Abstract: This study utilized teleseismic data to invert and analyze the rupture process of the 2023 Jishishan M6.2 earthquake in Gansu, China. The causative fault of the earthquake was likely to be a previously unclear local fault, the Jishishan eastern margin fault. The results indicated that the earthquake rupture lasted approximately 8 s, with a primary rupture length of 20~25 km and a width of about 25 km. On the nodal plane Ⅰ with a strike of 164°, the entire rupture process released a scalar seismic moment of 1.46×10¹⁸ N·m, equivalent to a moment magnitude of M_W6.05 with a maximum coseismic slip of 0.25 m. The estimated centroid depth was 9.5 km and the rupture primarily extended in the south-southeast direction along the fault strike. On the nodal plane Ⅱ with a strike of 303°, the scalar seismic moment released was 1.38×10¹⁸ N·m, equivalent to a moment magnitude of M_W6.03, with a maximum coseismic slip of 0.19 m and a centroid depth of 11.1 km. The rupture exhibited a bilateral pattern, predominantly extending in the southeast direction, with a northwestward expansion trend.

Key words: The 2023 Jishishan M6.2 earthquake, Source rupture process, Waveform inversion, Coseismic slip