Abstract: On May 12, 2008, the great Wenchuan earthquake occurred on the Longmenshan belt, which is located at the eastern margin of the Tibetan Plateau, rupturing the Beichuan-Yingxiu and Guanxian-Jiangyou faults. We apply Yabuki&Matsu’ura’s inversion method to estimate the co-seismic slip distribution of thhis earthquake from GPS data. The whole fault model is divided into four sub-faults during our inversion. Our results show that the slips caused by the great earthquake are characterized mainly by thrust motion near Yingxiu, the south segment of the Yingxiu-Beichuan fault; the dextral components are apparently larger than thrust slips at the north segment of the fault. Our estimations agree well with the results of geologic survey and the characteristics of rupturing. The estimated slips have two high-slip concentrations up to 9.6 m and 9.3 m, located respectively near the Yingxiu town and Beichuan city, which suffered the greatest fatalities and structure damages during the earthquake. The total moment released by the great earthquake is about 8.07×10²⁰ N·m, corresponding to an earthquake with magnitude of M_W7.9. Our study shows that Yabuki&Matsu’ura’s inversion method is suitable to estimate the fault slip model in mainland China.

Key words: Yabuki&Matsu’ura’s inversion method, GPS data;Wenchuan earthquake, Planar fault segments