Dynamic Rupture Process of the 2025 Mw 7.1 Dingri, Tibet, Earthquake: Insights into the Role of Fault Geometry and Stress Heterogeneity

Abstract The 2025 Mw 7.1 Dingri earthquake provides a rare opportunity to investigate the dynamic rupture behavior of a normal fault within the South Tibetan rift system. In this study, we perform three-dimensional (3D) dynamic rupture simulations using the spectral element method to investigate the complex rupture process along the Dingmucuo fault. Our model incorporates a 3D curved fault with the initial slip distribution parameterized via a Bayesian von Karman approach. The simulation successfully reproduces the observed Interferometric Synthetic Aperture Radar coseismic deformation, capturing a predominantly unilateral northward-propagating rupture with a rupture duration of ∼25 s. We find that an asymmetric initial stress distribution controls rupture directivity, arresting brief southward propagation. Additionally, the geometric bend in the northwestern segment acts as a critical geometric barrier, inducing localized stress concentrations where slip rate reaches ∼1.0 m/s. These simulated dynamic processes are spatially consistent with the observed localized surface ruptures and the heterogeneous distribution of aftershock clusters. Our findings highlight the profound impact of complex fault geometry and initial stress heterogeneity on the dynamic evolution of normal-faulting earthquakes, with implications for seismic hazard assessment in the Shenzha-Dingjie rift.