Numerical acoustic-elastic coupling and curved boundaries for RTM
Highly optimized finite difference (FD) tools are widely used for imaging tools like the reverse time migration (RTM). These tools only gain full speed if they operate on a cube-shaped domain. In this work, we propose a weighted matched interface and boundary (wMIB) method for FD schemes for acoustic and elastic wave equations. This method can be used to accomodate more intricate boundary conditions. As it operates between the FD update steps, the optimized FD kernels can be applied without modification. We show how moderately curved boundaries can be treated with an additional extrapolation step. Finally, the applicability is demonstrated in an acoustic benchmark with a curved boundary, as well as a coupled acoustic/elastic benchmark computation.