Dynamic Rupture and Ground Motion Simulations of Potential Earthquake on the Tianzhu Seismic Gap

The Tianzhu seismic gap is an important segment of the Haiyuan fault system. In recent decades, earthquakes have occurred on most fault segments within this region, whereas the Jinqianghe–Maomaoshan fault has not experienced a major earthquake for an extended period. Given that this fault segment is widely regarded as having elevated potential seismic hazard, we conduct three-dimensional dynamic rupture and strong ground motion simulations using the curved grid finite difference method.To effectively constrain model input parameters, interseismic locking coefficients and slip deficit distributions inverted from InSAR and GPS observations are used to impose physically based constraints on the heterogeneous initial stress conditions along the fault. Simulation results indicate that the spatial distribution of locked regions plays a critical role in controlling rupture extent. Under locking-constrained conditions, scenario earthquakes with moment magnitudes of Mw 7.3–7.4 and maximum slip of approximately 5.5 m are generated. Further analyses show that larger accumulated slip deficits tend to promote higher earthquake magnitudes, whereas the surface seismic intensity does not exhibit a monotonic response to slip deficit.These results suggest that the Jinqianghe–Maomaoshan fault segment may be associated with elevated potential seismic hazard.