with STOE STADI MP with the geometry to the light, Co-Kα radiation. Hysteresis loop parameters obtained at room temperature and then heated to 775 ° C, to the speed 80 ° C / min in an external magnetic field (up to ± 0.9 tension T) via the device Variable Field Translation Balance.
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Step thermomagnetic analysis saturation magnetization (Ms) conducted on the magnetic scale (setting TAP-1 design Vinogradov) at discrete heatings (v = 4 ° C / sec) in the temperature range 25-700 ° C in a constant external magnetic field of 0.65 Tesla. Using diagrams Dai [Day et al., 1977] by hysteresis parameters (Mrs / Ms = 0,01 of Bcr / Bc = 11,6) determined that the samples contain grains multidomain magnetic minerals which are magnetically soft. The study of curves Ms (T) four inflection found, presumably corresponding to the Curie point. Taken together with the results of X-ray diffraction and electron microscopy it can be interpreted as T = 312 ° C - pyrrhotite (close to troilite), T = 390 ° C - taenite, T = 580 ° C -magnetit, T = 760 ° C - kamacite. The fusion crust samples troilite share of 7.4%, taenite - 7% magnetite - 5.1%, kamacite - 7.1%, forsterite - 73.4%.
THE ENVIRONMENTAL HISTORY OF LAKE HOVSGUL, MONGOLIA, BASED ON A PHYSICAL
INTERPRETATION OF REMANENT MAGNETIZATION ENDMEMBERS
Kosareva L.R.1, Shcherbakov V.P.1,2, Nourgaliev D.K.1, Fabian K.3
1 - Institute of Geology and Petroleum Technologies, Kazan (Volga region) Federal University
2 - Geophysical Observatory Borok IFZ RAS 3 - Geological Survey of Norway
Acquisition curves of isothermal remanent magnetization for 1017 samples of core KDP-01 from Lake Hovsgul (Mongolia) are decomposed into three meaningful endmembers using non-negative matrix factorization. The obtained mixing coeffcients also decompose hysteresis loops, back-field and strong-field thermomagnetic curves into their related endmember components representing mineralogical fractions of the Lake Hovsgul sedimen tary environment. A low-coercivity component with a co-varying paramagnetic phase results from a coarse grained magnetite fraction
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indicating terrigenous influx via fluvial transport. A second component has high-coercivity of about 50 mT and indicates a sharply defined magnetite grain-size fraction related to magnetosomes of magnetotactic bacteria. The third component has an even higher coercivity of about 85 mT and is identified as a biogenic greigite common in suboxic/anoxic sediments. The express character of deriving these data offers new possibilities for applying methods of rock magnetism in the paleoecological and paleoclimatic studies. Significant positive correlations between variations of intensity of all three mineralogical components along the core are found. A dramatic decrease in intensities of all endmembers detected near the depth of 20 m testifies to a major event occurred in the environmental/geological history of surroundings of the Lake Hovsgul, possibly it marks the termination of arid climate conditions. Rare intervals of high total productivity of magnetotactic bacteria are characterized by abundance of magnetite magnetosomes and can be considered as markers for glacial-interglacial transition intervals. For the rest of the core the greigite concentration substantially exceeds that of magnetite, most possibly due to a predominance of anoxic environment caused by onset of icy climatic conditions.
EVALUATION OF STABILITY OF PALEOMAGNETIC SIGNAL FROM ROCKS WEATHERED IN
CONDITIONS OF WAVE-CUT ZONE
Kulakova E.P.1, Veselovskiy R.V.1,2
1 - Lomonosov Moscow State University 2 - Institute of Physics of the Earth, Russian Academy of
Sciences
There are two methods of paleomagnetic sampling: "manual" method of taking samples with using geological hummer and "core" method with using Pomeroy’s portable drill. When we use portable drill, we can get less weathered parts of rocks from the depth. In terms of paleomagnetic researches it is important to know the depth of sample selection in order to study primary paleomagnetic signal from the rocks not altered by surface
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weathering. So, the main aim of this work was to evaluate the stability of paleomagnetic signal (direction of the natural remanent magnetization) depending on the depth of sampling (weathering degree). The objects of studies were Devonian dykes, which are widely spread over the Kola peninsula. 10 cores from the 6 dykes located in wave-cut zone of the Barents and White Seas (zone of high influence of chemical and physical weathering) were selected for the experiment. This work concerned the comparison of paleomagnetic characteristic and rock magnetic properties of samples from different parts of the same drill core. 6 out of 10 cores show that the weathering degree does not influence appreciably on preservation of the paleomagnetic record. However, 4 cores demonstrate the changing of the direction of natural remanent magnetization from the present-day in higher samples to the Devonian direction in lower samples (4-6 centimeters). Thus, sampling for paleomagnetic studies in aggressive conditions of surface chemical and physical weathering (wave-cut zone) is necessary to make from less weathered parts of the rocks, so, using of the portable drill is preferable.
ANISOTROPY OF MAGNETIC SUSCEPTIBILITY OF THE DOLERITE SILLS FROM THE ANGARA-
TASEEVA DEPRESSION (THE SIBERIAN PLATFORM) AND ITS IMPLICATION FOR THE MAGMA
EMPLACEMENT RECONSTRUCTION
Latyshev A.V.1,2, Ulyahina P.S.2, Veselovskiy R.V.2,1, Mirsayanova E.M.2
1 - IPE RAS, Moscow 2 - MSU, Moscow
The Siberian Trap (“flood basalt”) province covers vast areas on the Siberian platform (the Tunguska syncline and surrounding areas) and in the adjacent fold belts. Within the Angara-Taseeva depression (the southern part of the Siberian platform) the products of the Permian-Triassic magmatic activity represent large dolerite sills located in the Paleozoic sediments of the Siberian platform. In spite of the continuous study of these
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intrusions, their age, correlation with lava sections and the order of emplacement remains uncertain as well as the extension of the discrete bodies. Based on the detailed paleomagnetic investigation we distinguished several brief and powerful magmatic events corresponding to the large sills: the Padunskiy, Tulunskiy and Tolstomysovskiy. The emplacement of the Tolstomysovskiy sill and associated tuffaceous packs was coeval to the main phase of the volcanic activity in the Siberian platform, while the formation of the Padunskiy sill and related intrusions took place just after the termination of the main stage of volcanism. Then we performed the detailed research of the anisotropy of magnetic susceptibility (AMS). The majority of studied sites demonstrated so-called “normal magnetic fabric” for sills (e.g. Dragoni et al. 1997): the minimal axis of AMS ellipsoid is subvertical and normal to the contact, the two other axis are shallow. Interpreting the orientation of the maximal axis as the magma flow direction, we can determine the feeding zone of sills locating in the central part of the Angara-Taseeva depression. In addition, the obtained data does not confirm the idea of single large sills extending over the whole depression: the directions of the AMS lineation form several “half-moons” converging to the discrete centers which could be the local zones of magma rising and intruding. This study was funded by RFBR (projects № 16-35-60114, 15-35-20599) and the Ministry of Education and Science RF (project № 14.Z50.31.0017).
THE MODERN MAGNETIC MEASUREMENT EQUIPMENT FOR ARCHEOMAGNETIC RESEARCH
Legoff M.
IPGP
In this work we presented the modern magnetic measurement equipment for archeomagnetic and paleomagnetic research.
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MORE STABLE YET BIMODAL GEODYNAMO DURING THE CRETACEOUS SUPERCHRON?
Lhuillier F.1, Gilder S.A.1, Wack M.1, He K.1, Petersen N.1, Singer B.S.2, Jicha B.R.2, Schaen A.J.2, Colon D.2
1 - Department of Earth and Environmental Sciences, Ludwig-Maximilians-University, Munich, Germany
2 - Department of Geoscience, University of Wisconsin, Madison, USA
We report palaeomagnetic and 40Ar/39Ar dating results from two sequences of basaltic lava flows deposited at the same locality in western China, yet separated in time by ~50 Myr: one set lies within the Cretaceous normal superchron at 112-115 Ma and a second at 59-70 Ma spanning the Cretaceous-Palaeogene boundary. We find that magnetic field directions during the superchron exhibit bimodal populations: one with inclinations representative of a dipolar field and another with shallow inclinations that could reflect a more complex, multipolar field. However, the time-dependent variability in field directions was 50% lower during the superchron than after, which implies greater field stability during the superchron. Our results suggest that the field geometry could be more complex during superchrons than previously considered and raise the question whether a second, more multipolar, field state could be more persistent than previously thought.
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RELATIONSHIP BETWEEN ROCK-MAGNETIC AND GRAIN SIZE DATA FROM EARLY QUATERNARY SECTION "TOGAY" (OLKHON ISLAND, BAIKAL
LAKE)
Matasova G.G.1, Kazansky A.Yu.2, Shchetnikov A.A.3, Filinov I.A.3
1 - Trofimuk Institute of Petroleum Geology and Geophysics SB RAS, Novosibirsk, Russia
2 - Geological Faculty of Moscow State University, Moscow, Russia
3 - Institute of the Earth's Crust SB RAS, Irkutsk, Russia
78 samples from Togay section (53º09’ N, 107º13’ E; Olkhon Island, Baikal Lake) were subjected to combined rock-magnetic and grain size analysis. The section is 7.5 m thick and contains pedocomples with 3 humic horizons which are underlain by subaerial deposits and overlain by slope deposits. The highest values of magnetic susceptibility (up to 192*10-5 SI) are found in humic horizons of pedocomplex, where FD susceptibility is also high (up to 13%). The behavior of concentration-dependent parameters is well correlated with the content of clay fraction in sediments (correlation coefficients R2 vary from 0.68 up to 0.83), while magnetic grain size (Bcr/BC ratio) is tightly connected with median grain size (R2= 0.66) and sand fraction (R2= 0.62). It means that magnetic properties are mainly determined by clay fraction and are resulted from secondary neoformation of magnetic minerals, while the effective size of magnetic grains is governed by coarse-grained magnetic particles of aeolian origin. The revealed relationship between the rock-magnetic and grain-size parameters is not typical for the Quaternary deposits from Transbaikalia (and Siberia as a whole), where the magnetic properties are mainly related to the silt fraction. Most likely it is connected with different climatic conditions in during Late and Early Quaternary time
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GEOMAGNETIC FIELD INTENSITY VARIATIONS AROUND TOWN TAMAN IN THE SECOND HALF OF
THE FIRST MILLENNIUM BC
Nachasova I.E., Pilipenko O.V., Markov G.P.
Institute of Physics of the Earth RAS
Archeomagnetic research of samples collection from archaeological monument- settlement Hermonassa (Taman Peninsula, the middle of I millennium B.C. - beginning I millennium A.D.). The aim of this study is to obtain geomagnetic field intensity data. A modified method of Thellier was used to determine the intensity of the ancient geomagnetic field. The archeological material was selected by layers from the south wall of the northeast of the section excavation. The determined geomagnetic field intensity lies mainly within interval - 90 - 60 µT. The average level of the geomagnetic field (about 80 µT) some changed during the time interval: the end VI - V century B.C. Then the field intensity began to decline. The average value of the field intensity from the data obtained by the material of two final layers of the monument become significantly lower (about 65 µT). Consideration of all geomagnetic field variations data obtained previously and now in the area of the Taman Peninsula in the time interval of the last 2500 years allow us to conclude that the nature of a smooth variation of the geomagnetic field is changing in time. The highest value of the geomagnetic field intensity reaches in V century B.C. In the first millennium A.D. the average level of geomagnetic field intensity varies little throughout the millennium, remaining significantly below the high level of I millennium B.C. In the last millennium the main trend of the change of the intensity of the geomagnetic field is droop. This work was supported by RFBR (grant N 16-05-00378) and the Russian Federation Government (grant N14.Z50.31.0017).
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MAGNETIC PROPERTIES OF ROCKS OF THE SOLAR PROSPECTIVE AREA OF THE SUGOYSKY FOLDED
ZONE NORTHEAST OF RUSSIA
Naumov A.N., Burnatny S.S., Ivanov Yu.Yu.
North-East Interdisciplinary Scientific Research Institute n. a. N. A. Shilo, Far East Branch, Russian Academy of Sciences
The Solar prospective area is located within the Sugoysky folded zone. In a geological structure the area is put by sedimentary rocks of the Verkhoyansk complex which are hornfels, sulfidized and metasomatic. Samples for rockmagnetic investigations for the purpose of interpretation of magnetometric data were taken. Magnetic properties more than 200 nonoriented samples of hornfels rocks, granodiorites, diorites and veins rocks are presented. Natural remanent magnetization (NRM) is measured on JR-5A spin-magnetometer, magnetic susceptibility (MS) and research it at high temperatures is carried out on a multifunction kappabridge MFK1-FA with the CS-3 high temperature control unit. Data showed a big variety of values of NRM and MS, depending on type of rocks and extent of their subsequent changes. Values of NRM of hornfels rocks varies from 0,24 to 808500 x 10-3 SI; MS - from 0,03 to 744,90 x 10-3 SI. For intrusive rocks NRM varies from 0,13 to 14288,39 x 10-3 SI; MS - from 0,01 to 65,87 x 10-3 SI. The highest values of NRM and MS are for hornfels rocks which show pyrrhotite (monoclinic and hexagonal) mineralization. These rocks may be sources of magnetic bipolar anomalies.
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A PRELIMINARY PALEOMAGNETIC, ROCK MAGNETIC, LOW FIELD AMS AND PETROLOGICAL
STUDIES OF THE MAFIC DYKES FROM THE NORTHERN PART OF SINGHBHUM CRATON,
EASTERN INDIA
Nishad R.K., Pradhan S.K., Patil S.K., Sinha A.K.
Dr. K. S. Krishnan Geomagnetic Research Laboratory, IIG, Jhunsi, Allahabad – 221 505
We report a preliminary result of paleomagnetism, rock magnetism and anisotropy of magnetic susceptibility (AMS) and petrological investigations on NW-SE and NE-SW oriented 17 dolerite dykes (60 oriented block samples) collected from northern part of the Singhbhum craton, India. The block samples were cored and cut into 682 standard size specimens. The natural remanent magnetization (NRM) intensity, magnetic susceptibility and Q-ratios were measured on all the specimens and noticed the ranges varies between 1.26 x 10-3 to 2.97 x 101 A/m, 542.27 to 2834.27 x 10-6 SI and 0.07 to 579.26 respectively. The mean values for NRM, magnetic susceptibility and Q-ratios were found as 3.02 A/m, 1142.49 x 10-6 SI and 55.80 respectively. Detailed AF pilot demagnetization technique was applied on representative 65 pilot specimens to yield characteristic remanent magnetic directions. It was observed from AF demagnetization curves that secondary component was removed at or around 300 Oe AF field steps. The primary component or characteristic remanent magnetization (ChRM) component was isolated through 350 to 600 Oe AF field steps. On the basis of pilot studies, further 165 specimens were subjected to AF blanket study (350, 400, 500 Oe) to obtain statistically significant groupings from the specimens. Out of the studied 17 dykes, 11 dykes have yielded statistically significant stable directions. The isolated ChRM direction was obtained as D=231.43, I=-38.47 (α95=17.35, k=7.89. The calculated virtual geomagnetic poles (VGP) are 23.20°N, 213.76°E (dp=12.22°, dm=2.59°) for these dolerite dykes. On the basis of the obtained VGP, these dolerite dykes paleomagnetic age is inferred in and around 2100Ma. The rock magnetic study comprising of isothermal
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remanent magnetization (IRM), Lowrie-fuller test, Q-ratios, Susceptibility versus high temperature (K-T) experiments indicate magnetite of PSD/SD type is the main magnetic mineral carrying the primary component in these studied dykes. Petrological study suggests that the dykes are medium to coarse grained in nature and the major mafic mineral consists of is clinopyroxene and calcic plagioclase with a distinct ophitic to subophitic texture. Replacement of chlorite and actinolitic is noticed in many samples. The opaque mineral constitutes 3-7% of the total volume. The low filed AMS study which was conducted on 611 specimens indicates the presence of Prolate and Oblate shaped magnetic grains in equal proportion. The magnetic foliation planes defined a “normal magnetic” fabric in the dykes.
THE NEW PALEOMAGNETIC DATA FROM UPPER RIPHEAN KHAYPAKH FORMATION (OLENEK
UPLIFT)
Pasenko A.M.
Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences
Late Riphean time is one of the key stages in the Earth's geological history. This period is marked by the existence and the disintegration of the Rodinia supercontinent [Li et al.,2013], the biological revolution, and complete (possibly) glaciation of the Earth [Corsetti et al., 2006]. The studies of paleomagnetism of Upper Riphean rocks help to solve the problem of the reconstruction of Rodinia, to describe the behavior of the earth's magnetic field in the studied time interval, to correlate the Riphean deposits of the Siberian platform. On the territory of the Siberian platform the Upper Riphean deposits are described on the territory Udzha, Olenek and Kharaulakh uplifts. Paleomagnetism of the Upper Riphean Formations of northern part of the Siberian Platform was investigated by Gurevich [Gurevich, 1983], Rodionov [Rodionov, 1984] and Osipova [Osipova, 1983]. Data, obtained by these researchers showed the possibility and the need for detailed paleomagnetic studies of the Upper Riphean rocks of Olenek uplift, using
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modern techniques and equipment [Konstantinov et al., 2007]. In this report we present new results of the paleomagnetic study of the Upper Riphean stromatolite limestones from the top of the Khaypakh formation (Olenek uplift) and discuss their significance for elaboration of the Late Riphean segment of the Siberian Apparent polar wander path and for Late Riphean paleotectonic and paleogeographic reconstructions. References 1. Gurevich E.L. Paleomagnetic studies of Precambrian sediments of north of the Siberian platform. - In the book: Paleomagnetism of the Upper Precambrian of the USSR. Proceedings VNIGRI, L., 1983, p.39-51 [in Russian] 2. Konstantinov K.M, Pavlov V.E, Petukhova E.P etc. The results of reconnaissance paleomagnetic studies of rocks of Udzha Uplift (northern Siberian Platform) // paleomagnetism and rock magnetism:. Theory, Practice, eksperiment: Materials of the seminar. M .: GEOS, 2007, pp. 69-72 [in Russian] 3. Osipova E.P. The problem of correlation of the Upper Precambrian paleomagnetic Siberian and North American platforms. -In the book: Paleomagnetism of the Upper Precambrian of the USSR. Proceedings VNIGRI, L., 1983, s.89-97 [in Russian] 4. Rodionov V.P. Paleomagnetism of the Upper Precambrian and Lower Paleozoic near of the Udzha river // paleomagnetic methods in stratigraphy. L .: VNIGRI, 1984, pp 18-28. [in Russian] 5. Corsetti F.A., Olcott A.N, Bakermans C., The biotic response to Neoproterozoic snowball Earth., Palaeogeography, Palaeoclimatology, Palaeoecology 232 (2006) 114–130 6. Li, Z.-X., Evans, D.A.D., Halverson, G.P., 2013. Neoproterozoic glaciations in a revised global paleogeography. Sed. Geol. 294, 219–232.
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NEW PALEOMAGNETIC DATA FROM THE NORTHERN PART OF THE UCHUR-MAYA REGION
(EASTERN MARGIN OF THE SIBERIAN PLATFORM) FURTHER SUPPORTS THE COEXISTENCE OF
SIBERIA AND LAURENTIA WITHIN ONE SUPERCONTINENT AND RAPID APPARENT POLAR WANDER DURING THE LAST 100 MILLIONS YEARS
OF THE MESOPROTEROZOIC
Pavlov V.E., Novikova A.S.
Institute of Physics of the Earth, RAS
We present the result of paleomagnetic studies which have been carried out on one of the classical Riphean sections exposed along the valley of the Belaya (Khanda) river (Uchur-Maya region, eastern Siberian platform). These studies encompassed the Totta formation, the Malgina formation (uppermost Mesoproterozoic) and the Lakhanda series (lowermost Neoproterozoic). The isolated high temperature components of natural remanent magnetization successfully pass a fold-test (the Totta formation), a reversal test ( the Malgina formation) and are in very good agreement with the general drift of the paleomagnetic pole, obtained earlier (Pavlov, 1994; Gallet et al., 2000; Pavlov et al., 2002) for southern sections of the Uchur-Maya region, exposed several hundreds kilometers apart. These data allow to suggest a new composite Uchur-Maya apparent polar wander path, which being compared with coeval segment of the Laurentian APWP convincingly confirms that Siberia and Laurentian have been a part of a single continent (Rodinia) and that the velocity of apparent polar wander at the end of the Mesoproterozoic was unusually high.
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DISTRIBUTION OF METALLIC IRON IN PLANETS
Pechersky D.M.1,2, Kuzina D.M.2
1 - Institute of Phyics of the Earth, RAS, Russia 2 - Kazan Federal University, Russia
The work represents an overview and generalization of the microprobe and thermomagnetic data on the investigations of content and composition of metallic iron in terrestrial rocks (upper mantle hyperbasites that carried at the Earth's surface by basalt lavas in the form of xenoliths from Antarctica, Mongolia, Primorye (Russian Far East), Syria, Spitsbergen and the Vitim Plateau (Russia); traps of Angarsk, Maimecha-Kotui and Norilsk provinces of the Siberian platform; oceanic basalts that form the floor of the Atlantic, Pacific and Indian Ocean, the Red Sea ) compared to the data for metallic iron from lunar basalts [Nagata et al.,1974] and meteorites [Pechersky D.M. et al., 2012]. It was found that the metallic iron particles contained in all groups terrestrial and extraterrestrial rocks are similar in composition, shape, and grain size. This similarity suggests the similar sources of these particles origin. This means that the terrestrial conditions were close to the conditions that existed at the source planets of the meteorites, e.g., the bodies from the asteroid belt which have been subsequently disintegrated, and crushed into interplanetary dust, which has fallen into the Earth surface. This similarity originates from the homogeneity of the gas-dust cloud at the early stage of the Solar System and obviously other star-planetary systems and subsequent gravitational differentiation in the process of all planet formation. Nagata N., Sugiura N., Fisher R.M., Schwerer F.C., Fuller M.D., DunnJ.R. Magnetic properties of Apollo 11-17 lunar materials with special reference to effects of meteorite impact // Proceedings of the Fifth Lunar conference. 1974. Vol.3, pp.2827-2839. Pechersky D.M., Markov G.P., Tselmovich V.A., Sharonova Z.V. Extraterrestrial magnetic minerals // Physics of the Earth, 2012, №7-8, p.103-120.
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NEW ARCHEOMAGNETIC RESEARCH OF POTTERY FROM NEOLITHIC SETTLEMENT SAHTYSH-I (IVANOVO REGION, RUSSIA) C. 5000-2000 BC
Pilipenko O.V.1, Nachasova I.E.1, Markov G.P.1, Gribov S.K.2, Tsetlin U.B.3
1 - Institute of Physics of the Earth RAS 2 - Geophysical observatory "Borok" of IPE RAS
3 - Institute of archeology RAS
This work is devoted to the archeomagnetic study of fired ceramic samples of Neolithic settlement Sahtysh -I to obtain data of geomagnetic field variations in the past. The study collection of pottery fragments were represented by six Neolithic cultures. The thermomagnetic analysis in dependence of the saturation magnetization and magnetic susceptibility on temperature and determination of the Curie points, and the powder method X-ray diffraction were carry out. The main carrier of the magnetization of the samples is relatively resistant to heat maghemite. The size of grains lies in PSD area. Those ceramic samples that showed strong chemical and mineralogical changes during heating were excluded from further experiment. The determination of the ancient magnetic field intensity was carried out by Thellier method. Age pottery fragments studied sequences corresponds to the Neolithic and lies within ~ 5000-2000 BC. Based on the carbon-isotope dating of sediments the chronology of Neolithic cultures of the Center of Russian plain was carried out. It is possible to link the selected layers to the data of the carbon-isotope dating of sediments using this chronology. The comparison of the variations of the ancient magnetic field depending on the age of the studied ceramics from Sahtysh - I section with archeomagnetic data from Iberian Peninsula and Siberia was fulfilled. Underestimation field magnitude may be due to the fact that the magnetite particles contained in the ceramic during heating in air in the past, oxidized to maghemite, which resulted to a thermochemical magnetization whose magnitude below thermoremanent magnetization. The study was funded by RFBR, project N 16-05-00378.
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PALEOMAGNETIC STUDIES OF THE REFERENCE SECTION OF THE LOWER CARBONIFEROUS OF
MSTA RIVER
Popov V.V.1,2, Sergienko E.S.1, Iosifidi A.G.2, Mikhailova V.A.2
1 - SPBU 2 - VNIGRI
Carboniferous period is one of the insufficiently studied in the paleomagnetic intervals respect geological history of the Earth. Paleomagnetic studies of Carboniferous sediments of the Russian platform was started in the late 50's and early 60-ies of the last century under the leadership of A. N. Khramova in the paleomagnetic laboratory of the VNIGRI. The quality of these data does not always meet the modern criteria of authenticity, which requires, as re-investigation existing and explore new collections of Carboniferous age. Analysis of the results of paleomagnetic studies on Carboniferous sediments of the East European platform shows the incompleteness of the available time series of paleomagnetic determinations. For the early Carboniferous (duration about 40 million years) is 2 times less than the definition corresponding to the modern criteria of authenticity than of late Carboniferous epoch (18 million years). The paper presents the results obtained for a new collection collected by paleomagnetologists of SPGU and VNIGRI in 2014, from reference sections of the upper Visean and Serpukhov deposits that are in the vicinity of Borovichi of the Novgorod region, in the basin of the river Msta. Rocks collected from six outcrops and represented by limestones and clays. According to the magnetic mineralogical analysis identified the main magnetic minerals, carriers of natural remanence. In the first stage of the work laboratory investigation (cleaning alternating magnetic field) allowed us to isolated two components of natural remnant magnetization(Jn). Jn the first component shows the presence of late Paleozoic remagnetization as clay and limestone (85% of the studied samples). Jn the second component gives the direction corresponding to the poles early Carboniferous of the Russian platform (325-318 million years).
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PERMIAN-TRASSIC REMAGNETIZATION OF BALTURINO FM.(LOWER SILURIAN, PRESAYANS): POSSIBLE IMPLICATIONS ON THE DURATION OF
TRAP EMPLACEMENT
Powerman V.I., Shatsillo A.V., Latyshev A.V.
IPE RAS, Moscow, Russia
We have collected 54 samples from the redbeds of Lower Silurian Balturino Fm. (Presayans, SE Siberia).All samples possess strong paleomagnetic signal, characterized by a single high-temperature component,decaying towards the origin on vector diagrams.High-temperature component was isolated in all samples. The mean direction (N=56,Dg=253.4,Ig=-62.1,Kg=133.6,a95g=1.6,Ds=254.2,Is=62.4, Ks=148.4, a95s=1.6) was used to calculate a paleomagnetic pole(plat=43.1,plon=171.6,dp/dm=1.9/2.5), which is located far from any known mid-Paleozoic paleomagnetic poles for Siberia, but relatively close to known Perm-Triassic pole for Siberia[Pavlov et al.,'07], implying trap-related remagnetization.This event had to take place during a reversed polarity epoch.The pole is indistinguishable on 95% conf. level from the (1)pole of Ivakinsk Fm. from the base of Noril'sk trap section [Heunemann et al., '04];(2)pole of Tulun sill, located relatively close to the Balturino area [Latyshev et al., '13]. Balturino pole is similar to the pole of Daldykan intrusive complex, which cuts the whole Noril'sk section.Therefore, the remagnetization pole is similar to both the pole acquired from the base of traps and to the pole of an younger intrusion, cutting the whole trap section.So, the available data is insufficient to univocally say when exactly the remagnetization had happen. It's worth discussing the significant differences between poles acquired from negative polarity directions and the average pole for the Siberian traps. One of the possible reasons for the absence of antipodality of paleomagnetic components in traps can be the complex geomagnetic field's structure at Paleozoic-Mesozoic boundary. Geomagnetic field at 359-207Ma used to have a long-lived component, corresponding to the equatorial dipole that was causing the non-antipodality[Khramov, '07]. It's also possible that the poles,significantly
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different from the mean trap pole and acquired from the rocks that had been magnetized during reversed polarity epochs, are younger than the main trap mass.This hypothesis is in a conflict with the data from lowermost Ivankinsk Fm. It is also possible that remagnetization happened too quickly to average secular variations. Tight clustering of isolated paleomagnetic components along with statistical differences between mean and expected direction (as estimated from the mean pole)might indicate a high speed of remagnetization and, subsequently, a rapid (100's-1000's years) emplacement of traps. This research was funded by RFBR grants #15–55–10055,16-35-60114,and by grant 14.Z50.31.0017 from the Gov. of Russia
EARLY SOLAR SYSTEM, PALEOMAGNETIC FIELD AND THE BIOSPHERE: CURRENT ISSUES
Ragulskaya M.V., Obridko V.N., Hramova E.G.
IZMIRAN
The geomagnetic field existence is one of the important factors in the origin and development of life on Earth. The geomagnetic field existed 4.2 billion years ago (according to recent paleomagnetic data, Tarduno, 2015). Its value was comparable to modern values. However, the dynamo theory can calculate of the geomagnetic field only up to 1 -1.5 billion years ago. But this contradicts the paleomagnetic data. Modern Earth's magnetic field is realized through compositional convection and separation of the solid and liquid core. Thermal convection is possible without a solid core, but it does not provide the necessary field values. In the dynamo - models a solid core appeared subsequently 2 bl. years ago and it has steadily increased in size. This factor provides the increase of the magnetic field to modern values. The dynamo theory it is assumed that up to 2 billion years ago the geomagnetic field is absent or was much less modern (Pavlov, Reshetnyak, 2015). There are alternative theories appearances of a solid core at the same time with the Earth. The liquid core geosphere was formed of external parts of the planet and slowly destroys the protocore by means of the surface erosion. The silicate chondrite material liberated by this way floats-up through metallic melt and generates composite convection, which mainly supports geodynamo. The model
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calculations demonstrate that gravitational energy of such floating is sufficient for overheating of the lower mantle basement and for the plume formation. According to this theory, the value of the ancient geomagnetic field 4 billion years ago was comparable to the modern, then decreased to almost zero for about 2 billion years ago, and subsequently again gradually increased to today's values. This is due to the decrease and increase in size of the solid inner core (Pushkarev, Starchenko, 2013). However, both of these directions in the Earth's magnetic dynamo theories consider the Earth as a closed isolated system. Do not take account many aspects of solar - terrestrial relations, for example there is a hypothesis of the early Earth movement through the solar system and the migration of massive Jupiter near the inner planets. Questions about the influence of the early sun dynamic and the solar system parameters on the paleomagnetic field and the development of life on Earth are discussed.
NEW ARCHEOINTENSITY DATA FROM NORTH WESTERN AND CENTRAL RUSSIA BETWEEN 12
AND 19 CENTURY AD
Salnaia N.1, Gallet Y.2, Antipov I.3, Genevey A.4
1 - Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
2 - Institut de Physique du Globe de Paris- Sorbonne Paris Cité- Université Paris Diderot, UMR 7154 CNRS, Paris, France
3 - Archeology Dept., St Petersburg State University, St Petersburg, Russia
4 - Sorbonne Universités, UPMC Univ Paris 06, CNRS, UMR 8220
In this study we presented the previously archeointensity results for North-Western and Central parts of Russia. The collections consist from baked-clay brick fragments were sampled during recent excavations, mostly at church and monastery nearby. All archeomagnetic sites were precisely dated thank to historical chronicle between 12 and 19 century AD. Rock magnetic measurements show that main magnetic minerals are
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(titano)magnetites with different includes of hematite. Paleointensity experiments were conducted by two protocols: special technique developed for three-axis magnetometer (see Le Goff, Gallet, 2004) and Thellier-Coe method with pTRM checks (Thellier, Thellier, 1959; Coe et. al, 1967). We determine several groups of paleointensity mean value that will be comparing with the available global and regional geomagnetic field models. The reported study was funded by RFBR according to the research project No. 16-35-00494 mol_a and grant of the Government of the Russian Federation No. 14.Z50.31.0017. References: Le Goff, M., Gallet, Y., 2004. A new three-axis vibrating sample magnetometer for continuous high-temperature magnetization measurements: applications to paleo- and archeo-intensity determinations. Earth Planet. Sci. Lett. 229, 31e43 Thellier E., and O. Thellier, 1959. Sur l’intensite´ du champ magne´tique terrestre dans le passe´ historique et ge´ologique, Ann. Geophys., 15, 285–378. Coe, R.S., 1967. Paleointensities of the Earth’s magnetic field determined from tertiary and quaternary rocks. J. Geophys. Res. 72, 3247–3262
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EXTREMELY WEAK PALAEOINTENSITY RESULTS FROM THE MINUSA BASIN AND KOLA PENINSULA: WAS THE DEVONIAN FIELD SPATIALLY COMPLEX?
Shcherbakova V.V.1, Biggin A.2, Shatsillo A.V.3, Veselovskiy R.V.3,4, Hawkins L.2, Shcherbakov V.P.1,
Zhidkov G.V.1
1 - GO "Borok" IPE RAS 2 - University of Liverpool, UK
3 - Institute of the Physics of the Earth RAS 4 - Lomonosov Moscow State University
Defining variations in the behaviour of the geomagnetic field through geological time is critical to understanding the dynamics of Earth’s core and its response to mantle convection and planetary evolution. Furthermore, the question of whether the axial dipole dominance of the recent palaeomagnetic field persists through the whole of Earth’s history is fundamental to determining the reliability of palaeogeographic reconstructions and the efficacy of the magnetosphere in shielding Earth from solar wind radiation. Previous palaeomagnetic studies have suggested that the palaeofield had a complex configuration in the Devonian period (419-359 Ma). Here we present new palaeointensity determinations from rocks aged between 408 and 375 Ma from the Minusa Basin (southern Siberia), and the Kola Peninsula to investigate the strength of field during this enigmatic period. Palaeointensity experiments were performed using the thermal Thellier, microwave Thellier, and Wilson methods on 165 specimens from 25 sites. Six out of eight successful sites from the Minusa Basin and all four successful sites from the Kola Peninsula produced extremely low palaeointensities (< 10 µT). These findings challenge the uniformitarian view of the palaeomagnetic field: field intensities of nearly an order of magnitude lower than Neogene values (except during relatively rare geomagnetic excursions and reversals) together with the widespread appearance of strange VGP positions found in the Devonian suggest that the Earth’s field during this time may have had a dominantly multipolar geometry. A persistent, low intensity multipolar magnetic field and
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associated diminished magnetosphere would increase the impact of solar particles on the Earth’s magnetosphere, ionosphere and atmosphere with potential major implications for Earth’s climate and biosphere.
CAUSES OF FALSE PALEODIRECTION DETERMINATIONS OBTAINED ON SIBERIAN TRAP
AND STEENS MOUNTAIN ROCKS FROM CONVENTIONAL STEPWISE THERMAL
DEMAGNETIZATION
Shcherbakov V.P.1,2, Latyshev A.V.3,4, Veselovskiy R.V.3,4
1 - Geophysical Observatory Borok IFZ RAS 2 - Institute of Geology and Petroleum Technologies, Kazan
(Volga region) Federal University 3 - Schmidt Institute of Physics of the Earth
4 - Faculty of Geology, Lomonosov Moscow State University
The massive occurrence of reversed middle-temperature component was found during the standard stepwise thermal demagnetization of about 350 paleomagnetic samples of dolerites from Permian-Triassic Siberian intrusive bodies. At the same time, this reversed component was not detected during either AF cleaning or continuous thermal demagnetization. Results of experimental studies and numerical modeling prove that the reversed component is an artifact caused by presence of partly oxidized titanomagnetite grains with property of partial self-reversal of NRM. A generalization of this model for the case when a secondary component NRM2 is superimposed under a certain angle to the primary partial self-reversed component NRM1 provides a likely explanation to the striking difference in results of standard stepwise and rapid continuous thermal demagnetization of Steens Mountain rocks (Coe et al., 2014). It is shown that a presence of a partial self-reversed component of NRM in a sample may substantially deform results of conventional stepwise thermal demagnetization leading to wrong interpretation of paleodirectional analysis. Providing that titanomagnetite grains are often abundant in volcanic rocks, this situation seems to be not uncommon and in the case of
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uncertainty the application of continuous thermal demagnetization can solve the dilemma.
DETERMINATION OF HYSTERESIS LOOP PARAMETERS USING COMBINATION OF LINEAR
AND SPLINE INTERPOLATIONS
Solyanikov Ya.L., Malakhov M.I.
Shilo North-East Interdisciplinary Scientific Research Institute FEB RAS
The magnetic measurements are aimed to identify grain size, domain state and other properties of the magnetic minerals in samples. The RockMagPlot is a software to determine magnetic parameters from partial hysteresis loops in measurement files obtained from J meter coercivity spectrometer (available from https://github.com/yaroslav1982/RockMagPlot/). Despite the increased noise of hysteresis loops determined by J meter spectrometer compared with that by MicroMag 2900, it uses a robust design for measuring a geological samples magnetic hysteresis loop and IRM acquisition spectrum in 6 minutes (http://adsabs.harvard.edu/abs/2009AGUSMGP33A..01E). The RockMagPlot program combines the smooth curve characteristics of spline interpolation, with the non-overshooting behaviour of linear interpolation (this method is described at http://www.korf.co.uk/spline.pdf). With the help of numerical interpolation techniques, derivative of magnetic hysteresis loop can be obtained, and the program calculates the ferrimagnetic and paramagnetic contributions of hysteresis curve.
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HYDROMAGNETIC SOURCES OF FOUR CENTURIES OBSERVED MULTI-POLES IN THE EARTH’S CORE
Starchenko S.V., Yakovleva S.V.
Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation, Troitsk, Moscow, Russia
Using IGRF (1900-2015) and gufm1 (1590-1990) geomagnetic models we roughly evaluated direct hydromagnetic sources of Gauss components corresponding to magnetic multi-poles. To do so we obtained the logarithmic time derivatives of those components each 5 years. The derivatives’ values determine the hydromagnetic sources those are about the driving velocity gradients. More precisely each source is equal to correspondently averaged ratio of generation-dissipation term to component value. This is described by approximate mean-field equations those we obtained expanding the magnetic induction equation in term of Gaussian-type spherical harmonics. We argue that the obtained hydromagnetic sources are dependent mainly on higher degree expansion components those are hardly observable, while we, perhaps for the first time, evaluated their average physical properties. Among those properties we in original form investigated their generation-dissipation spectra, periodicities and amplitudes allowing us to estimate various geomagnetic and geodynamo parameters from the direct observations.
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DEDUCING GEODYNAMO AND PLANETARY DYNAMO PARAMETERS FROM SCALING LAWS, DIRECT OBSERVATIONS AND PALEOMAGNETIC
RECONSTRUCTIONS
Starchenko S.V.
IZMIRAN
Basing on currently defined conductivity, 115 years observed evolution of the geomagnetic dipole, Faraday's and Ohm's laws I estimate averaged radial derivatives of the vortex magnetic field hidden just below the surface of the Earth's core. This allows to formulate a simple model of vortex field beneath the surface of the core and to evaluate typical scale of the field, which determines the major geodynamo parameters and the adequacy range of the proposed simple model. Estimated scale of the vortex field (about 60 km) is much less than the typical scale resulting from the extrapolation of the observed field to the core-mantle boundary. This agrees well with the modern planetary dynamo theory, allowing direct observational estimation of the typical velocity field just beneath the surface of the Earth’s core. The proposed new approach to determine the subsurface characteristics of the hidden in the depths of the physical object of the vortex magnetic field and velocity from the observed evolution of the potential field can be used for both astrophysical and for technical objects with hardly accessible electric current systems. Scaling laws for MHD dynamo in fast rotating planets express the characteristic energy, hydrodynamic and magnetic values through the primary values, such as the size of the conductive core of the planet, the angular rotation rate, electrical conductivity and energy flows. Most of the earlier proposed scaling laws based only on observations and assumptions about force balances. Recent and my new approaches to fully take into account the energy and induction balance has additionally expressed here in terms of primary values such important characteristics as forces, magnitudes, energies, scales and orientations of hydromagnetic fields. The direct numerical simulation of the dynamos and modeling ability in a fairly wide range of parameters for the first time allowed direct test such laws.
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The obtained numerical geodynamo-like results for the Earth, Jupiter and partially Saturn postulated previously not identified analytically simplest law that predicts the field strength is only depended on the specific energy density of convection. This already widely used law was original way analytically grounded here along with other previously known and new laws. This analytic identifies the physics determining geomagnetic periodicities for jerk, secular variations and inversions/excursions. Mean period between the inversions is roughly proportional to the intensity of the geomagnetic field that is confirmed by some paleomagnetic researches. Possible dynamos in Mercury, Ganymede, Uranus and Neptune are also discussed. This work was partly supported by Russian RFBR grant No 16-05-00507.
MAGNETIC PROPERTIES OF IMPACT MELTS FROM THE ZHAMANSHIN ASTROBLEME REFLECTING THEIR FORMATION IN EXTREME CONDITIONS
Starunov V.A.1, Kosterov V.A.2, Sergienko E.S.2, Kharitonskii P.V.2
1 - St. Petersburg Branch of Institute of Terrestrial Magnetism, Ionosphere and Radio Wave Propagation of Russian Academy
of Sciences 2 - St. Petersburg State University
The object of this study were polymineral glasses of shock-explosive genesis collected on the surface of the Zhamanshin meteorite crater, Kazakhstan (48°24'N, 60°48'E, diameter 13 km, age about 1 Ma). Impact glasses locally called zhamanshinite occur as bombs, lapilli, "spills" formed of massive glass, slags, pumice up to 0.5 m across. Zhamanshinites are products of cooling of impact melt, whose maximum temperature could locally have been up to 2500-3000°C and initial cooling rate up to 200°C/s [1]. Extreme formation conditions of zhamanshinites cause the occurrence in them of fine ferrimagnetic particles in the superparamagnetic (SP) state. Identification of SP particles supposed to co-exist with stable single-
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domain (SD) and multidomain (MD) grains was carrie out using a set of the domain structure (DS) criteria, including the following: coercivity ratio Hcr/Hc; factor F'= Mrs/(χARM·Hcr), where Mrs is saturation remanent magnetization, and χARM is susceptibility of anhysteretic remanent magnetization; parameter (ΔMr/ΔM)max – the maximum value of the ratio of coercive spectra of isothermal remanent magnetization Mr and total in-field magnetization M reached in a magnetic field Hc
max. We also determined the magnetic viscosity and the decline of magnetization Mr with time. According to the DS parameters and the results of thermomagnetic analysis all studied samples can be arranged in a continuous series, the extreme members of which are respectively acidic zhamanshinites containing mostly SP particles of variable composition titanomagnetite with Curie temperatures Tc ≤ 400°C (Hcr/Hr = 50-66, (ΔMr/ΔM)max = 0.01, Hc
max = 100-120 mT) and the samples containing predominantly MD grains of low-Ti titanomagnetite with Tc = 500-550°C (Hcr/Hr = 2-4, (ΔMr/ΔM)max = 0.15-0.39, Hc
max = 12-20 mT; F'= 0.5-0.8). Conclusions: 1. SP particles can be detected in nearly all samples, and in the majority of the acidic glasses an SP-phase dominates the magnetic responce. 2. Differences in the domain structure and composition of zhamanshinite ferrimagnetic phase result from different initial temperatures of the impact melt from which zhamanshinites were formed. Samples containing mostly SP particles are formed from the superheated melt at extremely high cooling rate. BIBLIOGRAPHY Feldman V.I., Sazonova L.V. Conditions of formation and solidification of impact melts in Zhamanshin astrobleme, Petrology, 1993, 1(6) 596 - 614 (in Russian).
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POSSIBILITIES OF PEAT FOR DIAGNOSTICS OF THE NATURE OF CATASTROPHE EVENTS ACCORDING
TO MAGNETIC AND MICROPROBE DATA
Tselmovich V.A.1, Kurazhkovskii A.Yu.1, Kazansky A.Yu.2, Shchetnikov A.A.3, Blyakharchuk T.A.4, Amelin I.I.4,5
1 - GO "Borok" of IFZ RAS 2 - MSU
3 - IZK of the Siberian Branch of the RAS 4 - IMKES of the Siberian Branch of the RAS
5 - IVMIMG Siberian Branch of the RAS
Peat has an opportunity to accumulate information on dynamics of the ecological conditions taking place in the course of peat accumulation in the layers. In layers of peat information about cyclic and about short-term catastrophic events which influence a condition of an ecosystem is saved. Measurement of physical properties of the samples of peat which are selected on the power of the formed thickness allows to carry out reconstruction of physical conditions in which the studied deposits were formed. To one of the parameters characterizing peat accumulation conditions can serve magnetization of saturation of samples of peat. So, measurements of magnetization of saturation (Irs) and density of samples of peat allow to make the conclusion about a ratio of organic and mineral substance. We have studied changes of Irs of the samples which are selected on the power (core length) the peat two Holocene of deposits. The coal mine 1 has been selected from the drained callus (a riding bog) on the delta of river. Selenga (Buryatia) near the Ambassadorial station, coordinate 52 ° 0'32.29 "C 106 °22'21.08" V.) . 306 samples are studied. The second section - a bog "Tundra" the Kemerovo region, Mezhdurechensk area, mountains Kuznetsk Alatau. This sfagnovy bog "Tundra" is located in a flood plain of river. A mustache upstream from Mezhdurechensk. Samples have been taken from a river exposure of a peat bog in a point with coordinates 54,78649º to NL, 88,27233º EL, height above sea level of 273 m. The opened power of a peat bog of 260 cm schedules of dependence of Irs on section depth Have been constructed. On schedules both high Irs
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values (peaks), and minima of Irs values were visible (failures). By means of a microprobe samples from the horizons, both with minimum, and with the maximum Irs values have been studied. It has been shown that zones with the minimum values contain particles of a background fossil cosmic dust. Perhaps, these zones have arisen in the course of a cold snap. In a zone with high values, excepting the first zone with anthropogenous pollutants, minerals of a space origin are noted. Possibly, they testify about the impact events which age will be defined later.
AEROMAGNETIC SURVEYS USING UNMANNED AERIAL VEHICLES IN FOREIGN COUNTRIES AND
IN RUSSIA
Tsirel V.S., Semenova M.P., Titova A.V.
The Federal State Unitary Research and Production Enterprise «Geologorazvedka», Saint-Petersburg, Russia
1. Problem of using Unmanned Aerial Vehicles (UAV) for geophysical surveys started in 1995 - publications in Australia and the USSR. However, first experiments at the end of the XX century (Australia ) and at the beginning of the XXI (Canada ) proved unsuccessful in spite of the obvious merits of the new technology, first of all - there is no risk of human loss and no necessity of using high cost airfields, to say nothing of its ecological merits etc. 2. At present it is possible to register the formation of a modern technique- technological base of unmanned aeromagnetics. It was started by the Canadian firm "Sander Geophysics" using a special kind of UAV "GeoSurv II". 3. Canadian firms and firms of other countries have effectuated different kinds of aeromagnetic surveys in different regions of the globe differing in purpose and volume. The main type of carrier is UAV, a plane which can be triggered by a catapult or use a runway. Kinds of surveys are either a module survey with a one sensor equipment or gradient survey with a two-sensor equipment (sensors are placed at the ends of wings).
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4. Experimental surveys in Russia are at present effectuated only by the Vernadsky State Geological Museum, Russian Academy of Sciences using a UAV A-301 (created by the firm «Geoscan») . Further research is going on in Saint- Petersburg, Irkutsk and Novosibirsk. 5. In the future we affirm that the use of unmanned aeromagnetics for studying magnetic properties of rocks for discovering many kinds of solid economic minerals as well as for a detailed study of platform structures with promise for hydrocarbons, will be widely used.
WHEN SEDIMENTS FAIL TO RECORD GEOMAGNETIC FEATURES
Valet J.P.1, Meynadier L.1, Simon Q.2, Thouveny N.2
1 - Institut de Physique du Globe de Paris, France 2 - Cerege, Aix en Provence, France
The importance of sedimentary records for studies of geomagnetic field behavior is not questioned, but the limits of their signal remain unclear and a matter of discussion. We have compared and four distinct records of the last reversal from different locations and deposition rates of the order of 4 cm/ ka, i.e. with the resolution of most records from the database and have been extensively used for reversal models. In three records stepwise demagnetization of the transitional samples revealed a succession of scattered directions instead of a well-defined characteristic component of magnetization. This behavior could be caused by weakly magnetized sediment. However the transitional samples of two cores have almost three orders of magnitude stronger magnetizations than the non-transitional samples that yielded unambiguous primary directions in the other two cores. Therefore the weakness of the field might not be only responsible and it is likely that the rapidly moving non-dipole components generated different directions that were recorded over the 2 cm stratigraphic thickness of each sample. We infer that sediments with this resolution do not properly document other features than those of the axial dipole field. Consequently, more than 95% of the reversal records and in turn the models derived from sedimentary records should somehow be put in question. We will also discuss records of relative paleointensity by comparing the amplitude of the
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changes in 10Be production with those of relative paleointensity at each site.
NEW PALEOMAGNETIC DATA FROM THE EMEISHAN TRAPS AND PANZHIHUA LAYERED
INTRUSION, SW CHINA
Veselovskiy R.V.1,2, Krivolutskaya N.A.3,1, Song X.-Y.4, Chen L.-M.4, Yu S.-Y.4, Smolkin V.F.5, Gongalskiy B.I.6
1 - Lomonosov Moscow State University 2 - Institute of Physics of the Earth RAS
3 - Vernadsky Geochemistry Institute RAS 4 - Institute of Geochemistry, Chinese Academy of Sciences
5 - Vernadsky State Geological Museum 6 - Institute of Geology of Ore Deposits, Petrography,
Mineralogy, and Geochemistry RAS
We present new paleomagnetic data from the Late Paleozoic Emeishan Traps sections (Ertan and Bingchuan areas) and Panzhihua layered intrusion (SW China) and make the first preliminary conclusions about correlation of intrusive and effusive magmatism in the time. Moreover, we use obtained paleomag data to estimate the bedding of studied lava sections and give some methodological recommendations for the future detailed paleomagnetic studies of these objects. This study was funded by grants 15-35-20599 (RFBR) and the Project “Sources, composition and condition of the Fe-Ti-V and Cu-Ni deposit in layered intrusion related to crystallization of basic-ultrabasic magma”.
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NEW MIDDLE-LATE DEVONIAN PALEOMAGNETIC POLE FOR EAST EUROPEAN PLATFORM AND
AR/AR AGES FROM THE KOLA ALKALINE MAGMATIC PROVINCE
Veselovskiy R.V.1,2, Kulakova E.P.1
1 - Lomonosov Moscow State University 2 - Institute of Physics of the Earth RAS
We present new paleomagnetic data and Ar/Ar ages from the Kola Devonian alkaline magmatic province. New paleomagnetic pole for East European platform was calculated based on paleomag data from 32 dolerite and alkaline dykes and intrusive massifs. Eight of these intrusions were dated by Ar/Ar method. We also discuss the question about duration and dynamics of Devonian intrusive magmatism on Kola Peninsula, correlation between its tholeiitic and alkaline phases and point out the problems and goals arise before future paleomag and geochoronological studies of the Kola Devonian magmatism. This study was funded by grants 15-35-20599 (RFBR) and 14.Z50.31.0017 of the Government of the Russian Federation.
THE LATE ORDOVICIAN-SILURIAN REVERSAL DEPOSITS OF THE WESTERN SLOPE OF THE
SOUTHERN URALS
Vinogradov E.V.
Novosibirsk State University
Ordovician-Silurian carbonate-terrigenous sedimentary rocks of the Western- Zilair area of the Urals have been proven a reliable recorder of
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paleomagnetic signal. Dolomitic and quartz sandstones that belong to the nabiulino, uzyan, and sermenevo formations, sampled from Kurgashly (3 sites, 31 sample), Kaga - Verh. Avzyan (3 sites, 21 sample), and Sermenevo (2 sites, 21 sample) sections have been studied paleomagnetically. Stepwise thermal and alternating field (AF) demagnetizations reveal two-component natural remanent magnetization (NRM) in studied samples. A viscous NRM component, associated with the present-day geomagnetic field is removed by heating to 280°C or AF of up to 10 mT. A stable characteristic NRM component is isolated between 300 and 580°C or 20-120 mT. This component is characterized by a negative inclination in all studied samples. The site-mean paleomagnetic directions of the characteristic remanence, have the best clustering in geographic coordinates (i.e. before the correction for structural tilt). The maximum K-statistics (Kmax=110,7) is achieved at 8% of unfolding, indicating a post-folding age of magnetization. The corresponding paleomagnetic pole, calculated assuming the reversed polarity of geomagnetic field, is located at 46.7° N 177° E, with 95% confidence radius A95=6.2°. The pole is close to the Late Paleozoic segment of Baltica APWP. The age of the magnetization corresponds to the main stage of tectonic deformations of Urals at ~ 300 Ma. Based on available data, remagnetization processes affected not only the early Paleozoic sedimentary rocks of Zilair zone studied in this work, but the entire western part of the Southern Urals, including Devonian-Early Carboniferous deposits. Thus, the observed Late Paleozoic remagnetization has a pervasive regional extend and likely reflects a collision event associated with the final stage of the Ural paleoocean. The work was supported by the Ministry of Education of the Russian Federation (project №5.515.2014 / K).
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PALEOMAGNETISM OF THE EARLY PROTEROZOIC COMPLEXES OF THE OLEKMA BLOCK OF THE
SIBERIAN CRATON
Vodovozov V.Yu.1,2, Zverev A.R.2, Filev E.A.1
1 - Moscow State University 2 - Geological Institute, Russian Academy of Sciences
The report presents the results of a 5-year study of the Early Proterozoic complexes of the Olekma block of the Aldan province of the Siberian craton. The main objects were chosen approximately coeval postcollision complexes: granite massifs of the kodar complex with ages of 1873+/-3 Ma and 1877+/-4 Ma, gabbroids of China (1867+/-3 Ma) and Kuranakh complexes (1863+/-9 Ma). In the four studied granite massifs of the Kodar complex found rocks suitable for paleomagnetic study. The primary of high-temperature components NRM is confirmed by positive reversal tests and coincidence of components in remote massifs. The mean paleomagnetic pole is Plat=-22.9° Plong=98.9° A95=7.9°. Samples gabbro of the China complex were selected in the central part China massif and several dikes near the massif. Dedicated high-temperature characteristic components on a stereogram form a cluster in the northeast, there are a few samples from the antipodal components. The mean paleomagnetic pole: Plat=-19.1° Plong=87.4° dp/dm=4.8/9.3. The most easterly object was Kuranakh complex. Samples were selected from 4 dykes of the gabbro-diabase. Obtained high-temperature components of NRM are antipodal China and Kodar complexes. There are also reverse polarity samples. The contact test with metasandstones of the Atbastakh suite is positive. Mean paleomagnetic pole is almost identical with the pole of the Kodar granites: Plat=-22.7° Plong=102.3° dp/dm=5.6/10.9. Mean paleomagnetic pole for 3 complexes is Plat=-21.7° Plong=96.1° A95=11.6°. This pole falls like was expected in begin of the Early Proterozoic APWP Siberia (Didenko et al., 2015). With the introduction of
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the correction by the opening Vilyui rift by hypothesis (Pavlov et al., 2008) it is shifting towards younger poles, allowing a few to doubt this hypothesis with regard to Olekma block. Comparing the data obtained with the known the Early Proterozoic poles of the south Siberia, one can conclude that the rigidity of the craton starting around 1.86 Ga.
EVALUATION OF GEODYNAMO PARAMETERS AND OLDER FIELDS FROM DIPOLE AND QUADRUPOLE
OBSERVED SINCE 1840
Yakovleva S.V.1, Starchenko S.V.1, Ivanov V.V2
1 - Pushkov Institute of terrestrial magnetism, ionosphere and radio wave propagation, Troitsk, Moscow, Russia
2 - Federal state budgetary educational institution of the high professional training Azovo-Chernomorskaja state
agroengineering academy, Zernograd, Russia
We estimate the generation mechanisms using the known geomagnetic surface field models, SOMPI method, our asymptotic large-scale kinematic geodynamo-like solutions and original description of harmonic magneto-convective sources of the main geomagnetic field in the Earth's core. The description is based on a complete system of eigenfunctions of the magnetic diffusion equation in a homogeneously conducting sphere surrounded by an insulator. Thus, the electric current sources of the main geomagnetic field are estimated by smooth functions. Our dipole sources are directly related to the observed geomagnetic dipole, whereas quadrupole sources are related to the quadrupole, etc. Our main date source is gufm1 model restricted by 1840-2010 period because prior to AD1840 the available historical core field models rely on directional observations only without any intensity observation. The restricted gufm1 model was used for identification of the large-scale geomagnetic sources by SOMPI method. This auto-regression method is able to define the harmonic periods of order or even larger than the initial time interval. So, we were easy able to extend our geomagnetic model up to AD1700. We compare our forecast with the available long-time models
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drawing the conclusion that even the best gufm1 model is not so correct during 1700-1840. It was revealed that the main harmonic source of the axial dipole is approximated by three-dimensional ring of electric current flowing around the axis of rotation of the Earth and several times changing its direction. The modern axial geomagnetic dipole has diffusion component only that decreases for ten times during about 2500 yrs. This determines the minimum period that can separate us from the commencement of further inversion or excursion. The equatorial dipole and all quadrupoles have drift, generating and diffusion components with different periods and amplitudes. These results allow us to estimate dipole/quadrupole generation/attenuation effects and the Earth’s core conductivity.
PALAEOINTENSITY DETERMINATIONS ON ROCKS FROM PALEOPROTEROZOIC DYKES FROM THE
KOLA PENINSULA (RUSSIA)
Zhidkov G.V.1, Shcherbakova V.V.1, Lubnina N.V.2, Shcherbakov V.P.1, Smirnov M.A.1
1 - GO "Borok" IPE RAS 2 - Lomonosov Moscow State University
Twelve high quality paleointensity determinations on dyke from the Late Archaean/Early Proterozoic boundary (Karelia, Russia) of 2.505 Ga age are obtained yielding very strong average VDM (12-14)×1022 Am2 (without the cooling correction). Electron microscopic studies have shown that magnetite grains – carriers of NRM – in these samples are encapsulated in silicate grains, what make them less susceptible to chemical and structural alterations providing a possibility for a reliable record of geomagnetic field intensity. Summarizing all data available in the World Paleointensity databases, we can affirm the domination of strong dipolar field around the Archaean/Proterozoic boundary at the time interval 2.4–2.8 Ga.
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EARLY PROTEROZOIC NRM COMPONENTS OF AKITKAN GROUP OF MINYA RIVER - NEW TWO
PALEOMGNETIC POLES
Zverev A.R.1, Vodovozov V.U.1,2
1 - GIN RAS 2 - MSU
This report presents the final results obtained from paleomagnetic studies of the Early Proterozoic rocks of Akitkan Group of south of the Siberian craton (Minya river). The main objective of these studies was to clarify and supplement of Palaeoproterozoic APWP of Siberia in the range of 1880-1750 million years. Minya river slots Ridge Akitkan within postcollisional North Baikal volcano-plutonic belt. During two field seasons it has been selected 407 samples of volcanic-sedimentary and volcanic rocks of chayskya hibelenskya suites of 34 points. The samples were subjected to a complete cleaning of the temperature in the laboratory of petromagnetic of MSU and paleomagnetic laboratory of Geological Sciences. There are two statistically differing components in the high range in the diagrams of Zijderveld. The first component (ht1) on a stereogram is located in the third quarter, there are also some reverse polarity samples. Fold test positive for it. The second component (ht2) has a bipolar distribution and located in the second and fourth quarters of stereogram. Treatment test positive components, fold test indefinitely. Both components can occur at one site, or even in the same sample (siltstone). Calculated on both components of the poles hit the Early Proterozoic APWP of Siberia (Didenko et al., 2015). The first pole (ht1 component, Plat = -24.3 Plong = 94.3 dp / dm = 2.9 / 5.7) is almost identical with the pole of chayskya suites on the river Chaya, which has the age of 1863 +/- 9 million years. As rocks containing component ht1, in IGGD RAS was obtained isotopic age dating of the U / Pb zircon isochron method - 1879 +/- 15 million years (AB Kotov, l / s). The second pole (ht2 component, Plat = -25.3 Plong = 136.2 dp / dm = 8.5 / 16.9) is biased towards the rejuvenation of paleomagnetic poles. The volcanics, which stands out is the
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direction was received earlier dating of estimating the age of rocks as a 1823 +/- 7 million years (Neumark et al., 1991). A similar picture can be explained by the formation of two phases of chayskya suite on Minya river. The first phase corresponds to the time of formation Formation (1863-1873 million years), the second phase is associated with the introduction of Minys paleovolcano time and meets approximately 1823 million years. These poles are significantly reinforce the Early Proterozoic APWP of Siberia.
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EG. EXPLORATION GEOPHYSICS AND EARTH CONDUCTIVITY
COMPARISION OF THE AMPLITUDE AND THE PHASE GEOELECTRICAL MODELS OF THE MT
PROFILES IN BELARUS
Astapenko V.
Republican Unitary Enterprise "Research and Production Center for Geology", Minsk, Belarus
A series of magnetotelluric sounding have been carried out across three profiles in Belarus. On great part of territory of Belarus have been observed zones of crustal anomalies of electrical conductivity. We cannot reliably estimate the depth to the top of the layer and its electrical parameters without correcting the shape and level of the amplitude curves MT sounding exposed to galvanic distortions. Now we presents the results of joint interpretation of the phase and amplitude curves MT soundings. The new geoelectrical models of lithosphere were permit making more precise the value of the conductivity and the depth of anomalous layers.
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PROSPECTS OF USING THE NUMERICAL MODELLING IN CONJUNCTION WITH THE
GROUND PENETRATING RADAR (GPR) TO STUDY ICE WEDGES
Bricheva S.S.1, Stanilovskaya Ju.V.2
1 - Lomonosov MSU, Faculty of Geology, Seismics and Geoacoustics Department
2 - Sergeev Institute of Environmental Geoscience of the Russian Academy of Sciences (IEG RAS)
Permafrost environments cover a fifth of the land area: 60% of Russia, 25% of China, 80% of Alaska and about 50% of Canada. The permafrost studies often take place in hard conditions − in wetlands and in impassable areas like taiga with dense vegetation cover. Permafrost structure is very sensitive to various mechanical and thermal influences. Consequently, permafrost geophysical methods should be non-invasive, possibly remote and quick. The ground penetrating radar (GPR) is promising in such conditions. The high dielectric contrast between ice and water determines the possibility of identifying the boundaries between melt and frozen grounds on the GPR data (radargrams), as well as local objects such as ice wedges. In August 2015 we carried out the fieldwork in the Chara Depression (Zabaykalsky Krai, Eastern Siberia, Russia). Modern and relict ice wedges were observed in almost all parts of the relief. We used GPR to detect ice wedges with invisible polygons, which was seen in the river outcrop. We wanted not only to determine the location of ice wedges, but also its shapes and sizes without drilling. This information is essential for thermokarst risk assessment, for paleogeographic studies, for the estimation of the amount of buried ice, etc. The geological section of fieldwork site was represented by frozen sandy loam covered with peat in the active layer. We used GPR system ZOND-12e (Radar Systems Inc., Latvia) with shielded 300 MHz antenna. The study was conducted using the funds of RFBR “My first grant” №14–05–31510. An integral part of the study was numerical modelling in the free software tool gprMax (http://www.gprmax.com). We made several models of
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subsurface based on photographs of outcrop, where the GPR survey was conducted. The comparison of real and simulated data is found to be extremely useful to interpret field data and understand the location and the size of ice within the permafrost. We analyzed also the influence of different factors, like shape of ice wedge, permafrost table boundary and deposit conductivity, on synthetic radargrams. Here, we present both field and modelling results.
COMPLEX ALGORITHM FOR NEURAL NETWORK SOLUTION OF THE INVERSE PROBLEM OF
MAGNETOTELLURIC SOUNDING BASED ON DATA CLASSIFICATION
Dolenko S.A.1, Isaev I.V.1, Obornev I.E.1,2, Obornev E.A.2, Shimelevich M.I.2
1 - D.V.Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University, Moscow, Russia
2 - S.Ordjonikidze Russian State Geological Prospecting University, Moscow, Russia
Solution of the inverse problem (IP) of magnetotelluric sounding (MTS) is the process of construction of an operator mapping the vector of components of electromagnetic fields induced by nature sources, measured on the Earth’s surface, to the distribution of electrical conductivity in the studied underground area. This IP is a complicated high-dimensional ill-posed problem with a well-known instability. To describe the sought distribution of the electrical conductivity, different parameterization schemes are used. The most general scheme G0 uses the values of conductivity in the nodes of a pre-defined grid, with further interpolation between nodes. More specific schemes may assume presence of one or several conducting or insulating layers with variable thickness and conductivity, on the top of the area of general parameterization. Transfer from the solution of the IP within scheme G0 to its much more stable solution within one of specific schemes in a narrower class of geoelectric sections causes the necessity of prior classification of the
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studied data pattern, resulting in the selection of the most appropriate parameterization scheme to apply the IP solution. In their previous studies, the authors demonstrated that using perceptron type artificial neural networks (ANN) provides solution of the MTS IP with an acceptable error, especially if simultaneous determination of a group of several parameters is used, for any parameterization scheme. The described classification problem can be also successfully solved by ANN. In this study, the complex algorithm combining classification with subsequent IP solution with ANN within partial classes of geoelectric sections, is approbated against the single-stage general approach within the most general parameterization scheme G0. The results are analyzed, and the recommended algorithm of MTS IP solution is discussed. This study has been performed at the expense of the grant of Russian Science Foundation (project no.14-11-00579).
ON THE CONVECTION WITHIN THE MANTLE WEDGE BENEATH THE TIMAN-PECHORA PLATE AS
A MECHANISM OF TRANSPORT OF HYDROCARBONS AT PALEOZOIC
Gavrilov S.V.1, Kharitonov A.L.2
1 - The laboratory 102 of the Schmidt Institute of Physics of the Earth of the Russian Academy of Sciences, 142190, Russia,
Moscow 2 - The Pushkov Institute of Terrestrial Magnetism, Ionosphere
and Radio Wave Propagation of the Russian Academy of Sciences, 142190, Russia, Moscow
Topography depressions and uplifts on the Timan-Pechora lithospheric plate alternate quasi periodically and are nearly parallel to the South-Western border of the plate. This probably is indicative of the convective origin of topography spatial undulations, the convection at the mantle wedge being due to the subduction of the East-European plate under the Timan-Pechora one in the course of closing of the former Urals ocean at Paleozoic. The oil- and gas-bearing provinces are associated with the relief
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uplifts, what probably can as well be due to the Paleozoic upward convective transport of the mantle hydrocarbons. Numerical mantle thermal convection modeling accounting for the temperature and pressure dependence of the “wet” olivine viscosity shows the characteristic convective rolls scale is approximately the same as the spatial wavelength of localization of the oil- and gas-bearing zones at the Timan-Pechora region if convection is assumed to be driven by the dissipative heating in the mantle wedge. The scale of the oil- and gas-bearing zones localization periodicity is approximately equal to convection cell dimensions which may serve an additional evidence for convective mechanism of non-organic hydrocarbons transport to the Earth’s surface.
APPLICATION OF CLASSIFICATION ALGORITHMS FOR SELECTION OF THE OPTIMAL
PARAMETRIZATION SHEME IN THE INVERSE PROBLEM OF MAGNETOTELLURIC SOUNDING
Isaev I.V.1, Obornev I.E.1,2, Obornev E.A.2, Shimelevich M.I.2, Dolenko S.A.1
1 - D.V.Skobeltsyn Institute of Nuclear Physics, M.V.Lomonosov Moscow State University, Moscow, Russia
2 - S.Ordjonikidze Russian State Geological Prospecting University, Moscow, Russia
The inverse problem of magnetotelluric sounding (MTS IP) is the problem of reconstruction of the distribution of electrical conductivity in the thickness of the earth by the values of the components of electromagnetic fields measured at its surface This IP is a non-linear ill-posed ill-conditioned problem with high dimensionality both by input and by output. The traditional method of solving such problems is the method of residual minimization, based on repeated solution of the direct problem. This determines the inherent shortcomings of this method: high computational cost, low operation speed, necessity of pointing out the first approximation; when this method is used, the role of an expert is high. One of the methods free of many shortcomings inherent for traditional methods of IP solving, is
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the use of artificial neural networks (ANN). For realization of the neural network solution the sought-for distribution has to be defined by a finite number of parameters by introducing a so-called parameterization scheme. In the most general scheme G0 the distribution of conductivity is described by its values in the nodes of the macro-grid, and the conductivity values among the nodes are calculated by interpolation. But a much more stable and well-posed solution can be implemented by using a specific parameterization scheme, containing some geological features. In particular, in this paper we consider the schemes, containing one or several conducting or insulating layers with variable thickness and conductivity, on the top of the area of general parameterization. Selecting the appropriate parameterization scheme requires solving the problem of multi-class classification, which is the goal of the present study. In this study, various classification algorithms were considered and compared, and their optimal parameters were found. Maximum possible classification accuracy and minimum size of the training set were estimated. Also all algorithms were tested for resilience to noise in data. This study has been performed at the expense of the grant of Russian Science Foundation (project no.14-11-00579).
SPECTRAL ANALYSIS OF THE GEOBIOCHRONOLOGICAL CYCLES SHOWN IN THE
COURSE OF EVOLUTION OF THE EARTH AND THEIR COMMUNICATION WITH PHYSICAL FIELDS
OF SPACE
Kharitonov A.L.
Pushkov Institute of Terrestrial Magnetism, Ionosphere and Radio waves propagation of the Russian Academy of Sciences, 142190,
Russia, Moscow
Carried out the analysis of influence of space fields on global periodic changes of natural processes on Earth and as a result on nature of periodic climatic and biological changes (global epidemics of a biota, climatic
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cataclysms) during its evolutionary development. As basic experimental data various series of geophysical and biological data for the last 3700 m.y. were used. Data were analyzed by a spectral method of the maximum entropy. As a result of the spectral analysis some main frequency which were divided by authors into some categories were marked out: the megacycles with a range of frequency from 13 to 920 m.y. corresponding to Shtrek's megacycles (740±180 m.y.), to Vilson's (370±90 m.y.), to Bertrán's (185±45 m.y.), to Sorokhtin (60±15 m.y.), to Stille's (23±10 m.y.); biooceanic trasgressionny makrocycles (3±1 m.y.); climate-biological microcycles of Milankovich (T = 21, 41, 90 thousand years); nanocycles with a range of frequency of half a year to several thousand years such as: solar&magnetic&biological nanocycle of Golovkov-Vitinsky (600±160 years), a solar&biological nanocycle (176±48 year), a solar-biological nanocycle (132±36 year), a "century" solar-biological nanocycle (88±24 years), a solar-biological nanocycle of Kondratyev (66±18 years), a temperature-biological nanocycle (44±12 years), solar&inversion and climatic-biological nanocycles of Vernardsky (22±6 year), of Chizhevsky (11±3 years), a geomagnetic nanocycle (6±2 years), geo&bio&climatic nanocycles with the periods: annual (1±0.25 year), semi-annual nanocycles (0.5±0.1 years), the nanocycles of Takata (1/12±0.02 years) which are shown in various geophysical and biological processes. By results of the analysis of the marked-out frequency in various geophysical and biological data the possible model of cause and effect biological-geophysical changes was formulated.
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MULTI-ELECTRODE ELECTRICAL PROFILING CARRIED ON UNDER THE LADOGA ELECTRICAL
CONDUCTIVITY ANOMALY IN COMPLEX WITH MT-AMT SOUNDINGS ("LADOGA-2015" EXPERIMENT)
Kolesnikov V.E.1, Zhamaletdinov A.A.1, Shevtsov A.N.1, Skorokhodov A.A.1, Ryazantsev P.A.2, Nilov M.Yu.2
1 - Geological Institute of KSC RAS 2 - Institute of Geology of KarSC RAS
The Ladoga electrical conductivity anomaly was discovered for the first time by I.I. Rokityansky (NAS of Ukraine, Kyiv) in 1970s. Its nature was explained by existence of fluids at a depth of 10 km. Further the anomaly was investigated by A.A. Kovtun and her team (SPbSU) using the AMT soundings. The anomaly has the 100 km width and includes three main conductive centers at the depth of 5-10 km, and it is traced to 40-60 km totally. Its longitudinal conductivity is about 2000 S. A main part of our investigations in 2015 was completed by DC resistivity profiling using the multi-electrode arrays of techniques (methods) of external sliding dipole (MESD) and internal sliding contact (MISC). In addition separate MT-AMT soundings were conducted. The MESD profiling was carried on along the roads of north-west coast of Ladoga lake as a continuous profile that was stricken across the anomaly. The length of the profile is 110 km, the step is 500 m. The MESD also included the soundings by 4 km step at the depth of about 500 m. Detailed investigations by the MISC were conducted at the sites of abnormal low apparent resistivity values detected by the MESD. A group of conductive zones was detected as a result of the investigations. The widths of the zones are in a range from tens of meters to several kilometers. The zones are bedded under moraine sediments or outcrop to earth-air surface. Extremely low values of apparent resistivity (sometimes it was several ohm-meters) indicate that the nature of the anomaly is connected with existence of sulphide and carbon contained rocks. The main zone location coincides the anomaly that was established by I.I. Rokityansky by the method of magnetic variation profiling (Rokityansky et
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al., 1979). The results of the "Ladoga-2015" experiment allowed to get a new look to the nature and structure of the Ladoga electrical conductivity anomaly as an object connected with definite geological structures that are bedded under moraine sediments or outcrop to earth-air surface.
MEASUREMENTS OF ELECTRICAL PROPERTIES OF ROCKS WITHIN A WIDE FREQUENCY RANGE
USING A FOUR-ELECTRODE SYSTEM
Linok A.V.
Saint Petersburg University
Vertical electrical sounding is a geophysical method for investigation of a geological medium. It is based on the estimation of electrical conductivity or resistivity of the medium. The estimation is based on the measurement of voltage of electrical field induced by the distant grounded electrodes. In this work we focus on electrical properties of rocks measured by four-electrode system. Measuring probe is of Wenner configuration. Figure 1 shows the configuration of the measurement setup. Electrodes A and B are current electrodes which are connected to a current source; N and M are potential electrodes which are used for the voltage measurements. As source, the direct current or low frequency alternating current is used.
Figure 1. Electrical profiling using four-electrode probes in Wenner configuration.
The interpretation of the measurements can be performed based on the apparent resistivity values. The depth of investigation depends on the distance between the current electrodes. The apparent resistivity is calculated as
where, k is a geometric factor, — voltage between electrodes М and N, — current in the line AB. The geometric factor is defined as
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, where aAM is the distance between electrodes. Water tests showed us that measuring probe satisfactory operates in the range from 1 Hz to 100 KHz. Calculation of electric parameters with parasitic capacity helps us to extend frequency range up to 1 MHz. Properties of sand from Sabetta port (Yamal peninsula) are defined in this work. Sand samples with different moisture content are investigated. Our investigation provides interpretation of geophysical data in Sabetta port.
DEEP STRUCTURE OF TOLBACHIK FISSURE ERUPTION BY MT SOUNDING
Moroz Yu.F., Loginov V.A.
The Institute of Volcanology and Seismology FEB RAS, Petropavlovsk-Kamchatsky, Russia
The article describes the method and results of the magnetotelluric sounding of AMT and MT modifications. Audiomagnetotelluric soundings (AMTS) was carried out for the first time in the area of modern volcanic eruption of Tolbachik volcano. Results of magnetotelluric parameter analysis indicate that geoelectric environment caused by the regional fault, can be approximated in a two-dimensionally inhomogeneous model. The longitudinal and transverse sounding curves are accepted as basic ones. The joint analysis of these curves and impedance phase pseudosections indicates geoelectric heterogeneity of the environment in the area of breakthrough magmatic melts named after S.I. Naboko. We obtained geoelectrical section using bimodal inversion of AMTS curves. The section contains a conductive heterogeneity, connected with the faults, through which fluids come to the surface. Along with AMTS we used MTS in a wide range for the study of the deep conductivity. These data point out crustal anomaly at depth of 15-35 km. According to AMTS, MTS and other geological and geophysical data the conceptual model of the area was compiled. It describes the possible nature of the anomalous zones. The work presents approximate estimations of the rock porosity in the fault zone through which magmatic melts come to the overlying strata in the breakthrough area named after S.I. Naboko.
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THE EARTH’S CRUST AND UPPER MANTLE OF KAMCHATKA FROM GEOPHYSICAL DATE
Moroz Yu.F., Gontovaya L.I.
Institute of Volcanology and seismology, Far East Branch, Russian Academy of Sciences
Deep magnetotelluric sounding (MTS) and seismic tomography data revealed key features in distribution of deep geoelectric and velocity heterogeneities. The upper mantle of Kamchatka consists of the asthenospheric conducting layer that rises from a depth of 120-150 km in Western Kamchatka up to a depth of 70-80 km beneath the current volcanism zone in Eastern Kamchatka. The uplift of the asthenospheric layer extends along the volcanism zone and lies above a seismofocal zone. The asthenospheric conducting layer corresponds to the asthenospheric low S- wave velocities layer under the current volcanism zone. We assume that the origin of the asthenospheric layers can be attributed to partial melting. At depths 10-40 km in the lithosphere, the geophysical data revealed horizontal zones containing high - conductivity and seismic wave anomalies likely associated with the areas of current volcanism. The observed anomalies in general are in agreement to each other and largely coincide. We assume that they reflect layering of the lithospheric zones, decompression, high porosity and saturation by liquid fluids (hydrothermal solutions and partial melts). In the areas of Klyuchevskoy and Avachinsky volcano groups, high asthenospheric layers correspond to high-conductivity anomalies and low-velocities anomalies that are likely related to the mantle rock melts that feed the volcanoes at depths 70-100 km. The seismofocal zone is characterized by complicated distribution of seismic wave velocities. Remarkably, that the low-velocity anomalies, the origin of which is a subject to detailed study, are observed within its boundaries.
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MAGNETOTELLURIC SOUNDING IN 3D-CASE (NUMERICAL SIMULATION)
Plotkin V.V., Gubin D.I.
IPGG SB RAS
The new technology of array magnetotelluric sounding (MTS) of the three-dimensional medium using the simulation of the field and MTS curve distortions by Treffts's method is offered. In cases of medium excitation by vertically incident plane wave, the lateral field non-uniformities registered on a surface are of certainly internal origin. Therefore for solution of the MTS forward problem, it is possible to apply boundary conditions of attenuation of all spatial harmonics of the field up in the atmosphere and deep into the medium. Advantage of technology consists in use for the solution of the inversion problem as input data of all standard MTS curves without any manipulations with them, and absence of need of the synchronous data registration on points. By analogy with time samples, it is offered to locate points on a uniform grid which sizes determine the smallest scales of determination of medium details by sounding. For optimization of medium model, it is possible to use the non-linear least-squares method including iterative process with computation of the sensitivity matrix and its singular expansion. Algorithm of MTS curve interpretation for the three-dimensional medium is tested using synthetic data.
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THE MULTIPATH FREQUENCY SOUNDING ONTO KOVDOR-YONA AREA OF THE KOLA PENINSULA
(EXPERIMENT "KOVDOR-2015")
Shevtsov A.N.1, Kolobov V.V.2, Zhamaletdinov A.A.1,2,3, Kolesnikov V.E.1, Skorokhodov A.A.1, Ryazantsev P.A.4,
Birulia M.A.5, Ivonin V.A.2
1 - Geological Institute of the Kola Sci. center RAS, Apatity 2 - Center of Physical and Technical Problems of the North
Energy of the Kola Sci. Center RAS, Apatity 3 - SPb Branch of the Pushkov Institute of Terrestrial Magnetism, Ionosphere and Wave propagation RAS, S.-
Petersburg 4 - Institute of Geology of the Karelian Research center RAS,
Petrozavodsk 5 - VEGA East European Geophysical Association, S.-Petersburg
Experiment Kovdor-2015" was provided by the plan of RFBR grant aimed to study the nature and structure of the electrical conductivity of the upper part of the crust within the first ten kilometers and, in particular, to study properties of the mysterious conductive layer of the dilatant-diffusive nature ("DD layer"). We discovered the layer for the first time in Finland in 1997, during the multipath frequency sounding experiment in Central Finland granitoid massif [Zamaletdinov et al., 2002]. The desire to learn is primarily determined by the fact that the "DD layer" is related with the presence of the fluids in the upper layer of the earth's crust, which get to a depth through the system of cracks, that flattening out with depth because of the influence of tangential stresses. The phenomenon of dilatancy and brittle fracture of rocks appearing while the process, according to the theory of V. N. Nikolaevsky, create the conditions for the existence of free fluids at depth. This, in turn, causes increasing of rocks electrical conductivity. To solve the main problem two systems of mutually orthogonal feed lines with a length of 1.5 km on the Western and Eastern parts of the Kovdor-Yona area were set and series of frequency multipath soundings at distances
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of 25 and 50 km away from each of the electrical dipoles were carried out. Measurements were performed using two types of digital stations – VMTU-10 and KVVN-7 – at each receiving point. The electromagnetic field was created in the frequency range from 2 kHz to 10 Hz. For this purpose the generator of the directed action "Energy-3M" connected to the dipoles AB, mounted on the chassis of the vehicle ZIL-131. The report presents the results of data processing and quantitative interpretation. The use of two measurement stations on each receiving point let significantly increase the reliability of processing results and the results of solving the inverse problem. In particular, we have got reliable response functions indicating the presence and parameters of DD-layer, as electric and horizontal magnetic components. This provides additional information for finding and counting static distortions.
ANISOTROPIC LAYER’S MODELING AT DECIDING OF TWO-DIMENSIONAL MAGNETOTELLURIC
PROBLEMS
Skorokhodov A.A.1, Vardanjants I.L.2
1 - Geological Institute, KSC, Apatity 2 - Saint-Petersburg State University, Saint-Petersburg, Russia
Group of magnetotelluric (MT) methods is one of the most widespread in structure geoelectric survey. Using of MT developed from decisions of one-dimensional problems (horizontally layered medium) to three-dimensional problems [1]. The actual task is researching of anisotropic properties of geological objects [2]. In this report the decision of two-dimensional direct task of MT on anisotropic layer in isotropic earth is offered. The aim of this work is to define properties of MT data on anisotropic layer by modeling. To succeed problem of mathematic modeling was set. This problem was decided by using the application package 2D2011 of two-dimensional modeling, creating by I.L. Vardanjants. This package calculates response of MT field by method of finite differences separately for TM-mode and TE-mode. Anisotropic layer’s model had been created by interleaving of conductive and isolative layers.
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Considered data compared with date considered from isotropic layer with identical thickness, transversal resistance, occurrence depth and angle of inclination. The differences allowed not only to identify existence of anisotropy but to estimate its parameters. Difference of levels of amplitude curves for E and H polarizations (through and across of geological strike) between isotropic and anisotropic cases is defined by anisotropic factor. For example, if factor equals 10, amplitude curves differs in 100 times (or 2 degrees) right over the layer. This difference is decrease with increasing of distance between layer and observation point. The results of this work were applied in processing of experimental data obtained from West Pechenga (Kola Peninsula, Russia), which is represented as anisotropic geological object. Anisotropic factor over the range 3 to 10 was estimated for some conductive structures. References: • Berdichevskiy, M.N. / models and methods of Magnetotelluric / M.N. Berdichevskiy, V.B. Dmitriev – “Nauchnyy Mir”, Moscow. – 2009. • Y. Li / Magnetotelluric inversion for 2D anisotropic conductivity structures / Y. Li, J. Pek, H. Brasse/ Kolloquium Elektromagnetische Tiefenforschung, Königstein. – 2003.
GPR STUDY OF THERMOCLINE IN THE FRESH WATER BASINS
Titov A.V., Bobrov N.Yu., Krylov S.S.
Saint Petersburg State University
Ground Penetrating Radar (GPR) became one of the most widely used geophysical tools in exploration geophysics. The wide range of different problems can be solved with GPR. Gradient media are between complex objects which are of special interest for scientists and engineers. Thermocline is an example of gradient medium which can be found in water basins. The thermal dependence leads to gradient change of dielectric permittivity. Thus the thermocline can be studied with GPR. Here the results of physical modelling of GPR signal propagation in the environment with thermal gradient and the field example are presented.
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The gradient medium was constructed in the laboratory in the special water-filled tank. The GPR “OKO-2” with 1700 MHz antenna was applied for laboratory experiments. We used infrared camera to visualize the thermal distribution in the tank. After data processing with the use of MATLAB package it was found that the time of electromagnetic pulse arrival corresponds to reflection from the top boundary of gradient layer. The characteristic reflections within water layer were detected at GPR records during test survey at fresh-water lake in Karelia. The instrument “OKO-2” with 150 MHz antenna placed at inflatable boat was used for the survey. Special water resistant thermistor chain using Arduino hardware was constructed for temperature measurements. The temperature data were collected simultaneously with GPR survey and real-time processed in MATLAB. It was found that the significant gradient of temperature is formed in the lake, and the reflections on the radargrams correspond to this gradient layer. Presented results demonstrate that the physical modelling helps to better understand GPR signal propagation in the complex media. The authors thank “Geomodel” Resourse Center for provided equipment.
THE GEOTHERMAL RESOURCES OF THE TERRITORY OF ARMENIA
Vardanyan K.S.
Institute of Geophysics and Engineering Seismology of the National Akademy of Sciences of Armenia
Modern tectonic activity in Armenia, extensive development of recent volcanic activity, significant manifestation of thermal mineral springs, high values of geothermal gradient and heat flow testifies to the probability of the existence in the depths of the masses, with very significant overheating, however, is still not detected objects on the territory of Armenia, with the prospect of cost-effective exploitation of underground heat.Currently, according to published and stock data, on the territory of Armenia the value of geothermal gradient are measured in about 150 wells, only in 80 of which the temperature measurements were accompanied by the definition of thermal conductivity values of core samples aimed to determine the heat
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flow values. In the central diagonal band of the area, a high level of deep heat flow is set; inside geothermal anomalies, the contours of more intensive local TF (thermal field) anomaliesare highlighted. The value of the observed TF are fixed, exceeding the calculated curve of spatial anomaly of Lesser Caucasus TF by 20-70mVt / m2, built according to the regional two-dimensional thermal model. Local anomalies of TF are concentrated in the area of intensive linear magnetic anomalies, also gradient zones of gravitational field are established, the deep fault zones, the zones across subvertical conductive channels. In some cases, local anomalies of TF are associated with secondary magma chambers. It is assumed that the mechanisms of formation of geothermal field deposits in conditions of Armenia can be associated with secondary (peripheral) magma chambers, and active zones of deep faults.
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S. SEISMOLOGY
INVESTIGATION OF MASS TRANSPORT IN THE EARTH'S SYSTEM WITH SATELLITE GRAVIMETRY
AND OTHER REMOTE SENSING TECHNIQUES
Ditmar P.
Delft University of Technology
The solid Earth, together with its “spheres” – hydrosphere, cryosphere, and atmosphere – form a single entity called “the Earth’s system. The Earth’s system is subject to multitude of processes. One of them is mass transport in (i) the solid Earth, (ii) hydrosphere/cryosphere, and (iii) atmosphere. The first two compartments are the focus of my presentation. In essence, the only tool to directly observe mass transport at a global scale is satellite gravimetry. This technique is in use since 2002, when GRACE satellite mission was launched. By collecting precise measurements of satellite motion, this mission allows tiny variations of the Earth’s gravity field to be detected. Those variations, in line with the Newton’s attraction low, can be converted into global mass anomaly maps. Such maps are typically compiled with a temporal sampling of one month and have a spatial resolution of about 300 km. Importantly, gravimetry can sense processes under the Earth’s surface. This make this observation technique unique, as compared, e.g., to the remote sensing techniques exploiting electromagnetic waves. As such, satellite gravimetry can be used to study the processes that are difficult of impossible to observe by other means. This includes, among others, overexploitation of groundwater resources in arid and semi-arid areas, as well as meltwater retention inside the ice sheets. Furthermore, by combining information delivered by satellite gravimetry with other satellite and in-situ data, one can obtain a more accurate and comprehensive description of processes in the Earth’s system, such as glacial isostatic adjustment, megathrust earthquakes, shrinking of ice sheets and glaciers, water cycle, and others.
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I stress that individual components of the Earth’s system are closely linked to each other. Studying one component without paying attention at other ones is not only inefficient, but may lead to an incomplete or even erroneous picture of the processes under investigation. This should be kept in mind, among others, in the development of educational programs. We should train students in such a way that they gain some knowledge about all components of the Earth’s system.
COMPARISON OF THE RESULTS OF SEISMIC METHODS T0′ AND FORWARD RAY TRACING ON
TRAINING PROFILE NEAR NOVOSIBIRSK
Eliseev A.A.
IPGG SB RAS
Many generations student – geophysicists Novosibirsk State University had training geophysical practice after the third year near village Burmistrovo Novosibirsk region. One of the tasks of practice - building seismic section by method t0ˈ (Plus – Minus), which strictly corresponds to the propagation Head waves. In addition to this method resistivity prospecting is applied and joint interpretation of results is carried. However you may check results of method t0ˈ (Plus – Minus) by decision forward kinematic problem. Method of forward ray tracing in program SeisWide [1] is the most suitable for this, where refracted and reflected waves are used. Forward problem by digitized model of method t0ˈ (Plus – Minus) was solved at the first stage. It found that: head wave is traced only small sites profile, which are divided extended shade zones and travel times of the waves in the first arrivals do not coincide with observed times by up to 15 ms. Minimum allowable velocity gradient in the layers was used for ensure continued wave tracking and the depth of the seismic boundaries and velocity layers needed to change to reduce the residual time. Second stage is applied method of forward ray tracing, in which hodographs were corrected and seismic section was built. Trial and error method was used in modeling, which enables localization isolated anomaly seeming velocity residual decreases to 3 ms. Availability of appropriate
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changes time in the system of direct and counter hodographs is requirement to justify heterogeneity. The resulting seismic section has fewer anomalies and the values of velocity and depth other than section by t0ˈ (Plus – Minus)
1. Zelt C.A., Smith R.B., Seismic traveltime inversion for 2-D crustal velocity structure. Geophys. J., 1992, 16-34 pp.
THE USE OF PARALLEL PROGRAMMING IN PROBLEMS OF EARTHQUAKE PARAMETERS
DETERMINATION
Fomochkina A., Bukchin B.
Institute of Earthquake Prediction Theory and Mathematical Geophysics RAS
Describing the seismic source in moment tensor approximation we consider instant point shear dislocation (double-couple) at the depth h. Such a source is given by five parameters: it's depth, focal mechanism determined by three angles (strike ψ, dip δ and rake λ) and seismic moment М0. Determination of focal mechanism and depth of the earthquake source by a systematic exploration of the parametric space and minimization of the misfit between observations and their theoretical values allows to assess also the level of parameters resolution. But this approach in the case of sufficiently high detail of the exploration requires considerable computer time. It is reasonable in the case of detailed study of seismic events, but does not provide the ability to quickly obtain preliminary estimates of the main parameters of the earthquake. The use of systematic exploration includes the so-called natural parallelism. Namely, the optimal solution search area can be divided into subregions. Each subregion is calculated on a separate processor/core (search a local minimum of misfit between the theoretical and the observed spectra) and then program choose the absolute minimum. Thus, we choose the combination of parameters at which this absolute minimum is attained. We discuss in the paper the application of methods of parallel calculations
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to speed up the determination of earthquake parameters. Our program uses OpenMP standard, which is designed for programming multithreaded applications on multiprocessor systems with shared memory. The results of use of such approach to study the strongest aftershock of the earthquake in Tohoku are presented.
REVEALING THE ANOMALOUS HIGH-VELOCITY BODY IN THE CRUST OF CRIMEAN MOUNTAINS BY
LOCAL SEISMIC TOMOGRAPHY
Gobarenko V.S.1, Yegorova T.P.2
1 - Institute of Seismology and Geodynamics, Vernadskii Crimean Federal University, Crimea, Simferopol
2 - Institute of Geophysics of National Academy of Sciecnes of Ukraine, Kiev
The Greater Caucasus and its north-western extension, the Crimean Mountains, represent the fold-and-thrust belt formed in the Cenozoic on the southern margin of the East European Platform due to collision between the Eurasian and Africa-Arabian plates. To get new constraints on the structure of transition from Crimea to Black Sea we are currently implemented local seismic tomography study onshore and offshore Crimea that uses the data from weak (mb≤3) earthquakes occurred within the Crimean seismogenic zone (CSZ), which controls the Main Caucasus Thrust. According to characteristic features of seismicity, 4 major subzones could be distinguished (from east to west) within the CSZ - Kerch-Taman, Sudak, South Coast (Alushta-Yalta) and Sevastopol ones. Seismotomographic model for the Kerch-Taman area has been built and published (Gobarenko et al, 2014;. Gobarenko et al, 2015.). This study presents the results of local seismic tomography study for South Coast (Alushta-Yalta) zone. To calculate velocity anomalies we used data on 370 weak earthquakes for the period 1975-2014, recorded by 4 permanent stations of seismological network of Crimea. The stations are located in Yalta, Alushta, Sevastopol and Simferopol. The number of seismic traces for calculations are 1140 and 1325 for P- and S- waves
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respectively. As a result of seismic inversion, a stable solution for velocity recovery has been obtained for the depth range of 10-30 km. The maximum density of seismic traces, attributable to the area between Yalta and Alushta, allowed to study the structure of the crust in this part of the Crimean Mountains and adjacent offshore area. In the middle crust of the study region a high-velocity anomaly is detected at a depth of 15-25 km, which extends in W-E direction from Sevastopol to Alushta. Seismic velocity reaches here 6.8 km/s and 3.8 km/s for the P and S-waves, respectively, and Vp / Vs - to 1.75-1.8. These results clearly indicate the presence of a high-velocity body in the crust of Crimean Mountains, which is traditionally assumed on the basis of strong (100 mGal) gravity anomaly over Crimean Mountains; but was not detected by seismic methods so far. The formation of such anomalous body in the crust of Crimean Mountains is considered in the framework of recent and on-going collision tectonics (wedging processes) by interaction and thrusting the suboceanic crust of the Black Sea under the southern margin of the Scythian Plate. Gobarenko V., Yegorova T., Stephenson R., 2014. The structure of the Kerch peninsula and north-eastern part of the Black Sea crust according to results of local seismic tomography // Geophysical Journal, 36, №2, 2014, P.18-34. Gobarenko V.,Yegorova Т., Stephenson R., 2015. Local tomography model of the northeastern Black Sea: intra-plate crustal underthrusting // Tectonic Evolution of the Eastern Black Sea and Caucasus. Geological Society, London, Special Publications. 2015, 428, http://doi.org/10.1144/SP428.2
AN ELECTRONIC FREEZEMETER
Gravirov V.V., Kislov K.V.
Institute of Earthquake Prediction Theory and Mathematical Geophysics RAS (IEPT RAS)
The question of study temperature distribution under the Earth's surface has already more than 100 years of study. During this time effect of soils temperature on the distribution of seismic waves was investigated rather complete. It was established that change temperature occur changes speeds of seismic waves. The most significant sharp jump in speeds occurs in
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freezing and melting of soils, that is at the transition temperature through the zero. It can be explained due different character phase transitions water-ice in the rocks with different dispersion and lithology. However, it is poorly understood the problem of the attenuation of high-frequency surface seismic waves at different thickness frost soil. Since in areas where there is no permafrost, depth soil freezing rarely exceeds 2 m, it may seem nonsense, but this question has important value for shallow seismic investigation, in determining the resolution of seismic stations, the study of seismic noise and other practical, scientific and methodological works. The relevance of these studies is increasing due to the permafrost retreat caused by global warming. For automated research the depths of freezing soil we developed a prototype of electronic freezemeter, which allows to determine the distribution of points freezing ground as depth as well as on the area. In addition, it allows us to trace the dynamics of temperature regime in a particular point observations. In the future this measuring system can find be used not only in seismology, but also in applications such as carrying out of work on the weak, loose, swampy soils to determine the possible load operating roads, shallow utilities, pipelines and so on.
DERIVATION AND GENERALIZATION OF THE OMORY LAW
Guglielmi A.V.1, Zotov O.D.2
1 - Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Moscow, Russia
2 - Borok Geophysical Observatory, Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, Borok, Yaroslavl
oblast, Russia
After the occurrence of the main shock, the source of the earthquake starts to relax. Speaking metaphorically, it gradually cools. However, this is much unlike the regular cooling of a heated homogeneous body. On the contrary, a source, which is a highly nonlinear structured system, undergoes complex processes manifesting themselves, in particular, by a sustained aftershocks. We present the known Omori law in the form of differential equation that
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describes the evolution of the aftershock activity. This aftershock equation is derived with taking into account deactivation of the faults in epicentral zone of the main shock. A generalization of the Omori law is proposed. We demonstrate the Aftershock equation in action by analyzing the earthquakes in California. Further research in this direction seems interesting and promising. Especially interesting is the search for precursors of strong earthquakes in the form of a specific variation of the deactivation factor of faults. The work was supported by the Program № 15 of the Presidium of RAS and RFBR (grant no. 15-05-00491).
THE DECADE OF CONTINUOUS SEISMOLOGICAL OBSERVATIONS ON VALAAM ISLAND
Karpinsky V.V.
St.Petersburg State University, St.Petersburg, Russia
The report presents scientific and historical basis of seismological station "Valaam": installation and analysis of data quality and registration facilities of the station. Presentation also contains the review of the local seismicity of the northern part of Ladoga lake.
ON THE PROBLEM OF THE APPLICATION OF DEEP NEURAL NETWORKS IN SEISMOLOGY
Kislov K.V., Gravirov V.V.
Institute of Earthquake Prediction Theory and Mathematical Geophysics (IEPT RAS)
Although the number of research studies in seismology based on an artificial neuron network (NN) technique has been increasing, the efficiency of these algorithms is limited. In recent years there has been a new glut of NN. The reason for it is the development of training methods
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for deep neural networks (DNN). DNN operate with data at higher-level. For pretraining of a network it is possible to use the unlabeled data and such network can be used for several tasks. The training requires a smaller number of labeled data, has a higher rate of learning and less error. We believe that this study may be an initial way to use the technology of DNN in seismology.
SURFACE WAVE TOMOGRAPHY OF THE CENTRAL EUROPE
Lyskova E.L., Koroleva T.Yu., Yanovskaya T.B.
Saint Petersburg State University
The data for surface wave tomography are group velocity dispersion curves of Rayleigh and Love waves obtained by frequency-time analysis from records of 41 earthquakes and from cross-correlation functions of the ambient noise registered at 45 European stations. Rayleigh wave dispersion curves were determined from Z components of the earthquake records and from Z-Z correlation functions of the noise, while for Love wave dispersion we used transverse components of the records and T-T correlation function of the noise. In total we obtained the dispersion curves along 887 paths for Rayleigh waves and along 858 paths for Love waves in the period range T=10-100 s. Using 2D tomography we constructed group velocity maps for a region of Central Europe for different periods
λ),(VT ϕ both for Rayleigh and Love waves. On the basis of these maps the group velocity dispersion curves (T)V(T)V LR and were calculated in some selected points λ,ϕ . These dispersion curves were inverted to vertical velocity sections for SV and SH waves from the curves for Rayleigh and Love waves correspondingly. A difference between the velocity sections indicates an existence of anisotropy of the upper mantle in the region under study.
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DEPENDENCE OF TRAVEL-TIME TOMOGRAPHY SOLUTION ON A STARTING MODEL
Medvedev S.V., Yanovskaya T.B.
St.Petersburg State University
The first step in solving any of travel-time tomography problems is linearization: a starting model is chosen, travel time residuals relative the model are calculated, and finally the problem is reduced to linear system of equations that relates the travel time residuals and parameters of the velocity correction relatively to the starting model. We show that such approach for solving the tomography problem leads to the solutions that depend on the choice of the starting model. We consider the tomography problem that uses travel times of diving waves when sources and receivers are located on a horizontal surface. In such a case the starting model is chosen as a function of only vertical coordinate V0(z) and the tomography problem is reduced to a search of the velocity corrections at different depths that depend on horizontal coordinates. The starting model should be chosen in a simple form (linear or piecewise linear function) in order to calculate travel times and the wave paths (rays) easily. The vertical section is divided by horizontal layers and horizontal velocity corrections are estimated in each layer. So the problem is formulated as a search of the corrections δVk(x,y) in each k-th layer, and the final solution is represented as V(x,y,z)=V0(z)+ δVk(x,y) where zk<z<zk+1. However it was found that such a solution depends on the starting model because the tomography solution depends on configuration of the rays and in turn on the starring model. This can be easily understood if the velocity corrections are assumed as constant values in cells: in different starting models the rays may cross different cells, so that the data (residuals) contain information about the velocity corrections in different cells. More appropriate method for solving such a problem was earlier proposed by one of the authors (Yanovskaya, 2009). The velocity corrections are assumed to satisfy a smoothness criterion analogous to that used in surface wave tomography. By numerical modeling we show that even similar velocity profiles V0(z) result in different solutions V(x,y,z) if the gradients
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of V0(z) are different. An approach for a proper choice of the starting model is suggested.
SEISMIC POTENTIAL OF THE BALTIC SHIELD AND RUSSIAN PLATE COUPLING ZONE ACCORDING TO
GNSS DATA
Mokhnatkin A.1, Assinovskaya B.2, Gorshkov V.1, Smirnov S.1, Scherbakova N.1
1 - CAO RAS (Pulkovo Observatory) 2 - GS RAS
The south-eastern part of the Baltic Region including the surroundings of Finnish depression are characterized by a few local active fault zones which show a weak seismicity sometimes, as well as the presence of regional geological structures extending from the southern coast of Lake Ladoga up to the western coast of Estonia. The Baltic Klint (associated with Polkanov’s marginal radial flexure) is one of them. The assumption about dynamic interaction of the Baltic shield and the Russian plate was examined using horizontal velocities data that was obtained from GNSS stations located on the East European Craton. Measurements of the plurality of GNSS stations in considered region were collected and uniformly processed using the GIPSY software toolkit. Then we found the magnitude that the Baltic shield and the Russian plate motion (rotation) relative to each other. In addition, deformation field for the part (area around the Gulf of Finland) of the coupling zone of two structures were estimated. This deformation field based on 26 GNSS-stations of Finland, Russia and Estonia is characterized by weak compression (3-4 nanostrains per year) in the northwest–southeast direction. It may be concluded that the Baltic shield and the Russian plate can be considered as a single whole in a geodynamic sense. Moreover, for the Baltic Klint area deformations in plane that tangent to the Earth surface for each site i. e. horizontal deformations is free from any anomalies. It should be emphasized that the results for deformation field are valid for a given
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GNSS stations spatial distribution and fixed scale factor.
APPLICATION A DOUBLE-DIFFERENCE EARTHQUAKE LOCATION ALGORITHM TO MICROSEISMIC MONITORING DATA FROM
PYHÄSALMI MINE, FINLAND
Nevalainen J.1, Usoltseva O.2, Kozlovskaya E.1,3
1 - Sodankylä geophysical observatory, University of Oulu 2 - Institute of Geosphere Dynamics RAS
3 - Oulu Mining School, University of Oulu
Pyhäsalmi mine is one of the oldest and deepest underground mines in Europe. Current mining operation concentrates around deep ore body located from 1050 m down to 1450 m below surface. The microseismic monitoring system designed by Integrated Seismic System International Ltd has been installed around deep ore body and consists of 19 geophones. The system enables automatic picking of P- and S-wave arrivals and location of microseismic events caused by mining activities and manual check of the location results as well. Each month near 1000 microseismic events (Mw -1.8 to 2.2) are registered. Most events occur in localized clusters. The location error varies from 5 to 30 meters. The improving of location uncertainties and detailed knowledge about cluster position is necessary in order to estimate seismic hazard in the area and to understand the influence of mining technology to mining-induced seismicity. We modified standard double-difference relocation code (HypoDD) for Cartesian coordinates and different depths of stations. We tested our algorithm with synthetic data in order to investigate whether the HypoDD algorithm can be applied to events located at small distances from each other and from geophones by HypoDD. We also investigated precision of relocation for our network configuration. For Pyhäsalmi mine the seismic activity was analysed for different 2-4 week’s time periods with the help of HypoDD. The results showed that more concentrate accumulation of events in clusters is observed after relocation. The results of our research can be applied in further analysis of
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microseismic networks data and they also show the possibility of using the HypoDD in investigation of induced seismicity.
THE LONG-TERM EARTH’S DEFORMATIONS FROM SEISMOGRAVIMETER DATA AT SAINT-
PETERSBURG
Petrova L.N.
Saint Petersburg State University
The long-term resistant deformations with the duration of 1.5‒2 days were first revealed before the earthquake in northern Iran on March 14, 1998 (M=6.9). Similar deformations were later registered prior to some seismic events ‒ the earthquake in Turkey on August 17, 1999 (M=7.8), the earthquake in Taiwan on September 20, 1999 (M=7.7) and etc. The existence of this phenomenon has been retrospectively confirmed in 1998 and 1999 by the analysis of synchronous observations at the GEOSCOPE network stations HYB, WUS and SSB. In December 2004 the tension-compression deformation was registered at Saint-Petersburg from December 1 to December 12 with the duration of 12 days. the strong seismic activity, including the Macquarie (December 23, 2004; M=8.1) and Sumatra (December 26, 2004; M=9.0) earthquakes. Immediately ahead of the earthquake on the Macquarie Island the tension-compression deformation with 2 days duration was registered in the period from December 21, 2004 to December 23, 2004. Analysis of the background seismogravitational process in 2005‒2011 has revealed that from time to time even more long-durational deformations take place. For instance, at the period from May to December 2005 after 3 phenomena with the 1 month duration the 2 most long seismogravitational deformations were registered with duration of 81.6 and 98.77 days. In 2011 only one deformation was detected with duration of 44.8 days. The comparison of the sequences of strong and especially deep earthquakes that occurred at the relevant time with the dynamics of seismogravitational process revealed the following pattern. The rupture at the earthquake focus goes on when the acceleration is rapidly changing or, in other words, when the force associated with acceleration changes its magnitude or direction.
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An attempt to evaluate the amplitude of acceleration variation for very long-term oscillations connected with the seismogravitational tension-compression deformations in comparison with the natural period of pendulum was made in this study. It is possible to make on the basis of the frequency response of a seismograph with damping D = 0.7 (like we have), if we assume that there is a linear relationship between the very low frequency of these oscillations and the frequency is 2 times more than the natural frequency of the pendulum. Taking into account the natural period of pendulum (13 sec), the damping factor (0.7), the linearity of the photoelectric transformer characteristic and its sensitivity (4.5 V/mm), we obtained that the amplitudes of anomalies are equal 28.65 mGal and 0.26 mGal in 2004, 48.53 mGal ‒ in 2011 and 188.72 mGal and 256.6 mGal in 2005 respectively. Except 2005 the estimates of the received amplitudes are quite comparable to the amplitude of the theoretical tide which is carried out for December, 2004. However, oscillations with a period of about 1 month can not be due to the tide, as they were not observed in other years. The calculation of the tidal amplitudes demonstrates that the monthly amplitude envelope has to be higher than 40 mGal in the periods from December, 5 to December, 10 and from December, 20 to December, 25 with the maxima 60 mGal on December, 7 and December, 22 respectively. The minimum of the tidal amplitude envelope for the period December 14 ‒ 16 has been calculated and it is equal to 20 mGal. There were not significant variations of these values in other times. The amplitudes of seismogravitational deformations in 2005 are rather higher. They are 0.0193 and 0.0265 % of the gravity force g, respectively. It is quite high value. The explanation of the reason can likely be in the movement of an internal solid kernel relative to the center of the planet.
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CONCERNING THE ORIGIN OF THE RARE FEBRUARY 1, 2011, Mw=4.7 EARTHQUAKE IN
WESTERN TRANSBAIKALIA
Seredkina A.I.1,2
1 - Institute of the Earth’s crust SB RAS, Irkutsk, Russia 2 - Diamond and Precious Metal Geology Institute SB RAS,
Yakutsk, Russia
We describe major parameters and tectonic settings of the rare February 1, 2011, earthquake (Mw=4.3) in western Transbaikalia. It was confined to the zone of contact between the slope of the Zagan range and the Tugnui basin. From geological point of view this structure is a Zagan metamorphic core complex (MCC). For the instrumental observation period (1957–2015) in the study area, the Zagan earthquake became the second most important seismic event after the October 2, 1980, М=5.1 earthquake located near the Orongoi basins. Earthquake source parameters (hypocentral depth, moment magnitude, scalar seismic moment and focal mechanism) have been determined from the data on amplitude spectra of surface waves and the first body-wave arrivals recorded on regional stations. The results obtained have shown that the origin of this event was formed in the conjunction zone between the listric fault and main detachment fault plane and thus was controlled by the MCC structure. Local extension processes are typical for MCCs and in this case manifest in normal-fault displacement along low-angle dipping rupture plane in the earthquake origin. This fact correlates with numerously published relationships between regular trends in the MCC structures and their-confined earthquake focal mechanisms in different regions of the Earth. To sum up, the data obtained on the Zagan earthquake contribute to our knowledge about development of present-day structures in Transbaikalia. This work was supported by the grant of the Russian Scientific Fund, project No 15–17–20000.
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DEEP VELOCITY STRUCTURE OF THE UPPER MANTLE IN ASIA BASED ON DISPERSION OF
RAYLEIGH AND LOVE WAVES
Seredkina A.I.1,2, Kozhevnikov V.M.1, Solovey O.A.1
1 - Institute of the Earth’s crust SB RAS, Irkutsk, Russia 2 - Diamond and Precious Metal Geology Institute SB RAS,
Yakutsk, Russia
Mantle structure in Asia (40°–60° N, 80°–130° E) was investigated from the data on dispersion of the fundamental mode of the Rayleigh and Love wave group velocities along more than 3200 earthquake-station paths for each surface-wave type. The dispersion curves were processed by a frequency-time analysis procedure at periods from 10 to 250 s. The group velocity maps were computed separately for each period, at different sampling intervals. We used a tomography method developed for spherical surface. Resolution was estimated according to the effective averaging radius and presented likewise in the form of maps. For the major part of the investigated area the horizontal resolution is about 300 km. To estimate the depths of the inhomogeneities and to calculate the anisotropy coefficient, locally averaged dispersion curves were calculated using the group velocity maps, with reference to the radius R, and were then inverted to SV-and SH-wave velocity-depth profiles. The obtained results show that anisotropy is observed in the upper mantle up to the depths of about 250 km (i.e. in the asthenosphere) and it is the most prominent in the depth interval from the Moho to 150 km. The upper mantle under the Siberian platform is characterized by the minimum anisotropy coefficient (~1.5 %). Maximum anisotropy is seen in the area of the Japan sea coast (~5.0 %). The local maximum of the coefficient values is observed under the northeastern flank of the Baikal rift at the depths from 70 to 125 km. This work was supported by the grant of the Russian Scientific Fund, project No 15–17–20000.
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APPLICATION OF A SIMULATED ANNEALING METHOD FOR DETECTION AND MEASUREMENT
OF PARAMETERS OF PKIIKP WAVES
Usoltseva O.A., Ovtchinnikov V.M.
Institute of Geosphere Dynamics RAS
Study of the contact zone between the inner and outer core represents considerable interest for understanding of the Earth's core dynamics. One of sources of data about the processes proceeding in the top part of the inner core up to the depth of 100 km is the seismic phase PKIIKP reflected from an internal surface boundary between the liquid and the solid core. Amplitudes of these phases bearing information on the velocity of shear waves in the top part of the inner core in the distance range from 175o to 180o are in most cases small and therefore them detection is complicated without application of special techniques. We propose to determine the phase PKIIKP parameters by nonlinear inversion with using the simulated annealing method. We estimated relative amplitudes and relative times of delay for each phases by using L1-norm and the simulated annealing method. Testing of algorithm was held on synthetic seismograms. It was received that amplitude of PKIIKP for the IASP91 model makes 4-10% of PKPdf wave amplitude in the distance range from 175o to 179.5o and 16-47% for model with the shear wave velocity is equal of 0 km/s in most top part of the inner core. Efficiency of algorithm was also checked on synthetic seismograms with addition of noise correlated with PKPdf. Criteria of stability of the decision were defined by a variation initial and boundary conditions. The accuracy of determination of PKIIKP parameters was also estimated for different signal to noise ratio. Seismograms of the stations GZH, ENH, XAN (China), TAM (Algeria), which registered earthquakes at antipodal distances, had been analyzed by an annealing imitation method. As selection criteria of earthquakes were small duration of the source time function (less than 6.4 s) and large amplitude of PKPdf wave. It was shown there were PKIIKP phases with positive, negative, and zero amplitude.
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FEATURES AND GENERATION MECHANISMS OF SUBVERTICAL CLUSTERS OF EARTHQUAKE FOCI
Zakharov V.S.
Lomonosov Moscow State University, Faculty of Geology
We detect isometric in the plan almost vertical cluster of earthquakes (seismic "nails") in various regions of the world. The vertical size of the seismic "nails" is from 10 to 90 km, most of earthquakes are weak, and the formation time is from 10 to 60 days. We analyzed the spatial and temporal characteristics of the seismic "nails." Some of the "nails" are associated with large earthquakes or volcanic eruptions. For a number of seismic "nails" a clear relationship with the fault zones and other tectonic structures isn't revealed. In some cases, poorly expressed trends in the sequence of the foci depth are detected. The Hurst exponent values (H> 0.5) indicate the persistent behavior in the sequence of the earthquake’s depths. This result agrees with models of self-organization with a positive feedback loop in the interaction of fluid flow and tectonic deformation to explain the mechanism of earthquakes. Features of change in the number of earthquakes per day in the formation of seismic "nails" are in good agreement with the dynamics of acoustic emission in initiating by water as a result of long experiments. The most likely mechanism for the generation of seismic "nails", not related to large earthquakes is the activation of seismicity by fluids.
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SEMP. SEISMO-ELECTROMAGNETIC PHENOMENA
VARIATIONS OF IMPULSIVE NATURAL VLF SIGNALS PASSING OVER EPICENTERS OF
EARTHQUAKES BY OBSERVATIONS IN YAKUTSK
Argunov V.V.
Institute of Cosmophysical Research and Aeronomy SB RAS
For distant monitoring of disturbances in the lower ionosphere signals of low-frequency radio stations are often used. In particular, the method is used for investigation of ionospheric responses (disturbances) caused by seismic activity. As a variant of this method for the detection of seismic disturbances in the ionosphere one can use natural radio signals - an electromagnetic radiation of thunderstorm discharges (atmospherics). The examples of the effects of three earthquakes in the variations of average amplitude of atmospherics received in Yakutsk (φ = 62.1° N, λ = 129.7° E) were considered. The increase of signal amplitude for some days before the events can be considered as a precursor. It allows to used observations of impulse electromagnetic thunderstorm signals as one of possible means of distant monitoring of strong earthquakes.
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THE MAGNETOSONIC WAVES IN THE MID-LATITUDE IONOSPHERE APPEARING WITHIN
PREPARATION PHASE OF STRONG EARTHQUAKES
Barkhatova O.M.1, Barkhatov N.A.2, Kosolapova N.V.2, Yagodkina O.I.3
1 - Nizhny Novgorod State University of Architecture and Civil Engineering
2 - Nizhny Novgorod State Pedagogical University 3 - Polar Geophysical Institute
The occurrence of magnetosonic (MS) waves was observed during the preparation phase of four strong (M > 6.5) earthquakes around their future epicenter areas at the middle (35˚ - 40˚ N) and low (10˚ S - 10˚ N) latitudes. The simultaneous disturbances of ionospheric layers concentration and the geomagnetic field is a special feature of detected waves. The MS waves registration was performed by data of magnetic and ionospheric stations located near to the earthquakes epicenters. For each event the considered time interval included 3 days before the event, the day of the event and 3 days after them. The dynamic spectrum maximums of ionospheric layers Es, E, F2 critical frequencies and X, Y, Z geomagnetic field components for each day were compared. The fact of MS wave passage was fixed in case of simultaneous disturbances in spectrums of ionospheric layers critical frequencies and geomagnetic field components. According to received results a marked increase of MS disturbance number around the epicenters at two days before the earthquake for all four events was revealed. This result shows that the MS waves in the ionosphere may perform as earthquakes precursors. The lowest damping directions for the MS waves propagation was defined. In most cases they coincide with geomagnetic field direction and it is most clearly for X-component. The research results may be useful for studying of strong earthquakes preparation and development of mechanisms, as well as for the purpose of earthquake prediction by geophysical data.
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ANALYSIS OF A FEW MATHEMATICAL MODELS OF QUASI-STATIONARY ELECTRIC FIELDS
PENETRATION TO THE IONOSPHERE THROUGH THE EARTH’S ATMOSPHERE
Denisenko V.V.1,2, Kitaev A.V.1, Boudjada M.3, Lammer H.3
1 - Institute of Computational Modelling, Krasnoyarsk,Russia 2 - Siberian Federal University, Krasnoyarsk,Russia
3 - Space Research Institute, Graz, Austria
A quasi-stationary three-dimensional model of electric fields and currents in the conductor that includes the Earth’s atmosphere and ionosphere is used to analyze well known models of the lithosphere-ionosphere electric coupling. The height distribution of the components of the conductivity tensor above the altitude of 90 km is derived from the empirical models IRI, MSISE, IGRF. We use an empirical model by Rycroft and Odzimek (2011) below 50 km where the electric conductivity is isotropic with smooth interface between these regions. The steady state electroconductivity problem is numerically solved using Fourier transformations in horizontal directions. We set the input parameters which look typical for moderate earthquakes like vertical electric field of about 100 V/m near ground with typical horizontal scale of a few hundred km. The result electric field in the ionosphere in such a case does not exceed 1 µV/m under night-time conditions and it is about ten times less under day-time ones. This means that penetration of the large scale electric field from ground into the ionosphere cannot be a physical process which creates ionospheric precursors of earthquakes which are observed in range of a few mV/m. Also we discuss the extrinsic current models due to the diffusion and the convection in the Earth’s atmosphere. This research is supported by grant 15-05-00879 from the Russian Foundation for Basic Research.
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MODELING OF SEISMIC-ELECTROMAGNETIC PROCESSES IN HETEROGENEOUS MEDIA WITH
HIERARCHIC CONDUCTIVE, MAGNETIC, ELASTIC AND DENSE INCLUSIONS
Hachay O.A.1, Khachay O.Yu.2, Khachay A.Yu2
1 - Institute of geophysics UB RAS 2 - Ural Federal University
Purpose. Geological medium is an open system which is influenced by outer and inner factors that can lead it to a unstable state. That non stability is as a rule occurred locally and these zones are named as dynamically active elements, which are indicators of potential catastrophic sources. These objects differ from the embedded geological medium by their structural forms, which often are of hierarchical type. The process of their activisation can be searched, using wave fields monitoring. For that purpose it is needed to develop new algorithms of modeling wave fields propagation through the local objects with hierarchical structure. Also it is needed to develop new theory of interpretation the distribution of wave fields for defining the contours of these local hierarchical objects. Design/methodology/approach. It had been constructed an algorithm for 3D modeling electromagnetic field for arbitrary type of source of excitation in N-layered medium with a hierarchic conductive and magnetic intrusion, located in the layer number J. It had been constructed algorithms for 2D modeling of sound diffraction and linear polarized transversal seismic wave on an anomaly elastic or dense intrusion of hierarchic structure, located in the layer number J of N-layered elastic medium. We used the method of integral and integral-differential equations for a space frequency presentation of wave fields distribution. Findings. From the theory it is obviously that for such complicated medium each wave field contains its own information about the inner structure of the hierarchical inclusion. Therefore it is needed to interpret the monitoring data for each wave field apart, and not mixes the data base. Practical value/implications. These results will be the base for constructing new systems of monitoring observations of dynamical
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geological systems. Especially it is needed to prevent rock shocks in deep mines by their exploitation or natural hazards.
RESEARCH OF LITHOSPHERE-IONOSPHERE RELATIONSHIPS BY OBSERVATIONS RADIO
SIGNAL AMPLITUDE VARIATIONS IN THE RANGE OF 16-60 KHZ, REGISTERED IN TIKSI
Karimov R.R., Argunov V.V., Korsakov A.A.
Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy of Siberian Branch of the Russian Academy of Sciences
Experimental research on the registration data of the electric component of the electromagnetic radiation of signal amplitude variations in the range of 10-60 kHz is carried out in of ShICRA SB RAS. Registration data for different propagation paths of radio signals in the Earth-ionosphere waveguide allow studying the lithosphere-ionosphere for seismic events in the area of the Aleutian Islands, Kamchatka, in Japan and in the Lake Baikal region. During the period of registration from September 2015 to June 2016, the seismic effects in variations of the radiowaves amplitude were detected. Increasing of the signal amplitude, which occurs a few days before the seismic events, can be viewed as a precursor to earthquakes. The disturbances in the lower ionosphere, caused by lithospheric processes, also may occur in the VLF-signals of lightning, which propagated over the earthquake epicenter. This makes it possible to attract the observation signals of low-frequency radio signals and electromagnetic lightning impulse signals as possible method of remote monitoring of large earthquakes. Synchronized data on variations in radio signal amplitude and lightning origin VLF signals for stations Tiksi and Yakutsk will increase the spatial resolution of the scan azimuth seismic events.
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INVESTIGATION OF THE MAGNETIC FIELD DISTURBANCES FROM THE CATASTROPHIC
TSUNAMI OF 11.03.2011 IN JAPAN
Kopytenko Yu.A.1, Ismagilov V.S.1, Hayakawa M.2
1 - SPBF IZMIRAN, St.-Petersburg, Russia 2 - Institute of Seismo Electromagnetics, Chofu Tokyo, Japan
Catastrophic earthquake with magnitude M=9 happened 11.03.2011 at 05:46:24 UT near the eastern coast of Japan. This earthquake was strongest in the known Japan history. The earthquake epicenter was located ~373 km from Tokyo. The earthquake stimulated the catastrophic tsunami at Japan coast. In this work, we investigate magnetic field variations in the coastal zone induced by tsunami movement. Data of six three-component magnetic stations situated in the coastal zone of Japan were used in this work. Comparing magnetic and seismic variations, we found that the seismic signal arrived ~1 minute earlier at the magnetic observation Esashi (seismic is situated very close to the Esashi). We observe magnetic field variations with period T=30-40 s in contrast to seismic field variations. It is possible that these magnetic field variations are closely related with process of the tsunami origination. Decreasing in Z component value (~3 nT) just after the main seismic shock can arise from a vertical displacement of a part of the ocean crust as a result of the EQ. These peculiarities of the magnetic field variations arising ~ 6 minutes before the tsunami wave arriving at the coastline could be used for tsunami early warning.
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THE RESULTS OF MONITORING THE ELECTRICAL CONDUCTIVITY OF THE LITHOSPHERE IN
SUBDUCTION ZONE OF KAMCHATKA
Moroz Yu.F.1, Smirnov S.E.2
1 - Institute of Volcanology and seismology, Far East Branch, Russian Academy of Sciences
2 - Institute of Cosmophysics Research and Radiowave Prorogation, Far East Branch, Russian Academy of Sciences
Secular changes of the lithospheric electric conductivity were analyzed based on the monitoring data of the Earth’s electric field over the period from 2001 to 2014. Those measures were carried out in Verchniya Paratunka, Tundroviy, and Shipunskiy that are located alongside the coastline of the Avacha Bay of Kamchatka and where the catastrophic earthquake is to be expected according the long-term forecast. It is noticed that the changes in behavior of the secular movements of the lithospheric electric conductivity sannual average values represented with changes at along and transverse directions of the seismic focal zone extension. A great many of such changes were detected on the Shipunskiy peninsula. It is not impossible that such changes can be regarded to as the preliminary events of the intensive Jupanovskiy earthquake (Mw=7.1 30.01.2016). Identified changes of the lithospheric electric conductivity are connected with the influence of the conductivity of the deep faults on the Shipunskiy peninsula that is also likely changing in the presence of saline fluids in the faults due to the contraction and tension processes in the Earth crust at geodynamic processes in subduction zone. The data of the numerical 3-dimentional magnetotelluric field modeling confirmed the lithospheric electric conductivity changes being due to the deep faults conductivity influence.
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FEATURES OF BEHAVIOR OF THE SECULAR VARIATION OF THE VERTICAL GEOMAGNETIC
FIELD IN KAMCHATKA
Moroz Yu.F.1, Smirnov S.E.2
1 - Institute of Volcanology and seismology, Far East Branch, Russian Academy of Sciences
2 - Institute of Cosmophysics Research and Radiowave Prorogation, Far East Branch, Russian Academy of Sciences
Secular changes of the geomagnetic field vertical component data for the time period from 1966 to 2014 obtained from the observatories of Paratunka (Petropavlovsk-Kamchatsky), Kakioka (Honsu island), Mamambetsu (Hokkaido island), and Patrony (Irkutsk) were gathered and analyzed. Comparative analysis of secular movements showed that the same changes of approximately several hundred nT in strength were pronounced at all the four observatories for the period from 1968 to 2001. Then, concerning to the time period from 2001 to 2014, the situation had changed. In the observatory of Paratunka the secular movements were different from the other observatories data. The three observatories revealed variations were failed to confirm by this one. This deviation of secular movements of geomagnetic field is timed to the intensification of seismicity at a depth of 400--700 km in the South Kamchatka area where the strong Okhotomorsk earthquake of Mw=8.3 occurred. Now it is supposed that the physical-chemical processes activated as a result of the intensification of seismicity in the boundary between the upper and lower mantle. These processes to be the cause of large-scale geoelectrical in homogeneity the vertical component of geomagnetic field behavior is affected by.
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ON DELIVERY OF THE SEISMOGENIC ELECTRICITY TO THE IONOSPHERE
Namgaladze A.A., Karpov M.I.
Murmansk Arctic State University
Many researchers believe that the main cause of the ionospheric effects of the earthquake preparation is the allocation of soil radioactive gases from the tectonic faults, such as radon that enhances the ionization of the atmosphere near the Earth surface. However, the resulting charges and the corresponding seismogenic electric fields are too weak, and the conductivity of the lower atmosphere is too low to allow these fields to overcome the shielding effect of the ionosphere and to penetrate it. Another thing, if the solid or liquid aerosols moving vertically are present in the atmosphere, and the primary charges generated by radon or cosmic radiation attach to them. Charged aerosols recombine very slowly, the total number of charges increases, and they move upwards with a turbulent flow of an aerosols. Thus, the extraneous electric currents are generated mainly by a non-electrical and mechanical forces, which create a turbulent diffusion. Brought from below the electric charges create the seismogenic electric field in the ionosphere, which drives the ionospheric plasma and generates the observable ionospheric effects of earthquake preparation. This scheme is confirmed by satellite observations and model calculations. It is the same both for the thunderstorm activity, charging the ionosphere in the global electric circuit, and for the preparation processes of the strong earthquakes.
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ELECTRICAL TRIGGERING OF EARTHQUAKES: INSIGHT FROM LABORATORY EXPERIMENTS
Novikov V.A.1, Ruzhin Yu.Ya.2, Okunev V.I.1, Klyuchkin V.N.1, Shen X.3, Liu J.3
1 - Joint Institute for High Temperatures of RAS 2 - Pushkov Institute of Terrestrial Magnetism, Ionosphere and
Radio Waves Propagation of RAS 3 - Institute of Crustal Dynamics of CEA
In spite of sufficiently large number of published papers with results of field and laboratory experiments on a study of triggering impact of electric current on rocks under critical stress-strain state, a question on a possibility of earthquake triggering by electrical pulses is still under discussion, because the epicenters of earthquakes assumed as triggered by electrical actions are located at the depth of 5-10 km where estimated electric current density in the earth crust generated by artificial power unit is very low (~10-7-10-8 A/m2). This paper represents results obtained under lab conditions of the spring-block models, when for the first time a possibility of triggering the macro-events (lab "earthquakes") by a pulses of electric current applied along the model fault area was verified. In contrast to previous experiments carried out at press equipment, when only acoustic emission of the stressed rock specimen under electrical impact was analyzed, in the present study a spring-block facility was used, based on the earthquake model as an unstable slip of rock blocks, which allows to investigate not only the behavior of acoustic emission (generation of cracks at micro level), but also a possibility of triggering the macro events (abrupt slips of movable block – laboratory "earthquakes") by electric pulses. For the first time for high normal pressure of 50 MPa a possibility of electric triggering of seismic event by electrical pulses was demonstrated. The following preliminary results on the threshold values of electrical triggering lab "earthquake" is triggered at the shear stress of 0.98-0.99 of critical value; 2) minimal electrical current density for slip triggering is 25 A/m2. The reported study was funded by RFBR according to the research projects No. 15-55-53104, 14-05-00756, and by Natural Science Foundation of
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China according to International Cooperation project No. 41511130032.
DETECTION OF VLF⁄LF SIGNALS SENSITIVITY TO THE EFFECT OF SEISMIC AND GEOMAGNETIC
ACTIVITY ACCORDING TO THE MONITORING IN THE KURIL-KAMCHATKA REGION
Popova I.V.1, Rozhnoi A.A.1, Solovieva M.S.1, Levin B.V.2, Chebrov D.V.3
1 - Institute of Physics of the Earth 2 - Institute of Marine Geology & Geophysics 3 - Kamchatsky Branch of Geophysical Survey
We propose a neural network method for estimation of the VLF/LF (Very Low Frequency/Low Frequency) signal sensitivity to seismic and geomagnetic activity using representative database. It includes both the amplitudes and phases of VLF/LF subionospheric radio wave signals (10-50 kHz) measured over three years of monitoring of the Kuril-Kamchatka region and the seismicity parameters of the region. The relationships between the characteristic features of the VLF/LF signal for five days before the seismic events and corresponding level of seismicity are established in the process of neural network teaching on the examples of database. The neural network is trained also to distinguish the disturbed and quiet signals. Firstly we applied the trained neural network to detect anomaly changes in the VLF/LF signal indicating the seismicity of magnitude M ≥ 5.5 on the set of time intervals that include the day of seismic event. The neural network has detected changes in VLF/LF signal indicating the earthquake for nine of the twelve time intervals. We also examined the trained neural network on the set of time intervals which excluded the days of seismic events of magnitude M ≥ 5.5. Besides the considered time intervals did not include the days when the index of the magnetic field activity, Dst, and the flux of relativistic electrons exceeded the given thresholds. The results of this study showed that the neural network can distinguish the signals disturbed by seismic activity and the
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quiet ones. Then the trained neural network was used for detection of anomaly changes in the VLF/LF signal caused by magnetic storms. The neural network has found the changes in the VLF/LF signal indicating the magnetic activity for five of the six time intervals. The results of this research revealed that the character of changes in the VLF/LF signals indicating the earthquake and the magnetic activity looks different in time.
SEISMOMAGNETIC EFFECT IN FAULT ZONES
Riabova S.A., Spivak A.A.
IDG RAN
Dynamic of Earth's crust deformation and the formation of modes of geophysical fields in the surface layer of Earth's atmosphere is largely determined by presence and dynamic characteristics of fault zones. The research of geophysical fields and their variations particularly in zones of tectonic disturbances is of considerable interest in addressing the fundamental problems associated with the establishment of mechanisms for interaction between geospheres, transformation of energy fields of different physical nature, etc. The need for such research is also important in terms of the growing interest in the improvement of existing and development of new advanced methods of diagnosis geodynamic state of the Earth's crust. In addressing these issues increasing the sensitivity of the geodynamic control of local areas of the crust and the reliability of the mapping, the most dangerous in terms of loss of mechanical stability zones (for example, fractures) is claimed in the selection and justification of sites for construction of especially responsible structures and increased risk objects (NPP, pipeline transportation, etc.), as well as ensuring their long-term safe operation under conditions of increased risk from natural and man-made influences. The enhancement of diagnostic methods of rock massifs should be carried out in order to control and prevent the catastrophic consequences of natural phenomena (slope phenomenon, collapse of caverns, etc.). We are interested in well-known seismomagnetic effect, manifesting the appearance of geomagnetic variations at Earth's crust surface in the propagation of seismic waves. The available experimental data show that as
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the main factor determining the intensity of the electric and magnetic effects is environment heterogeneity. This heterogeneity of the medium structure, the presence of the interfaces between the rocks of different material composition, areas of medium disturbance and different stress-strain state helps to transform mechanical energy into electromagnetic energy. Although a significant amount of the research, issues related to the establishment of the quantitative relationship between the intensity and the amplitude of the seismic action caused by geomagnetic variations, as well as influence of the fault zone on the value seismomagnetic effect to date are not considered in detail. The present research examines the role of the internal structure of the fault zone on the spatial distribution of geomagnetic variations at Earth's crust surface caused by seismic wave propagation of different origin. The central part of the East European platform, located in the northern part of the Tula region of Russia was chosen as the object of research. Three-component seismic acquisition was performed in the frequency range 0.5 - 40 Hz using short-period seismometers SM-3KV. Measurement of geomagnetic variations in the seismic frequency range were made using induction magnetometers MIN-RF-002, which were placed on anti-vibration suspensions. Seismic sources were massive explosions, conducted in open pits of Moscow, Tula, Vladimir and others regions. The data of instrumental observation is shown that the propagation of seismic waves through the fault zone causes a variation of the geomagnetic field, significantly higher than background. The detailed analysis of the variations in seismic and geomagnetic fields indicates a locality of this effect. We obtain the relationships between the amplitudes of the induced seismomagnetic effect and seismic signal depending on the distance from the middle line of the fault. It was shown that the amplitude of seismomagnetic effect is maximal in the zone of influence of the fault and decreases markedly with distance from the fault.
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THE LOWER-IONOSPHERIC PERTURBATIONS AS A PRECURSOR TO THE NEPALESE EARTHQUAKES IN
APRIL-MAY 2015
Rozhnoi A.1, Solovieva M.1, Fedun V.2, Srivastava A.3
1 - Institute of Physics of the Earth, RAS, Moscow, Russia 2 - University of Sheffield, Sheffield, UK
3 - Indian Institute of Technology, Varanasi, India
The data recorded by the very low and low frequencies (VLF/LF) stations in Bishkek (Kirgizstan) and Varanasi (India) was used for the analysis in connection with the earthquakes in Nepal in April-May 2015. The strong shake with Mw=7.8, depth 15 km occurred on 25 April 2015, the second Nepalese earthquake happened on 12 May the same fault with Mw=7.3, depth 18 km (USGS/NEIC). The significant negative nighttime amplitude anomalies for the four paths crossing the area where the possible precursors of the earthquake can be found were observed 4-5 days before the first earthquake. Then after several days when the signals were quiet, the second series of anomalies could be seen before the second earthquake. These anomalies continued after the earthquake during the period of aftershock activity. Taking into account the possible influence of other factors which can produce perturbations in VLF/LF signals (geomagnetic storm, proton burst and the relativistic electron fluxes, as well as atmospheric parameters) and rejecting them, also using control paths, we may conclude that observed anomalies were caused by impending earthquakes. The fact that anomalies have been also observed in the two other paths from the VTX transmitter which were entirely in the area of possible appearance of earthquake precursors, give us information about earthquake intensity.
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EARTHQUAKE-PRECURSORY BEHAVIOR OF THE GROUND-OBSERVED ULF EMISSIONS:
EXPERIMENTAL RESULTS AND THE SOC-BASED MODELING
Smirnova N.A.1, Troyan V.N.1, Kopytenko Yu.A.2, Uritsky V.M.3, Hayakawa M.4
1 - St.Petersburg State University, St.Petersburg, Russia 2 - SPbFIZMIRAN, St.Petersburg, Russia
3 - CUA at NASA Goddard Space Flight Center, Greenbelt, USA 4 - Institute of Seismo Electromagnetics, Chofu Tokyo, Japan
The ground-observed ULF emissions (f=0.001-1 Hz) are in the most useful electromagnetic frequency range to study the earthquake preparation processes since their skin depths cover the all possible depths of the earthquake hypocenters under the variety types of the crust conductivities. Hear we summarize our experience related to investigation of the preparation stage of strong earthquakes by using the ULF emissions measurements. We show the earthquake- precursory behavior of the ULF emissions both at the short temporal scales (a few hours) and the long scales (a few weeks or months). The effect revealed at the short scales is appearance of the ULF emissions with unusual (in compare with ULF emissions of the magnetospheric origin) polarization ratio – preference of the vertical component over the horizontal one. The effect revealed at the long scales is specific dynamics of the scaling (fractal) characteristics of the ULF emissions – increase of the fractal dimensions of the ULF emissions time series when approaching the date of the earthquake. We present some examples of such precursory behavior and relate them to the corresponding fractal properties of earthquakes. As a summary we suggest the model of the ULF emissions behavior based on the SOC (Self-Organized criticality) theory.
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THE LOWER IONOSPHERE RESPONSE DRIVEN BY THE CHAIN OF THE METEOTSUNAMIS IN THE
MEDITERRANEAN SEA IN JUNE 2014
Solovieva M.1, Rozhnoi A.1, Biagi P.F.2,3, Maggipinto T.2, Levin B.4
1 - Institute of Physics of the Earth, RAS, Moscow, Russia 2 - Department of Physics, University of Bari, Bari, Italy
3 - Inter-Department Centre for the Evaluation and Mitigation of the Volcanic and Seismic Risk, University of Bari, Italy
4 - Institute of marine geology and geophysics FEB RAS, Yuzhno-Sakhalinsk, Russia
The measurements from the very low and low-frequency (VLF/LF) ground based network of stations in the South Europe “The International Network For Frontier Research on Earthquake Precursors” (INFREP) were used to study the response of the lower ionosphere to the meteotsunamis (tsunamis formed under the influence of atmospheric processes) in the Mediterranean Sea. Tsunamis and meteotsunamis have the same periods, same spatial scales and they also generate internal gravity waves (IGWs) propagating upward into the ionosphere where they dissipate and produce perturbations in the plasma density. These perturbations can be detected by electromagnetic waves. A chain of meteotsunamis was observed in the Mediterranean and the Black Sea during 23 - 28 June 2014. These events were caused by a unique synoptic system that traveled above the Mediterranean Sea from Spain to Turkey and into the Black Sea. The system produced sharp atmospheric pressure changes (more than 2 hPa in 5 min), which caused tsunami waves in the open waters of 2-3 cm. The waves traveled in the open sea in different directions and intensified topographically close to the coast. Revealed VLF/LF anomalies coincided in time with meteotsunamis events. The spectral analysis of the anomalous VLF/LF signals revealed periods between 15 and 30 min, coherent with the tsunami. These periods are also in good agreement with the periods of IGWs.
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INFLUENCE OF THE GALACTIC COSMIC RAY ON METEOROLOGICAL PARAMETERS IN THE
STRATOSPHERE
Artamonova I.1,2, Eliseev A.3,4
1 - Main Astronomical Observatory, RAS, St.-Petersburg, Russia 2 - A.I.Voeikov Main Geophysical Observatory, St.-Petersburg,
Russia 3 - A.M.Obukhov Institute of Atmospheric Physics, RAS,
Moscow, Russia 4 - Kazan Federal University, Kazan, Russia
The changes of the meteorological parameters of stratosphere (geopotential height, temperature, zonal and meridional wind components) were analyzed in association with the short-time reduction of the galactic cosmic rays (GCR) intensity, the Forbush decreases. The data provided by the United Kingdom Meteorological Office (UKMO) were used for the period 1991-2004. It was shown that the maxima of variations of all parameters under consideration were observed in the middle and high latitudes of the Northern hemisphere on the pressure level 10 hPa (altitude ~30 km, the height of the maximum ionization of the atmosphere by GCRs) on the 4th-8th days after the event onsets. Significance of deviations was assessed using the Monte-Carlo and False Discovery Rate methods. The minimum energy of galactic cosmic rays precipitating in the regions of revealed disturbances of analyzed stratospheric parameters was estimated.
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LOCAL MAGNETIC FIELDS ON THE MOON AND FORMATION OF LUNAR SURFACE SWIRLS
Divin A.1, Ahmadi T.1, Deca J. 2
1 - St. Petersburg State University, St. Petersburg, Russia 2 - Laboratory for Atmospheric and Space Physics, University of
Colorado Boulder, Boulder, Colorado, USA
Lunar anomaly: Even though the Moon has no global dipolar magnetic field, satellite magnetic field measurements at low-altitude (8-80 km) orbits discovered the presence of patches of intense remanent magnetization of the lunar crust, the so-called Lunar Magnetic Anomalies, LMAs. The origin and the detailed topology of those structure remains unclear and various theories (e.g. due to ancient Lunar magnetic field, or shock magnetization because of meteorite bombardment) exist. Some LMAs are strong enough to stand off impinging solar wind and create a density cavity of a few 10s km above the surface, a minimagnetosphere. We present results of Particle-in-Cell (PIC) simulations of the solar wind - mini magnetosphere interaction. We implement a model of the Lunar magnetic field based on spherical harmonics model presented in the study by [Tsunakawa, 2015] with as high as N=450 spherical harmonic coefficients. 3D PIC simulations indeed display the formation of a minimagnetosphere with complicated magnetic field topology. Particle flux on the surface correlates well with the bright albedo markings, called Lunar swirls. Our simulations provide a convincing evidence that the weathering pattern on the surface is likely to be produced by deflection of the solar wind off the anomaly, but the exact chemical mechanism is yet be identified.
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HIGH-PERFORMANCE COMPUTING IN APPLICATION TO SIMULATIONS OF
MAGNETOSPHERIC PLASMA
Divin A.
St. Petersburg State University, St. Petersburg, Russia
Far above the Earth's atmosphere exists a highly dynamical region of space, called the magnetosphere. Gas is almost fully ionized here, and typical densities are only of the order of a few particles per cubic centimeters. Opposite to the classical gases, charged particles create long-range electromagnetic forces, what determines the two notable properties of plasma: 1) it interacts with electromagnetic field and 2) produces energetic particles and non-Maxwellian distribution functions. From theoretical viewpoint, Vlasov equation should be applied to study the plasma evolution, because the absence of the Local Thermal Equilibrium (LTE) can generate structures in the phase space far different from the equilibrium Maxwellian distribution. In addition, the LTE absence can also act as a source of free energy, which drives certain kinetic processes. Numerically, the phase space adds 1V (2V, 3V) extra dimensions to the 1D (2D, 3D) spatial problem, therefore the amount of resources, needed for a simulation, is significantly increased compared to the fluid MHD treatment. The task is extremely challenging from computational point of view, stressing the need of supercomputing resources. The following basic tenets of high-performance Particle-in-Cell simulations are discussed in this presentation. First we identify sites of activity in the magnetosphere which can be best treated with PIC method. Next an analytical theory of PIC implicit moment method (PIC-IMM) is presented. We briefly discuss the structure of a typical high-performance computing (HPC) facility and present a variety of high-performance PIC simulation applications to the Earth's magnetospheric physics and beyond.
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AUTHORS INDEX
Afremov L.L............................... 123 Akhmerov R.D. .......................... 121 Akimova S.V. ............................. 122 Alexeyev V.N. .............................. 58 Altamore A. .................................. 93 Amelin I.I. .................................. 177 Amirov S.N. ............................... 122 Angelopoulos V. ........................... 64 Anisimov S.V. ............................ 123 Antipov I. ................................... 168 Antonenko V.V. .......................... 121 Aphinogenova N.A. .................... 124 Argunov V.V. .......................222, 226 Artemyev A.V. ....... 84, 105, 114, 118 Artamonova I...............................238 Assinovskaya B. ......................... 214 Astafiev A.M. ............................... 24 Astapenko V. .............................. 188 Avakyan S.V. ...........................26, 27 Baddeley L. .................................. 30 Badyukov D.D. ........................... 126 Baishev D.G. ................................. 90 Barinova V. ................................... 62 Barkhatov N.A. ............... 28, 29, 223 Barkhatova O.M. ........................ 223 Bazhenov M.L. ....................138, 139 Belakhovsky V.B. .............. 30, 31, 85 Belokon V.I. ................................ 125 Berngardt O.I. ............................... 37 Bessarab F.S. ................................ 67 Bezaeva N.S. .............................. 126 Biagi P.F. .................................... 237 Biggin A. .................................... 170 Birulia M.A. ............................... 200 Blyakharchuk T.A....................... 177 Bobrov N.Yu............................... 202 Bobrovnikov S.............................. 62 Bogdanov V.V. ............................ 108 Bol’shakov V.A. ......................... 128
Bol'shakov V.A. ............................ 31 Borchevkina O.P. .................... 32, 72 Boudjada M. ............................... 224 Bricheva S.S. .............................. 189 Bukchin B. .................................. 207 Burnatny S.S. ...................... 129, 158 Chareev D.A. .............................. 126 Chebrov D.V. .............................. 232 Chegis V.V................................... 146 Chen L.-M................................... 180 Cherneva N.V. ............................... 33 Cherniak Iu. .................................. 34 Chernouss S.A. ............................. 36 Chtlpanov M.A. ............................ 37 Chuiko D.A. .................................. 38 Colon D. ...................................... 155 Danukalov K.N. .................. 138, 139 Demekhov A.G. ................. 39, 40, 88 Dement'eva E.V. ...................... 48, 50 Demina I.M. ........................ 130, 131 Denisenko V.V. ...................... 41, 224 Dergachev V.A. ....................... 42, 43 Despirak I.V. ........................... 44, 45 Ditmar P. ..................................... 205 Divin A.V. ................... 119, 239, 240 Dmitriev P.B. ................................ 42 Dolenko S. .................................... 46 Dolenko S.A. ........ 79, 102, 190, 192 Dolotov A.V. ............................... 140 Dovbnya B.V. ................................ 90 Dremukhina L.A. .......................... 57 Druzhin G.I. .................................. 33 Dubyagin S. .................................. 46 Dvorova A.V. .............................. 132 Dyachenko O.I. ........................... 125 Efishov I.I. .................................... 36 Efitorov A. .................................... 46
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Egli R. ........................................ 126 Eliseev A.A. ............................... 206 Elkina D.V. ................................. 133 Eremeev V. ................................... 62 Erkaev N.V. ................. 48, 49, 50, 68 Ermakova E.N. ............................. 51 Evdokimova M.A. ........................ 52 Fabian K. .................................... 151 Fairchild L.M. ............................ 126 Farafonova Yu.G. ........................ 130 Farrugia C.J. ................................. 48 Fedotova O.I. ................................ 99 Fedun V. ..................................... 235 Fedyukin I.V. .............................. 134 Fetisova (Glushkova) N.V. ........... 78 Fetisova A.M. ............................. 135 Filatov M.M. ................................ 36 Filev E.A. ................................... 183 Filinov I.A. ..........................146, 156 Fomochkina A. ........................... 207 Gallet Y. ...............................122, 168 Ganushkina N. .............................. 46 Gaponov V.A. ............................... 53 Gavrilov S.V. .............................. 191 Genevey A. ................................. 168 Gilder S.A. ................................. 155 Gnibidenko Z.N. ......................... 136 Gobarenko V.S. ........................... 208 Golovanova I.V. ...................138, 139 Golovchanskaya I.V. ................54, 68 Gongalskiy B.I. .......................... 180 Gontovaya L.I............................. 198 Gordeev E. .................................... 55 Gorshkov V. ................................ 214 Gorshkova N.V. ...................130, 131 Gravirov V.V. ....................... 209, 211 Grib S.A. ...................................... 56 Gribov S.K. .........................140, 164 Grigorevsky A.V. .......................... 99 Gromov S.V. ................................. 57 Gromova L.I. ................................ 57
Gubin D.I. ................................... 199 Guglielmi A.V. ............................ 210 Guineva V. .................................... 44 Hachay O.A. ............................... 225 Hawkins L. .................................. 170 Hayakawa M. ...................... 227, 236 He K. ........................................... 155 Hramova E.G. .............................. 167 Ievenko I.B. ...................... 36, 58, 59 Iliushin I.G. ................................. 123 Iosifidi A.G. ......................... 141, 165 Isaev I.V. ............................. 190, 192 Ismagilov V.S. ....................... 60, 227 Ivanov I.B. .................................... 68 Ivanov S.A. ................................. 143 Ivanov V.A. ............................. 48, 50 Ivanov V.V .................................. 184 Ivanov Yu.Yu. ............................. 158 Ivonin V.A. .................................. 200 Jicha B.R. .................................... 155 Kaisin А.V. .................................. 108 Kalegaev V.V........................... 61, 62 Kalitenkov N.V. ............................ 36 Karagodin A.V. ............................. 63 Karakhanyan A.K. ...................... 144 Karimov F.H. .............................. 145 Karimov R.R. ........................ 69, 226 Karpinsky V.V. ............................ 211 Karpov A.I. ................................... 32 Karpov I.V. .............................. 32, 72 Karpov M.I. ................................ 230 Kars M. ....................................... 126 Kavtrev S.S. .................................. 53 Kazansky A.Yu. .. 146, 147, 156, 177 Khabarova O.V.............................. 64 Khachay A.Yu ............................. 225 Khachay O.Yu. ............................ 225 Khalipov V.L. .............................. 108 Kharitonov A.L. .................. 191, 193
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Kharitonskii P.V. ..................148, 175 Khazin L.B. ................................ 136 Khazina I.V. ................................ 136 Khidiyatov M.M. ........................ 138 Khrapov B.A. ............................... 92 Kiehas S. ...................................... 64 Kiehas S.A. ................................... 68 Kislov K.V. .......................... 209, 211 Kislov R.A. ................................... 64 Kitaev A.V. ................................. 224 Kleimenova N.G. .....................45, 57 Kletzing C.A................................. 39 Klimenko M.V. ............................. 67 Klimenko V.V. .............................. 67 Klimushkin D.Yu. ....................37, 65 Klyuchkin V.N. ........................... 231 Klyushnikov V.Yu ........................ 66 Kobyakova S.E. .......................... 108 Kolesnikov V.E. ...................195, 200 Kolobov V.V. .............................. 200 Kopytenko Yu.A. ..... 36, 60, 227, 236 Korenkov Yu.N. ............................ 67 Kornilova T.A. .........................54, 68 Koroleva T.Yu. ........................... 212 Korovinskiy D.B. ......................... 68 Korsakov A.A. ............... 69, 109, 226 Korzinova A.S. ....................149, 150 Kosareva L.R. ......................121, 151 Kosolapova N.V.......................... 223 Kosterov A.A. ......................147, 148 Kosterov V.A. ............................. 175 Kotik D.S. ..................................... 51 Kotova G.A. ................................ 108 Kovalev A.A. ................................ 99 Kozelov B.V. ..................... 39, 44, 70 Kozelova T.V. ............................... 70 Kozhevnikov V.M. ..................... 219 Kozlov S.I. ................................... 66 Kozlov V.I. ............................69, 109 Kozlova S.V. ................................. 49 Kozlovskaya E............................ 215 Kozmina L.V. ............................. 124 Krivolutskaya N.A. .................... 180
Krivolutsky A.A. ........................... 71 Krylov P.S. .................................. 121 Krylov S.S................................... 202 Kshevetskii S.P. ............................ 72 Kubyshkina D.I. ............................ 49 Kulakova E.P....................... 152, 181 Kurazhkovskii A.Yu. ................... 177 Kurdyaeva Y.A. ............................. 72 Kuzichev I.V. ................................ 73 Kuzina D.M. ....................... 121, 163 Kuz'mina O.B. ............................ 136 Kuznetsova M. .............................. 55 Lammer H. .................................. 224 Latyshev A.V. .............. 153, 166, 171 Legoff M. .................................... 154 Lemeshko E.Yu. ............................ 80 Leonovich A.S. ............................. 65 Leora S.N. ..................................... 56 Levin B. ...................................... 237 Levin B.V. ................................... 232 Levitin A.E. ................................... 57 Lhuillier F. .................................. 155 Linok A.V. ................................... 196 Liu J. ........................................... 231 Loginov V.A. ............................... 197 Lubnina N.V. ............................... 185 Lukin A.S. ..................................... 75 Lyskova E.L. ............................... 212 Lyubchich A.A. ............................. 45 Mager O.V. .................................... 37 Mager P.N. .............................. 37, 65 Maggipinto T. .............................. 237 .I. ................................................. 172 Malova H.V. .................................. 64 Maltseva O.A. ............................... 76 Malysh E.A. .................................. 33 Malysheva L.M. ............................ 57 Mandrikova O.V. ..................... 77, 78 Manninen J............................ 39, 116 Markov G.P. ........................ 157, 164 Matasova G. ................................ 146
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Matasova G.G. .....................147, 156 Matrosov V.Yu. ........................... 138 Mazur V.A. ................................... 38 Medvedev S.V. ........................... 213 Merkin V. ...................................... 55 Merkur'ev S.A. ........................... 143 Meynadier L. .............................. 179 Mezentsev A.V. .......................48, 50 Mikhailova V.A. ..................141, 165 Minasyan J.O. ............................. 144 Mingalev I.V. ................................ 54 Minyuk P.S. ................................ 129 Mironova I.A. ............................... 63 Mirsayanova E.M. ...................... 153 Mochalov V.A. ............................. 33 Mochalova A.V. ............................ 33 Mokhnatkin A. ............................ 214 Moroz Yu.F. ......... 197, 198, 228, 229 Mukhametdinova L. ..................... 62 Myagkova I. ............................46, 62 Myagkova I.N........................79, 102 Nachasova I.E......................157, 164 Nagorskiy P.M. .................. 66, 80, 81 Nakamura R........................... 84, 118 Namgaladze A.A. ..................82, 230 Naumov A.N........................129, 158 Nemecek Z. .................................. 96 Nevalainen J. .............................. 215 Nguyen M.D. ................................ 62 Nilov M.Yu. ................................ 195 Nishad R.K. ................................ 159 Nourgaliev D.K. ......................... 151 Novikov V.A. .............................. 231 Novikova A.S. ............................ 162 Nurgaliev D.K. ........................... 121 Obornev E.A........................190, 192 Obornev I.E. ........................190, 192 Obridko V.N. .......................104, 167 Ogurtsov M.G. ............................. 113 Okunev V.I.................................. 231 Ovtchinnikov V.M. ..................... 220
Parnikov S.G. ................................ 58 Pasenko A.M. .............................. 160 Pashinin A.Yu. .............................. 86 Pasmanik D.L. .............................. 39 Patil S.K. ..................................... 159 Pavlov A.F. .................................... 99 Pavlov V.E. ................................. 162 Pechersky D.M. .......................... 163 Pershin A.V. .................................. 51 Petersen N. .................................. 155 Petlenko A.V. ................................ 83 Petrova L.N. ................................ 216 Petrukovich A.A.52, 75, 84, 114, 118 Pilipenko O.V. ..................... 157, 164 Pilipenko V.A. ........... 30, 31, 85, 119 Piskarev A.L. .............................. 133 Plotkin V.V. ................................. 199 Polozov Yu.A. ............................... 78 Polyushkina T.N. ..................... 86, 90 Popov V.V. .................................. 165 Popova E.P. ................................... 87 Popova I.V. .................................. 232 Popova T.A. .......................... 88, 101 Potapov A.S. ..................... 86, 89, 90 Powerman V.I. ............................. 166 Pradhan S.K. ............................... 159 Ptitsyna N.G. ............. 91, 92, 93, 107 Pushkar E.A. ................................. 94 Pustovalov K.N. ............................ 81 Raeder J. ....................................... 55 Ragulskaya M.V. ......................... 167 Raita T. ........................................ 116 Rakhmatulin R.A. ................... 86, 90 Reeves G. ...................................... 39 Remenets G.F. ............................... 24 Revunov S.E. ................................ 29 Revunova E.A. .............................. 28 Riabova S.A. ............................... 233 Romanov R.V. ............................... 28 Rozhnoi A. .......................... 235, 237 Rozhnoi A.A. .............................. 232
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Runov A. .................................46, 64 Ruzhin Yu.Ya. ............................. 231 Ryazantsev P.A. ...................195, 200 Rybalko A.A. .............................. 147 Ryzhakova L.V. ............................ 89 Ryzhkov I.I. .................................. 49 Safrankova J. ................................ 96 Sakharov Ya.A. ........................30, 85 Salnaia N. ................................... 168 Samsonov A.A. ........................95, 96 Samsonov S.N. ........................30, 31 Sannikov D.V. .............................. 33 Santolik O. ...............................39, 40 Schaen A.J. ................................. 155 Scherbakova N. .......................... 214 Scholze F. ................................... 135 Sedykh P.A. .............................97, 98 Semakov N.N. .............................. 99 Semenov V.S. .................. 49, 68, 119 Semenova M.P. ........................... 178 Semenova N.V. ........................... 101 Sentemova N.S. .......................... 102 Seredkina A.I. ......................218, 219 Sergeev V. ..................................... 55 Sergeeva M.A. .............................. 76 Sergienko E.S. ............. 148, 165, 175 Shadrina L.P. .............................. 103 Shagimuratov I.I. .......................... 36 Shalimov S.L. .............................. 110 Shatsillo A.V. .......................166, 170 Shcherbakov V.P. 124, 151, 170, 171, 185 Shcherbakova V.V. ...............170, 185 Shchetnikov A.A. ........ 146, 156, 177 Shen X. ....................................... 231 Shennikov A.V. ............................. 51 Shevtsov A.N. ......................195, 200 Shibalova A.S. ............................ 104 Shimelevich M.I. .................190, 192 Shirokyj V.R. .............................. 102 Shklyar D.R. ................................. 73 Shugau Yu..................................... 62
Shustov P.I. ................................. 105 Shvec M.V. .................................... 36 Sibeck D.G. ................................... 96 Sillanpää I. .................................... 46 Simon Q. ..................................... 179 Singer B.S. .................................. 155 Sinha A.K. ................................... 159 Skorokhodov A.A. ...... 195, 200, 201 Smirnov M.A. ..................... 124, 185 Smirnov S. .................................. 214 Smirnov S.E. ....................... 228, 229 Smirnov S.V. ................................. 81 Smirnova N.A. ............................ 236 Smolin S.V. ................................. 106 Smolkin V.F................................. 180 Sokoloff D.D. .............................. 104 Sokolov S.N. ......................... 91, 107 Soldatov V.A. ................ 91, 107, 131 Solovey O.A. .............................. 219 Solovieva M. ....................... 235, 237 Solovieva M.S. ............................ 232 Solyanikov Ya.L. ......................... 172 Song X.-Y. .................................. 180 Spivak A.A. ................................. 233 Srivastava A. ............................... 235 Stanilovskaya Ju.V. ..................... 189 Starchenko S.V. ........... 173, 174, 184 Starodubtsev S.A. ....................... 103 Starunov V.A. .............................. 175 Stepanov A.E. ............................. 108 Swanson-Hysell N.L. .................. 126 Tarabukina L.D. .......................... 109 Tasenko S.V. ................................. 66 Taubenschuss U. ........................... 40 Tepenitsina N.Yu. .......................... 36 Thouveny N. ............................... 179 Tikoo S.M. .................................. 126 Timofeev E.E. ............................. 110 Titov A.V. .................................... 202 Titova A.V. .................................. 178 Titova E.E. .................................... 39 Toth G. ........................................... 55
246
Troyan V.N. ................................ 236 Tsegmed B. ................................... 86 Tselmovich V.A. ..................150, 177 Tsel'movich V.A. ........................ 124 Tsetlin U.B. ................................ 164 Tsirel V.S. ................................... 178 Tsyganenko N. .............................. 55 Tsyganenko N.A. ......................... 112 Tsygankova V.I. .......................... 129 Turyansky V.A. ............................. 70 Tyasto M.I. ................ 42, 91, 92, 107 Ulyahina P.S. .............................. 153 Uritsky V.M. ............................... 236 Usoltseva O. ............................... 215 Usoltseva O.A. ........................... 220 Valet J.P. ..................................... 179 Vallinkoski M.K. ......................... 110 Vardanjants I.L. .......................... 201 Vardanyan K.S. ........................... 203 Vasilev P.A. .................................. 72 Vasiliev S.S. ................................. 43 Vasko I.Y .................................... 105 Vasko I.Y. .............................. 84, 114 Veretenenko S.V. ......................... 113 Veselovskiy R.V.. 135, 152, 153, 170, 171, 180, 181 Vinogradov A.A. ......................... 114 Vinogradov A.B. ........................... 28 Vinogradov E.V. ......................... 181 Vodinchar G.M.............................. 33
Vodovozov V.U. .......................... 186 Vodovozov V.Yu. ........................ 183 Volkov M.A. ............................... 115 Vorobjev V.G. ........................ 29, 115 Wack M. ...................................... 155 Yagodkina O.I. ........ 28, 29, 115, 223 Yahnin A.G. ......51, 88, 101, 116, 117 Yahnina T.A. ......... 51, 101, 116, 117 Yakovleva S.V. .................... 173, 184 Yakovleva V.S. .............................. 81 Yanovskaya T.B. ................. 212, 213 Yegorova T.P. .............................. 208 Yu S.-Y. ....................................... 180 Yukhina N.A. ................................ 87 Yushkov E.V. .............. 105, 114, 118 Yusupova A.R. ............................ 121 Zaitsev I.V. .................................. 119 Zakharenkova I. ............................ 34 Zakharov V.S. ............................. 221 Zalyaev T.L. .................................. 77 Zelenyi L.M. ......................... 84, 114 Zelikson I.S. ................................ 119 Zelinsky N.R. ................................ 57 Zhamaletdinov A.A. ............ 195, 200 Zhidkov G.V. ....................... 170, 185 Zotov O.D. .......................... 120, 210 Zverev A.R. ......................... 183, 186 Zverev V.L. ................................. 115
