Abstract:Using gCAP method based on waveform data of digital seismic network, we study the focal mechanism solution of 2020-01-23 Shiqu MS4.3 earthquake in Sichuan province. The result shows that strike/dip/slip of nodal plane Ⅰ are 134°/82°/11° and those of nodal plane Ⅱ are 42°/79°/171°, the centroid depth is 9 km and the moment magnitude is MW4.53. The crustal velocity structure, positioning error and data quality are analyzed to test the stability and reliability of the focal mechanism solution. The results show that these factors have little influence on the inversion results. The aftershock sequences are extended along a NW direction, located in the northeast area of main shock, dipping to northeast. According to geological structure characteristics of the source region, the focal mechanism solution of main shock and space distribution of aftershock sequences, we conclude that nodal plane Ⅰ is inferred to the fault plane and the seismogenic fault is Changshagongma fault. The Shiqu MS4.3 earthquake is a left-lateral strike-slip earthquake event.
YANG Yanming,HU Bo,DAI Yong et al. Research on Focal Mechanism and Seismogenic Structure of 2020-01-23 Shiqu MS4.3 Earthquake in Sichuan Province[J]. jgg, 2021, 41(2): 167-172.