Coseismic and Postseismic Displacements of the 2024 Mw 7.0 Wushi, China, Earthquake Observed from SAR Images

Abstract On 23 January 2024, a magnitude (Mw) 7.0 earthquake struck Wushi County (China) in the southwestern Tian Shan orogen. Both Sentinel-1 and Advanced Land Observation Satellite-2 radar images were used to obtain coseismic displacements with interferometry and pixel offset-tracking techniques. We calculated coseismic 3D displacements with a prevailing strain model and variance component estimation method and then inverted the source model of this earthquake. The results reveal a high-angle (58°) thrust fault with a significant strike-slip component. The maximum slip of 3.3 m is concentrated at 13 km depth, and the estimated seismic moment is 4.01×1019 N·m, equivalent to an Mw 7.04 event. The postseismic slip inverted from 10-month Interferometric Synthetic Aperture Radar displacements exhibits a spatial pattern complementary to the coseismic slip, suggesting that the coseismic rupture was likely inhibited by rate-strengthening zones. Integrated analysis of inter-, co-, and postseismic geodetic data further reinforces the evidence that the southwestern Tian Shan region is characterized by slip partitioning, with ongoing compression and left-lateral motion in the intermontane areas.