Institute of Computational Mathematics and Mathematical Geophysics SB RAS

International Conference on Mathematical Methods in Geophysics «MMG-2008»

Akademgorodok, Novosibirsk, Russia, October 13-15, 2008

Abstracts

Mathematical Simulation in Geophysical Problems. Electromagnetic Methods

From modeling on specimens by acoustic emission method towards analysis of induced seismicity including electrotriggering effects

Bogomolov L.M., Borovsky B.V., Gavrilov V.A. , German K. A., Zakupin A.S. (1), Sychev V.N., Sychev I.V.

Research Station of RAS in Bishkek city,
Institute of Volcanology and seismology FEB RAS,
Altai-Sayan Branch of GS SB RAS

The effect of activation of acoustic emission from loaded rocks samples, due to pulsed electromagnetic field impacts has been revealed vy research groups of UIPE RAS, UIHT RAS, RS RAS. The effect may be considered as a fundamental to explain the reason why seismicity is influenced by electromagnetic fields of natural (magnetic storms with abrupt beginning) and man-made (electromagnetic soundings with the use of geophysical MHD-generators) origin. For further analysis of electrostimulating effect scaling and its role in earthquakes occurrence the new data on interrelations between variations of electromagnetic fields and seismicity is to be helpful. This information has been obtained at Bishkek geodynamic test site (RS RAS) during trial active seismoelectromagnetic monitoring. Currently, the electric sounding generator (ESG) is used at RS RAS for deep electromagnetic soundings. There were regimes of ESG power on in 2000 -2005, for which the energy influx to the crust exceeded that for the case of MHD runs. The analysis of diurnal distributions of North Tien Shan seismicity recorded by KNET digital telemetric network has elicited a fact that electric impacts of ESG give rise to some increment of microseismicity in 5-10 days after power action (similarly to the effect of MHD generators). This may be relevant to partial relaxation of nonuniform overstress in geological medium. An important evidence of correlation between electromagnetic variations and that of crust destruction on some meters scale of length (intermediate scale compared with typical laboratory and natural objects size) is the results obtained at IVS FEB RAS. The results involve the synchronization of diurnal changes in natural electromagnetic field and in intensity of geoacoustic emission measured in deep borehole by sensitive geophone.In the future the information on given external impacts may be applicable for specification of seismic zoning, particularly in the complicated cases. The response to external actions means to point out the clastering sites, where natural earthquakes themselves are the most probable.

Note. Abstracts are published in author's edition

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