EVOLUTION OF “NARYN” GEOELECTRIC CROSS-SECTIONS AND COMPARISON WITH EARTHQUAKE DISTRIBUTION IN HISTORICAL PERSPECTIVE

The “NARYN” geoelectric model, which runs along the 76° E meridian through the Central Tien Shan from the Kazakh Shield to the Tarim Platform, is one of the longest cross-sections in continental Asia. This paper provides a historical overview of geoelectric models based on magnetotelluric (MT) soundings from 1999-2000 and 2005. Two inversion models constructed from these data using different algorithms are presented: the discrete-smoothed NARYN-RLM model and the piecewise continuous NARYN-INV2D model. A local earthquake catalog for 1980­2022 is considered. Hypocenter distributions from four regional and global seismic catalogs are superimposed on a reference cross-section to re-examine the previously identified relationship between crustal conductivity and earthquake depth distribution. It is noted that weak seismicity is mainly concentrated above the upper boundary of the middle and lower crustal conductor, while the strongest events are grouped in resistive, consolidated blocks of the earth’s crust or at their contacts with conductive zones.

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