The December 9, 2020, Mw 5.5 Kudara earthquake (Middle Baikal, Russia): internet questionnaire hard test and macroseismic data analysis

Abstract

The article discusses the macroseismic data on the December 9, 2020, M w 5.5 Kudara earthquake which occurred in the Selenga River delta (Middle Baikal, Eastern Siberia, Russia). This is the strongest seismic event in the study area over a 50-year period. The bulk of macroseismic data was obtained with internet questionnaire posted on the website of the Baikal Branch of the Geophysical Survey of the Russian Academy of Sciences. In total, 1433 responses were received from 120 places (villages, towns and cities) in Eastern Siberia, with most of them was obtained from large cities. In addition, a field survey was carried out in the near-field, which revealed slight non-structural damage to buildings in several settlements. The maximum intensity assessed VI–VII MSK-64 or VI EMS-98 was observed in the Kudara village. Taking into account the macroseismic data obtained, we have prepared a map of intensity data points. The largely observed shakings (intensity IV MSK-64/EMS-98) were noted at epicentral distances of over 500 km; intensity II MSK-64/EMS-98 was noted at a distance of up to 980 km. The Kudara earthquake allowed us to test the internet questionnaire in real conditions of strong seismic impact. The results obtained confirm the rather high efficiency of the internet questionnaire in the conditions of the Baikal region, however, some limitations associated with the responses spatial distribution are exist. A detailed study of the Kudara earthquake allowed us to gain new experience useful for the further development of macroseismology in Eastern Siberia.

The Ml 5.5, 5 February 2022 Earthquake Near the Oil and Gas Field on the Shelf of Northeastern Sakhalin Island

“…Методика оценки сейсмической интенсивности по откликам населения через интернет [43,48] широко используется во всем мире [28,29,31,32,42]. На протяжении последних пяти лет данная методика тестировалась на о. Сахалин [11,36] и показала свою эффективность в оперативной оценке макросейсмической обстановки.…”