2D acoustic‐elastic coupled modeling using the cell‐based finite‐difference method

Abstract

To describe wave propagation in fluid‐solid environment that is usually encountered in marine seismic exploration, we need a simple but accurate 2D modeling algorithm in the time domain. We design the acoustic‐elastic coupled modeling algorithm based on the cell‐based method, which has proven to give accurate solutions for Lamb's problem in elastic media. The cell‐based method delineates stress‐free conditions at the free surface just with the changes of material properties, which indicates that it will also properly deal with the subsurface interfaces. In the acoustic‐elastic coupled modeling, we first compose finite differences individually for the acoustic and elastic media, and then combine the differences with the fluid‐solid interface boundary condition. Numerical experiments show that the cell‐based coupled modeling algorithm gives solutions compatible with analytic solutions, and properly describes converted waves as well as reflections. We expect that our 2D algorithm can be straightforward applied to 3D problems.