Abstract: On September 5, 2022, an M_S6.8 earthquake occurred in Luding County, Ganzi Tibetan Autonomous Prefecture, Sichuan Province. In this study, we analyzed regional seismic data and inverted the focal rupture process of the main shock. The results show that the seismic fault of this earthquake is the Xianshuihe fault of generally left-lateral strike-slip. The rupture propagated primarily in the SSE direction along the fault strike, expanding from the initial rupture point to the shallow part. The duration of the entire process was approximately 13 s, releasing a scalar seismic moment of 1.2×10¹⁹ N·m, equivalent to M_W6.6. The rupture had a length of about 18 km and a width of 14 km, with a maximum coseismic slip of 2.7 m and an estimated centroid depth of 6.2 km. Comparing our inversion results with those obtained from teleseismic waveform data, we conclude that the main rupture area of this earthquake is located on the SSE side of the epicenter, while no obvious rupture area is observed on the NNW side of the epicenter.

Key words: The 2022 Luding M_S6.8 earthquake, Source rupture process, Waveform inversion, Coseismic slip