Deformation Patterns and Rupture Mechanisms of the Longitudinal Valley Fault in Eastern Taiwan: Insights From Three‐Dimensional Discrete Element Modeling

Abstract

Active faults exhibit complex geometric features, with rupture processes controlled by the coupled effects of tectonic loading, fault geometry, and internal displacement heterogeneity. To elucidate the interrelationship between long‐term deformation, stress redistribution, and rupture evolution, we constructed a three‐dimensional numerical model of the Longitudinal Valley Fault (LVF) in eastern Taiwan using the discrete element method (DEM). The model simulates heterogeneous displacement, rupture sequences, and energy release under long term quasi‐static tectonic loading. Model results show spatially heterogeneous rupture and cumulative deformation. Rupture in the late stage concentrates mainly on the eastern side and in the central and northern sections of the fault. Cumulative displacement follows a non‐monotonic pattern with depth, characterized by shallow discrete adjustment, a continuous intermediate depth deformation band, and overall weakening with localized high displacement patches at greater depths. Along strike, high displacement zones and rupture clusters are spatially associated with local bends and rapid strike variations, suggesting that geometric complexity may influence the spatial organization of heterogeneous deformation. Results of stress partitioning further indicate that stronger normal confinement at depth may limits the development of a continuous deep high displacement band. These results provide mechanical constraints for identifying candidate regions with enhanced deformation concentration and rupture susceptibility, guiding further investigation of potential rupture prone zones.