Kudara Earthquake of September 12, 2020 (MW = 5.5) on Lake Baikal: Results of Instrumental and Macroseismic Observations

The article discusses the results of processing instrumental and macroseismic observations of the strongest earthquake in Central Baikal in the last 60 years, which occurred on December 9, 2020 (M_W = 5.5), as well as its aftershocks. The event was named the Kudara earthquake, after the locality where the maximum intensity of shocks was recorded. The epicenter of the main shock is confined to Proval Bay (Lake Baikal), which formed as a result of the catastrophic Tsagan earthquake of 1862. The sufficiently high density of seismic stations in the region allowed us to obtain reliable estimates of the position of epicenters and source depths for the main shock and aftershocks. In total, more than 70 earthquakes were recorded, located within an area extending in the sublatitudinal direction. The strongest aftershock (K_R = 12.6) occurred to the west of the main source on the first day after the main shock. To estimate the seismic moment and focal spectrum of the earthquake, the coda envelope inversion method was tested. The moment magnitudes for the main shock and three aftershocks have been obtained.