Affiliation:
1. Institute of the Earth’s Crust, Siberian Branch of the Russian Academy of Sciences
2. Geological Institute, Siberian Branch of the Russian Academy of Sciences
Abstract
Studies have been conducted on the variations of ambient noise recorded by broadband and short-period seismic stations in the area of South Baikal before and after the large December 9, 2020 Kudara earthquake with Mw = 5.6. 10 days before the earthquake, there was a gradual increase of oscillation amplitudes in the frequency range from 0.01 to 0.1 Hz, with an increasing background observed also during 4 days after the main shock (period from 01.12.2020 to 13.01.2021). The maximum amplitude increase is 19.5 against the background. During this time, there were recorded 48 aftershocks. The analysis of direction of particle motion in seismic waves over the reporting period showed an abrupt change in the orientation of oscillations, which is fully consistent with the azimuth for the main shock epicenter. The analysis of seismograms over the next period (from December 13) did not show similar effects in the ambient noise field. Apparently, the ambient noise field reflected the process of slow faulting before the earthquake and after the main shock with subsequent attenuation.
Publisher
The Russian Academy of Sciences
Reference14 articles.
1. Saltykov V.A. On the Possibility of Using the Tidal Modulation of Seismic Waves for Forecasting Earthquakes // Izvestiya, Physics of the Solid Earth. 2017. V. 53. № 2. P. 250–261.
2. Sobolev G.A. Microseismic Variations Prior to a Strong Earthquake // Izvestiya, Physics of the Solid Earth. 2004. V. 40. № 6. P. 455–464.
3. Sobolev G.A., Lyubushin A.A., Zakrzhevskaya N.A. Asymmetrical Pulses, the Periodicity and Synchronization of Low Frequency Microseisms // Journal of Volcanology and Seismology. 2008. V. 2. P. 118–134.
4. Любушин А.А. Сейсмическая катастрофа в Японии 11 марта 2011 г.: долгосрочный прогноз по низкочастотным микросейсмам // Геофизические процессы и биосфера. 2011. Т. 10. № 1. С. 9–35
5. Соболев Г.А. Концепция предсказуемости землетрясений на основе динамики сейсмичности при триггерном воздействии. М.: Изд-во ИФЗ РАН, 2011. 56 с.