Coseismic deformation and hierarchical rupture processes of the 2024 Wushi earthquake revealed by Sentinel-1 InSAR and gradient techniques

On January 23, 2024, an M W 7.0 earthquake struck Wushi County, Xinjiang, China, near the boundary between the Tianshan Orogen and the Tarim Basin. To resolve the source geometry and surface rupture features, we employed differential interferometric SAR (DInSAR) using both ascending and descending Sentinel-1 data. Inversion of the coseismic deformation fields reveals that the rupture occurred on a northwest-dipping thrust fault with a strike of 225.6° and a dip angle of 67.3°. To enhance the detection of shallow fracturing, we applied a phase gradient stacking technique, which successfully delineated distributed surface ruptures—including several off-fault features—that are not discernible in conventional unwrapped interferograms. These linear anomalies exhibit variable orientations and clustering patterns, suggesting complex near-surface strain partitioning. Furthermore, Coulomb stress modeling based on the inverted slip distribution indicates stress loading exceeding +5 MPa along the northeastern Maidan–Shayilamu fault, implying increased postseismic hazard, while a stress shadow is identified to the southwest. This study demonstrates the effectiveness of integrating InSAR deformation analysis, phase gradient enhancement, and stress transfer modeling in characterizing oblique-thrust faulting and near-field ground response. Our results provide new constraints on rupture behavior in transpressional settings and contribute to seismic hazard assessment in the active intracontinental orogenic zone of the southern Tianshan.