Abstract: The M_S6.4 earthquake occurred in Yutian County, Xinjiang, China on June 26, 2020. In this paper, the Sentinel-1A/B satellite’s ascending and descending SAR data are collected to extract the coseismic deformation field of this earthquake by using InSAR technology. Constrained by the coseismic deformation field, the geometric parameters of the seismogenic fault are obtained by using the uniform sliding model of Bayesian method. Finally, Steepest Decent Method (SDM) is used to determine the more delicate distribution of the fault. The results show that the deformation field of InSAR is mainly distributed along the North-North-East direction, with a span of about 40 km in the East-West direction and 30 km in the South-North direction. The deformation features are subsidence in the West and uplift in the East, with the maximum subsidence of about 200 mm in the West and the maximum uplift in the East of about 70 mm. The fault originated from the Yutian earthquake is a concealed fault with strike of 187.68°, dip angle of 59.78°and slip angle of 77.76°. The macro focal depth of Yutian earthquake is about 6.29 km, and the moment magnitude is M_W6.19. The fault slip distribution is mainly concentrated in the region of 7~12 km along the strike and 4~11 km along the trend, with the average slip momentum of about 0.2m and the maximum slip momentum of about 0.97 m at 7~8 km along the trend. The coseismic dislocation is mainly manifested as positive fault motion.

Key words: The 2020 Yutian M_S6.4 earthquake, InSAR, Coseismic deformation, Slip distribution, Focal mechanism