Modern problems and prospects for the development of magnetotelluric monitoring on the territory of the Bishkek geodynamic test site

Abstract

The high sensitivity of the electromagnetic parameters of the geological environment to the influence of geodynamic processes for the territory of the Bishkek geodynamic test site is shown. An assessment of the characteristics of the stress-strain state of the geological environment and the behavior of variations in electromagnetic parameters has been carried out in order to identify patterns in their relationship for seismically active regions of the Tien Shan. The promising objects for monitoring observations are identified and the results obtained are presented. The experimental results obtained indicate that the position of the regions of stable correlation (clusters) on the polar correlation diagrams is associated with the geoelectric structure of the observation point and corresponds to the orientation of the main tectonic elements in the vicinity of this point. A detailed geological and geophysical interpretation of geoelectric sections was carried out in order to separate modern active faults and weakened zones of the Earth’s crust, for example, the Kochkor basin. The relationship between the manifestation of geoelectric inhomogeneities and the spatial distribution of the epicenters of seismic events is revealed; it is shown that a significant part of earthquake epicenters is confined to structural inhomogeneities of the Earth’s crust; the depths of the geoelectric section, most sensitive to the influence of geodynamic processes, have been determined. The behavior of variations in the electrical conductivity of the earth‘s crust in a wide range of periods has been investigated according to the data of profile magnetotelluric soundings (MTS) at the Kentor geophysical monitoring minipolygon. Field experiments confirm the concept of the relationship between the stress-strain state of the medium and the change in apparent resistivity through the redistribution of saline solutions between fracture systems. The problems and trends in the development of magnetotelluric monitoring of modern geodynamic processes in the Northern Tien Shan are shown. To solve the tasks set, a methodology for conducting monitoring studies is proposed, which most fully takes into account the specific features of the deep structure and distribution of seismicity of the Bishkek geodynamic test site.