Peridynamic modeling for fault rupture dynamics

Fault rupture is a complex process involving the evolution of fault geometry, multi-physics coupling mechanisms, phase transformations and others. Compared with analytical approaches, numerical methods have proven to be a more viable alternative for analyzing fault rupture. In recent years, peridynamics (PD) has shown particular promise in studying fracture evolution and has been successfully applied to hydraulic fracturing and seepage processes in geological materials. In this study, we propose a PD modeling framework for simulating instability nucleation processes along mature fault interfaces. To address the complex mechanical behavior of internal fault interfaces under coupled prestress and dynamic friction, we developed a PD-based boundary condition treatment. This approach does not rely on traditional empirical assumptions, such as “stress release” or “slip to the maximum static friction”. Instead, it self-consistently updates the interfacial geometry, deformation, and force density distribution by rigorously tracking the actual kinematic state of the material points. Utilizing the Southern California Earthquake Center benchmark framework, we rigorously simulated the slip-weakening nucleation process, demonstrating the feasibility of applying PD to seismic rupture analysis. Strain analysis and comparisons between finite and small-strain approximations all confirm the applicability of small-strain theory in prior studies. Based on these insights, we also conducted systematic parametric studies examining the model’s non-local characteristics and convergence behavior by varying both the horizon radius and discretization scale. This model shows strong potential for addressing complex geophysical rupture processes.