Tectonic Deformations and Subsequent Seismic Events in the Southwestern Flank of the Baikal Rift System Based on GPS Data

The measurement data obtained at the GPS network in the southwestern part of the Baikal Rift System for the period from 1994 to 2020 were analyzed. The spatial relationship between seismic events and tectonic strain rates was estimated. The field of modern horizontal motions and deformations was calculated for the Tunka, South Baikal, and Khubsugul depressions. The rotation pole of the Siberian block was defined. The general geodynamic setting on the western flank of the Baikal Rift System is characterized by low horizontal velocities in the range of 0.5–1.4 mm yr–1. Based on calculation of the relative deformations, the contrast zones of dilatation with narrow zones with the “non-Baikal” type of directions of deformation processes against the background tectonic extension regimes have been determined for the first time in the Bystraya and Khubsugul tectonic depression. Tectonic stresses are accumulated in these narrow zones and released in earthquakes.