Geophysical processes and biosphere: article

Аnnotation: In this paper, we consider four moderate earthquakes – November 9, 2011, September 5, 2015, March 16, 2018, and October 10, 2019, – occurred in the southern basin of Baikal Lake near the Goloustnaya river delta. Seismotectonically, the earthquake sources are confined to the southwest-ern part of the Olkhon graben. The obtained earthquake focal mechanisms allow us to suggest the activity of local submeridional faults, feathering the structures of the general northeast strike. For two seismic events, the following parameters were determined: scalar seismic moment M0 = 4.0·1015 N·m, moment magnitude Mw = 4.4, and source depth h = 12 km for the September 5, 2015 earth-quake and M0 = 2.2·1015 N·m, Mw = 4.2, and h = 7 km for the March 16, 2018 earthquake. None of the seismic events was followed by noticeable aftershock activity. The considered earthquakes in 2011–2019 caused noticeable macroseismic effect within the Irkutsk agglomeration, as well as a ra-ther wide public outcry. Macroseismic data were collected using mainly an online survey system; a number of responses, received during the first day after an earthquake, varies from 127 to 341. Max-imum intensity – IV–V – was observed for the November 9, 2011 earthquake in Bolshoye Goloust-noye settlement. The obtained results can be used for seismic hazard assessments in the territory of the settlements in the Southern Baikal region.