A comparative analysis of continuum plasticity, viscoplasticity and phase-field models for earthquake sequence modeling

Abstract This paper discusses continuum models for simulating earthquake sequences on faults governed by rate-and-state dependent friction. Through detailed numerical analysis of a conventional strike-slip fault, new observations regarding the use various are presented. We update recently proposed plasticity-based model using consistently linearized formulation, show its agreement with discrete fault thicknesses hundreds meters, and demonstrate mesh objectivity slip-related variables. To obtain fully regularized width description an internal length scale, we study performance convergence complemented Kelvin viscosity term phase-field approach to cohesive fracture. The viscoplasticity-based can introduce scale mesh-objective response. However, grid sizes down this only holds very high viscosities that inhibit seismic slip rates, which renders impractical sequences. On other hand, our implementation provides numerically robust framework agrees reference solution, is objective, reaches rates. model, unsurprisingly, requires highly refined grids around zones reproduce results close model. Following line, effect parameter predictions discussed.