SPATIAL AND TEMPORAL DYNAMICS OF THE SUBSOIL RADON FIELD IN THE WEST FERGHANA REGION BEFORE AND AFTER THE NAZARBEK (TASHKENT) EARTHQUAKES OF 1980-1981

Abstract

The seismic activity of Central Asia, which include the West Ferghana region, is directly governed by the development of the T'yan-Shan mountain system. It has been shown that synchronous changes in the subsoil radon field, reflecting changes in the stress-strain state of the above mountain system, were observed at all stations in the Central Asian test area. We analyze these changes based on monitoring of subsoil radon over the course of 14 months at two stations in the area. Based on the results of this study, we treat the T'yan-Shan orogenic belt as a generator of tectonic deformations, whose fronts, propagating toward the interior of the Turanian Block, become an apparent cause of the earthquakes that occur there.