Moderate Earthquakes (M = 4.1–4.8) in 2011–2019 in the Area of the Goloustnaya River Delta (Southern Baikal Region): A Detailed Analysis.

Radziminovich, Ya. B.; Filippova, A. I.; Melnikova, V. I.; Gileva, N. A.

In this paper we consider four moderate earthquakes that occurred on November 9, 2011; September 5, 2015; March 16, 2018; and October 10, 2019, in the southern basin of Baikal Lake near the Goloustnaya River delta. Seismotectonically, the earthquake sources are confined to the southwestern part of the Olkhon graben. The 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 earthquake 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. In 2011–2019, these earthquakes caused a noticeable macroseismic effect within the Irkutsk agglomeration, as well as a rather wide public response. Macroseismic data were collected mainly using an online survey system; the number of responses received within the first day after an earthquake varies from 127 to 341. The maximum intensity, IV–V, was observed for the November 9, 2011 earthquake in the settlement of Bolshoye Goloustnoye. The results can be used for assessing the seismic hazard in the Southern Baikal region.

IRKUTSK (Russia); EARTHQUAKES; WATERSHEDS; NUMBER systems; INTERNET surveys; EARTHQUAKE aftershocks

Izvestiya, Atmospheric & Oceanic Physics, 2023, Vol 59, Issue 11, p1587

0001-4338

Academic Journal

10.1134/S0001433823100079