Motorcycle: A spectral boundary-integral method for seismic cycles on multiple faults

Numerical simulations of seismic cycles constitute a useful tool to test the implications of various constitutive friction laws, materials properties, and boundary conditions. A unique challenge of numerical models of fault dynamics is the resolution of a wide range of time and length scales, going from milliseconds during seismic ruptures to years during seismic quiescence with a rupture front spanning a few meters to fault slip distributed over multiple kilometers. A well-suited approach for this problem is the boundary integral method, as the elastic medium is captured by appropriate Green's functions, and only the fault interface must be sampled numerically, resulting in orders of magnitude reduction in computational burden, while still allowing realistic fault geometry. Using the spectral boundary integral method reduces the numerical complexity even further, allowing the exploration of increasingly complex rheological models. This package provides a suite of numerical modeling software to simulate seismic cycles on multiple parallel faults combining the efficiency of Fourier methods and the complexity of an interacting fault network.