Research of Focal Mechanism and Focal Depth of Qilian, QinghaiM_s5.2 Earthquake

Abstract

This paper selects the waveform records of 16 broadband digital seismic stations in the regional seismic network of Gansu province, Qinghai province, and Sichuan province involved inversion, use CAP focal mechanism solution method to calculate the Ms 5.2 earthquake which occurred in Qilian County, Qinghai Province, November 23, 2015. Obtained the focal mechanism solution of this earthquake is a strike-slip fault with thrust property. The inversion results show the optimal double couple solution is nodal plane I: The strike is 112°, the dip, 51.7°; and the rake, 24.5°. Nodal plane II: The strike is 7°, the dip, 71°; and the rake, 139°. Earthquake moment magnitude is Mw5.2 and the optimal depth solution is 8km, which is consistent with the results of IGP-CEA. We calculate focal depth with the arrival time difference between sPn and Pn phases, the results is 6.6km, which agree with the CAP method results and verify the feasibility of this method.