HR: 1340h
AN: S33B-1308    [Abstracts]
TI: Possibility Of The Electromagnetic Earthquake Precursor Source Localization
AU: * Dudkin, F
EM: fd@isr.lviv.ua
AF: Lviv Centre of Institute of Space Research, 5-A Naukova St., Lviv, 79000, Ukraine
AU: Korepanov, V
EM: vakor@isr.lviv.ua
AF: Lviv Centre of Institute of Space Research, 5-A Naukova St., Lviv, 79000, Ukraine
AU: Hayakawa, M
EM: hayakawa@whistler.ee.uec.ac.jp
AF: The University of Electro-Communications, Department of Electronic Engineering, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
AU: Arora, B
EM: arorabr@wihg.res.in
AF: Wadia Institute of Himalayan Geology, 33, General Mahadeo Singh Road, Dehra Dun, 288 001, India
AB: The existence of earthquake electromagnetic (EM) precursors is permanently discussed by the scientific community and there is no generally accepted opinion about their origin. A wide instrumentation array at California does not reveal any EM precursors of several recently occurred earthquakes (EQ), whereas rather simple set of magnetometers and/or electrometers in India, Greece, Japan very often reliably detected them. So, it appears that these precursors are very different in their peculiarities and they vary not only at diverse places but also for different times even at the same place. Apparently this depends on the specifics of geological formation in seismically active zones. This report is an attempt to explain some experimental facts with observed seismogenic ULF emissions. The possible phenomenological model of such diversity is discussed and some conditions of precursory signal detection are outlined. The approach to the determination of the EQ precursory EM signals source location is proposed based on multi-points observations of ULF electromagnetic signals in the monitored area. The main principle of the following data processing is based on the assumption that at relatively small distance between future EQ epicenter and observation points (no more than ~ 200 km), we are always in near zone of electromagnetic wave propagation what allows us to use as informative carrier signal amplitude only. This peculiarity can be used for enhancing the signal-to-noise ratio by processing simultaneously the synchronously collected signals at several observation points. One recent example of the EQ precursory EM signals detection in India, Koyna region, is discussed in details. It is shown that the obtained results fit rather well with previous theoretical modelling and the study of EM signal parameters (amplitude, polarization) allows us to simulate possible geological structure in the EQ epicenter which can generate the signals with observed parameters. In the conclusion, the critical requirements to the field observation system for electric and magnetic parameters monitoring in the seismically active regions are presented. The example of practical realization is given: the design features of the automated ULF observation system LEMI-30 with large dynamic range and satellite synchronization of signals sampling are discussed and the example of its practical realization is shown. This study is supported by STCU grant 3165.
DE: 0925 Magnetic and electrical methods (5109)
DE: 0994 Instruments and techniques
DE: 7215 Earthquake source observations (1240)
DE: 7223 Earthquake interaction, forecasting, and prediction (1217, 1242)
SC: Seismology [S]
MN: 2007 Fall Meeting