Accurate simulations of nonlinear dynamic shear ruptures on pre-existing faults in 3D elastic solids with dual-pairing SBP methods

Abstract: In this paper we derive and analyse efficient and stable numerical methods for accurate numerical simulations of nonlinear dynamic shear ruptures on non-planar faults embedded in 3D elastic solids using dual-paring (DP) summation by parts (SBP) finite difference (FD) methods. Specifically, for nonlinear dynamic earthquake ruptures, we demonstrate that the DP SBP FD operators [K. Mattsson. J. Comput. Phys., 335:283-310, 2017] generate spurious catastrophic high frequency wave modes that do not diminish with mesh refinement. Meanwhile our new dispersion relation preserving (DRP) SBP FD operators [C. Williams and K Duru, arXiv:2110.04957, 2021] have more accurate numerical dispersion relation properties and do not support poisonous spurious high frequency wave modes. Numerical simulations are performed in 3D with geometrically complex fault surfaces verifying the efficacy of the method. Our method accurately reproduces community developed dynamic rupture benchmark problems, proposed by Southern California Earthquake Center, with less computational effort than standard methods based on traditional SBP FD operators.