Physics-Based Scenario Earthquake Simulations of the Kashi Fault: From Dynamic Rupture to Strong Ground Motion Prediction

The physics-based numerical simulation of scenario earthquakes has become a vital and rapidly developing research direction in modern seismology. This advanced numerical approach enables quantitative evaluation of potential seismic hazards and can produce critical ground-motion outputs, including peak ground velocity (PGV), peak ground acceleration (PGA), and synthetic seismic waveforms, providing fundamental data for urban earthquake disaster analysis and hazard assessment. In this work, a robust hybrid numerical framework is constructed by coupling the discontinuous Galerkin (DG) method for spontaneous dynamic fault rupture simulation with the curvilinear-grid finite difference method for high-precision seismic wave propagation. This study targets the Kashi Fault, a major active tectonic structure located beneath the densely populated urban area of Kashi, China. The numerical model fully incorporates realistic fault geometric characteristics, 3D subsurface velocity structures, and complex topographic variations to implement urban-scale scenario earthquake simulations. Sensitivity analyses of key rupture parameters are conducted to establish a reasonable earthquake source model. Accordingly, spatial distributions of PGV, PGA, and seismic intensity over the Kashi region are obtained. The simulated results can provide reliable theoretical references for regional seismic hazard evaluation and urban seismic disaster assessment in high-risk areas of Kashi.