Uncovering potential cascading earthquakes in northeastern Tibet

Abstract Conventional assessments of earthquake cascading rely on geometric plausibility criteria but lack physical realism of rupture interactions. Here, we propose a physics-based approach by integrating interseismic fault coupling and accumulated seismic moment as on-fault prestress constraints into dynamic rupture simulations, and apply it to the Tianzhu and Gulang seismic gaps in northeastern Tibet. The results reveal diverse cascading scenarios (Mw 6.3‒7.8), including multi- and whole-fault ruptures of the Tianzhu gap, and partial ruptures involving both gaps. While whole rupture of both gaps is not produced, possibilities exist with elevated on-fault stress. The occurrence and extent of cascading ruptures are far more complex than judged by surface fault geometry (step-over and bend) alone, but are controlled by the interplay among fault geometry, rupture directionality, dynamic stress triggering, and stress or strength heterogeneities. The integration of fault kinematics and dynamic rupture simulations provides a physics-based practice for improving seismic hazard assessment.