Abstract：Based on the three-component broadband waveform data and seismic phase reports from the digital seismic networks in Sichuan, Guizhou and Chongqing, we use Geiger positioning method and ISOLA method to relocate the Changning MS6.0 earthquake sequence and invert the focal mechanism of five MS≥5.0 earthquakes in the sequence. The relocation results show that the earthquake sequence is mainly distributed in the axis of Baixiangyan-Shizitan anticline, along the direction of 65°NW. Along this direction, the focal depth features are deep in the northwest and shallow in the southeast. Inversion results of focal mechanism show that the rupture of main shock is characterized by high dip angle and sinistral strike-slip. The strike/dip/rake of nodal plane Ⅰ is 20°/72°/151°, the strike/dip/rake of nodal plane Ⅱ is 120°/62°/21°, which is basically consistent with the axial strike of Baixiangyan-Shizitan anticline. The content of pure double-couple(DC) of the five earthquakes is less than 70%, and the centroid depth is less than 10 km. Comprehensive analysis shows that the seismogenic fault of Changning MS6.0 earthquake is a sinistral strike-slip fault developed in Baixiangyan-Shizitan anticline. We speculate that the Changning earthquake was caused by fluid injection and complex geological structure activities.
