Focal Mechanism Solutions and Seismogenic Structure of M≥4.7 Earthquakes Since 2014 in Yongshan, Yunnan

By using the Cut-And-Paste(CAP) inversion method and the HypoDD method, this paper presents the focal mechanism solutions for 3 M≥4.7 earthquakes and the relocated earthquake sequence information in Yongshan region on the basis of broadband seismic wave records from Sichuan and Yunnan digital seismic network. The results of 3 earthquakes show that the focal mechanism solution type of M5.3 earthquake on April 5, 2014 is thrust. The focal mechanism solution types of M5.0 earthquake on August 17, 2014 and M4.7 earthquake on May 16, 2019 are strike-slip. Combining with the regional seismotectonic analyzing and the spatial distribution of seismic epicenter and seismic intensity for the 3 earthquakes, the main seismogenic structure of the 3 earthquakes and aftershocks is an anonymous fault located between the Lianfeng-Zhaotong fault and Ebian-Jinyang fault, or the frontal blind fault of the Lianfeng-Zhaotong fault.