Interplay of Coseismic Rupture, Afterslip, and Aftershocks Associated with the 2024 Mw 7.1 Wushi Earthquake

The Mw 7.1 earthquake occurred in Wushi County on 22 January 2024, representing the largest earthquake in the southern Tianshan Orogen for more than a century. Together with two subsequent strong aftershocks, this sequence allows us to examine the geometry of the complex fault system and interactions of seismic and aseismic slip. Using InSAR observations, we resolved the coseismic and postseismic deformation to constrain the slip distributions associated with the earthquake sequence. The results show that the mainshock ruptured a northwest-dipping fault, with coseismic slip mainly concentrated at depths of 10–30 km and peaking at approximately 2.7 m near 16 km, releasing a geodetic moment of 4.9 × 1019 N·m (Mw 7.1). The 2024 Mw 5.7 aftershock ruptured a surface-reaching fault with a peak slip of approximately 1 m at approximately 2 km depth, whereas the 2025 Mw 5.8 aftershock ruptured a nearby blind fault at depths of 5–10 km. Afterslip during the first six months occurred predominantly on the mainshock fault, and was largely complementary to the large coseismic slip zone. The cumulative geodetic moment released by the ~six-month afterslip was estimated to be 5 × 1018 N·m, equivalent to approximately 10.2% of the mainshock moment. The Coulomb stress analysis shows that the mainshock produced positive stress changes of approximately 1.6 bar and approximately 2.6 bar at the hypocenters of the Mw 5.7 and Mw 5.8 aftershocks, respectively, bringing both faults closer to failure. In addition, positive stress changes induced by postseismic afterslip on the Mw 5.8 fault indicate that time-dependent stress redistribution further promoted its failure. These results reveal the spatial and temporal partitioning of seismic and aseismic slip within a multi-fault system and highlight the importance of integrating coseismic rupture, postseismic afterslip, and stress-transfer processes to better assess postseismic seismic hazard in continental thrust regions.