Haibing Li, Jiawei Pan, Marie‐Luce Chevalier, Dongliang Liu, Shiguang Wang, Heng Luo, Long Zhang, Lihua Fang, Teng Wang, Fucai Liu, Shenqiang Chen, Xiaohui He, Xunzhang Zhu, Yihu Zhang, Qiong Wu, Chunrui Li
Abstract Large, shallow earthquakes typically produce surface ruptures, whereas aftershocks rarely do. Here, we document a rare case in which the 2024 Mw 7.0 Wushi earthquake (western China) did not rupture the surface, but a Mw 5.7 aftershock did. Integrated field observations, satellite imagery, interferometric synthetic aperture radar (InSAR) data, and relocated seismicity reveal that the aftershock reactivated shallow back- and fore-thrusts, forming a pop-up structure with clear surface breaks. This event demonstrates that aftershocks can generate significant surface deformation by reactivating pre-existing shallow faults—a process not commonly accounted for in seismic hazard assessments. Our findings emphasize the need to incorporate secondary shallow faults into hazard models, especially in complex fold-and-thrust systems.