The Bystrinskoe Earthquake in the Southern Baikal Region (21 September 2020, Mw=5.4): Main Parameters, Precursors, and Accompanying Effects

We present the preliminary results of a study of the Bystrinskoe earthquake, which occurred in the southern Baikal region on 21 September 2020 and was accompanied by shaking with an intensity of VI-VII on the MSK-64 scale in the epicentral area and with an intensity of V in large cities of southern East Siberia (Irkutsk, Angarsk, Usolye-Sibirskoe, Zakamensk, etc.). A preliminary characteristic of the seismic event is given on the basis of a comprehensive analysis of seismological, structural-tectonic, strain, emanation, and hydro-geochemical data obtained during the monitoring of hazardous geologic processes in the Baikal natural territory. We have estimated the seismologic parameters of the Bystrinskoe earthquake, characterized the accompanying phenomena, and identified the effects that are of interest as probable precursors of future strong earthquakes in the Baikal region. The data obtained suggest that the earthquake occurred in the zone of the Main Sayan Fault as a result of strike-slip movement along the W-NW fault. The earthquake focus was apparently located at a shallow depth, as evidenced by the duration of the shocks, macroseismic manifestations, and the strong rumble heard at different directions from the epicenter.

Automated summary

The preliminary study of the Bystrinskoe earthquake in the Baikal region provides insight into the seismic activity in the area and suggests that future strong earthquakes in the region may have precursors that can be identified through comprehensive analysis of various geologic processes. The earthquake is believed to have occurred along the Main Sayan Fault due to strike-slip movement along the W-NW fault, with the epicenter located at a shallow depth.