A finite element and finite difference mixed approach for modeling fault rupture and ground motion

We combine a finite element (FE) code, Defmod, and a finite difference (FD) code, OpenSWPC, in modeling fault rupture and resulting ground motion. The rupturing process is modeled by the FE code, while the ground motion is modeled by the FD code. The FE-FD binding follows two steps: First, evaluate the FD grid points motion when executing the FE code; and then, impose those moving grid points to the FD domain to drive wave propagation. In order to avoid performance bottleneck, we implement this FE-FD binding in parallel. To verify this mixed approach, we evaluate two SCEC benchmark problems. The resulting synthetic waveforms agree well with the other benchmark participants. The waveform comparisons suggest that the FE-FD mixed model has less attenuation than the pure FE model.