He X J,Zhang X D,Meng L Y,Wang Y. 2023. Spatio-temporal relationship between source parameters such as stress drop and significant earthquakes in Changning-Xingwen area. Acta Seismologica Sinica,45(2):271−284. doi: 10.11939/jass.20210196
Citation: He X J,Zhang X D,Meng L Y,Wang Y. 2023. Spatio-temporal relationship between source parameters such as stress drop and significant earthquakes in Changning-Xingwen area. Acta Seismologica Sinica,45(2):271−284. doi: 10.11939/jass.20210196

Spatio-temporal relationship between source parameters such as stress drop and significant earthquakes in Changning-Xingwen area

  • A MS6.0 earthquake with a focal depth of 16 km occurred with the epicenter of (28.34°N, 104.90°E) in Changning county, Yibin city, Sichuan Province on June 17, 2019. There were three strong aftershocks above MS5.0 within five days after the Changning earthquake and another MS5.6 earthquake occurred in Gongxian County on July 4. This paper relocated 1948 ML≥2.0 earthquakes in Changning-Xingwen area during 2019 to 2020 by the double difference method based on the seismic phase observation report provided by China Earthquake Networks Center. The distribution of 1 823 earthquakes above ML2.0 after relocation shows that the aftershock sequence in the northern area of Changning spreads along the NW−SE direction anticline. Moreover, the earthquakes in southern area is more scattered. We calculated source parameters such as seismic moment and stress drop based on 208 earthquakes above ML3.0 in Changning-Xingwen area, Sichuan from 17 June 2019 to 31 December 2020, and analyzed the evolution characteristics of seismic stress drop in the region before and after the Changning MS6.0 earthquake on June 17, 2019. The results show that the stress drop of ML3.0−3.9 earthquakes significantly increased in Changning-Xingwen area before the moderate strong aftershocks, and most of the earthquakes above ML4.0 occurred in the high stress drop area of ML3.0−3.9 earthquakes in the study area.
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