St. Petersburg State University St. Petersburg Branch of the EurAsian Geophysical Society 10th International Conference \PROBLEMS OF GEOCOSMOS" Book of Abstracts St. Petersburg, Petrodvorets, October 6{10, 2014 Supported by Russian Foundation of Basic Research St. Petersburg 2014 Programme Committee Prof. V. N. Troyan Chairman, St.Petersburg University Prof. H. K. Biernat Space Research Institute, Austria Dr. N. V. Erkaev Institute of Computational Modelling SB RAS, Russia Prof. M. Hayakawa University of Electro-Com- munications, Tokyo, Japan Prof. B. M. Kashtan St.Petersburg University Prof. Yu. A. Kopytenko SPbF IZMIRAN, Russia Prof. A. A. Kovtun St.Petersburg University Dr. I. N. Petrov St.Petersburg University Prof. V. S. Semenov St.Petersburg University Prof. V. A. Sergeev St.Petersburg University Dr. N. A. Smirnova St.Petersburg University Dr. N. A. Tsyganenko St.Petersburg University Dr. E. Turunen Sodankyl¨aGeophysical Observatory, Finland Dr. I. G. Usoskin University of Oulu, Finland Prof. T. B. Yanovskaya St.Petersburg University Organizing Committee S. V. Apatenkov N. Yu. Bobrov V. V. Karpinsky A. A. Kosterov M. V. Kholeva M. V. Kubyshkina T. A. Kudryavtseva E. L. Lyskova N. P. Legenkova I. A. Mironova A. A. Samsonov E. S. Sergienko R. V. Smirnova ISBN 978-5-98340-334-5 Contents Section C. Conductivity of the Earth . 5 Section P. Paleomagnetism and Rock Magnetism . 34 Section S. Seismology . 84 Section SEMP. Seismo-ElectroMagnetic Phenomena . 106 Section STP. Solar-Terrestrial Physics . 125 Author index . 215 3 4 Section C. Conductivity of the Earth Geoelectrical and geothermal models of the Pripyat Trough Astapenko, V.N. (State Enterprise \RPCG", Minsk, Belarus), Lev- ashkevich, V.G.(National Academy of Sciences of Belarus) and Logvi- nov, I.M.( Institute of Geophysics NAS of Ukraine, Kiev, Ukraine) Pripyat Trough is a part of regional Palaeozoic { Phanerozoics Pripyat { Dnieper { Donets Palaeorift. The EUROBRIDGE'96 and EURO- BRIDGE'97 profiles crosses the Pripyat Trough. Along this profiles seismic, geoelectrical and heat models of crust and upper mantle are compared. Complex interpretation allows to narrow a collection of alternative models and explains a nature of geophysical anoma- lies. Anomalous areas of conduction in the upper crust are in accor- dance with isotherms of 180{200◦C. Anomalies in the lower crust are correlated with temperatures exceeding 450◦C and connected with fluids which are separated from number of minerals. The Pripyat Trough is characterized by contrast heat field which values range from 40 mW/m2 in the south part to 70 mW/m2 in the north part of trough. The results of two-dimensional inversion of generalized curves of magnetotelluric soundings, which are situated on profile EURO- BRIDGE'97 are shown. Existence of a conductive layer at depths exceeding 20 km is confirmed in large parts of profile. In the north part of the Pripyat Trough the resistance of upper mantle at depths of 60{100 km is lesser than 20 Ohm·m. Possible reason of anomaly is a presence of amphibolite in the mantle, as far as this region is expected to be a zone of the collision of palaeoproterozoic segments of the crust: Fennoscandia and Sarmatia. Physical scale modeling of TEM soundings using commercial Tcikl equipment Bobrov, N.Yu., Krylov, S.S., Mironov, A.A., Titov, A.V. (St.Peters- burg State University, St.Petersburg, Russia) Physical modeling was carried out to evaluate the potential of tran- sient electromagnetic soundings to unseal the peculiarities of saline- 5 dome tectonics. Two types of electromagnetic arrays were investi- gated: inductive excitement Qq array with rectangular loop as a transmitter and conductive excitement AMNB array. The simulated geoelectric structure was as follows: well conductive sedimentary cover overlaying resistive basement with salt formations of different size and shape penetrating sediments at bottom boundary. Measurements with inductive array were made at aluminium full scale metal models with scaling factor 1:100000. Modeling of TEM sound- ings with AMNB array was carried out with scaling factor 1:10000 in electrolithic tank of size 4:4.5 m. Sedimentary cover was simulated by saturated NaCl solution, models of invaded salt formations were fabricated of concrete. Commercially available Tcikl system was used for all experiments. At metal models the equipment was used as is without any modification. For measurements in the tank a separate generator with short pulse edge was applied and some improvements were made in the receiving channel to ensure possibility of measuring E-component of transient signal at short (mks) delays. Valuable results have been obtained demonstrating effectiveness of AMNB array for detecting shape and size of salt domes. The distribution of electrical conductivity in the depths of the North Dobrudga and PeriDobrudga depression Burakhovych, T.K., Kushnir, A.N. (Geophysical Institute of NAS of Ukraine, Kiev, Ukraine) Our work is dedicated to the search for the interrelation between conductivity anomalies in the Earth's crust and upper mantle and foci of seismic events that have occurred on the territory of PeriDobrudga and North Dobrudga. Based on the results of experimental MT and MVP investigation, regions of anomalously low magnitudes of electric resistivity (ρ) were found and 3D geoelectric models of the Earth crust and upper mantle. The velocity structure features of the mantle beneath Peridobrudga depression and its surroundings make a strong possibility to identify the preconditions of the mantle seismicity associated with the signs of mantle plumes (super-deep fluids) in the lower and middle mantle. 6 Three-dimensional deep geoelectric model built on results of mod- ern MTS and MVP methods reflects inhomogeneous distribution of electric conductivity in the depth on the territory of PeriDobrudga depression and North Dobrudga. Anomalies of high electric conduc- tivity from the surface of the Earth crust to the upper mantle are identified. Stretched for hundreds of kilometers conductors are as- sociated with deep conductive fractures of different ranks and with their intersections: Frunze, Saratsky, Bolgrad, Cahul-Izmail, Chadyr- lungsk fractures and others. A highly conductive layer is identified on the southern side of PeriDobrudga depression which lies at the depth corresponding to the lower crust and the top part of upper mantle. North side of PeriDobrudga depression is characterized by the distribution of electrical conductivity in the upper mantle which is the same as that of EEP, while presence of conductive structure at the depths of 110 to 160 km differs the southern slope from the northern one. Without a doubt, there is a relationship between seismicity and geo- electric parameters that reflects the current state of the Earth's in- terior. The origin of high electric conductivity anomalies may be the result of geodynamic processes on the boundaries of regions charac- terized by various manifestations of these processes. Earthquake sources as well as anomalies of high electric conductivity are mainly correlated with active deep tectonic fractures and juncture zones of geological structures such as different age zones of Precam- brian EEP and Cimmerian Scythian plate on the territory of Peri- Dobrudga depression and North Dobrudga. Elaboration of a complex algorithm of neural network solu- tion of the inverse problem of electrical prospecting based on data classification Dolenko, S.A., Isaev, I.V., Persiantsev, I.G. (D.V. Skobeltsyn Insti- tute of Nuclear Physics, M.V. Lomonosov Moscow State University, Moscow, Russia); Obornev, I.E., Obornev, E.A., Shimelevich, M.I. (S. Ordjonikidze Russian State Geological Prospecting University, Moscow, Russia) Solution of the inverse problem (IP) of electrical prospecting is the process of construction of an operator mapping the vector of com- ponents of electromagnetic fields measured on the Earth's surface to 7 the distribution of electrical conductivity in the studied underground area. As actual distributions are usually quite complex, their ad- equate description requires a large number of parameters, reaching several hundred even for the 2D-case. So this IP is a complicated high-dimensional ill-posed problem with a well-known instability. To describe the sought distribution of the electrical conductivity, dif- ferent 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 studied data pattern, resulting in the selection of the most appropriate parameterization scheme. In their previous studies, the authors considered the solution of the IP of magnetotelluric sounding (MTS) using artificial neural networks (ANN) (perceptrons). Also, it was demonstrated that the described classification problem can be successfully solved by ANN with av- erage rate of correct determination of the parameterization scheme exceeding 97%. Since then, the authors have elaborated a novel method of ANN-based solution of the MTS IP within scheme G0, based on simultaneous determination of a group of several parameters at once. Optimal conditions