Elastic Wave Simulation Beyond Conventional Courant-Friedrichs-Lewy Stability Limit by Variable Length Staggered-Grid Finite-Difference

Abstract

Summary The traditional elastic finite-difference (FD) simulation methods are confined by conventional Courant–Friedrichs–Lewy (CFL) stability limit, which imposes an upper limit on the simulation efficiency. In order to simulate the elastic wave propagation beyond the stability bottleneck, we develop an elastic variable-length temporal and spatial operators’ method, which includes two major aspects. First, a new elastic FD stencil is incorporated into our modelling strategy by generalizing existing decoupled elastic temporal and spatial high-order FD scheme. Second, an adaptive variable-length operators’ method is developed to ensure modelling accuracy and stability constraints locally rather than globally. These combined strategies make elastic wave extrapolation beyond conventional CFL stability limit feasible and accurate. Numerical examples validate the stability superiority of the new elastic modelling method over traditional ones.