Curvilinear Grid Finite-Difference Method to Simulate Seismic Wave Propagation with Topographic Fluid-Solid Interface at Sea Bottom

Abstract:

This paper presents a curvilinear grid finite difference method for modeling seismic wave propagation with topographic fluid (acoustic) and solid (elastic) interface. The curvilinear grid finite difference method has been successfully used for seismic wave simulation with free surface topography and earthquake dynamics with complex falut geometry. For seismic wave simulation with topographic sea bottom, we use the curvilinear grid to conform the grid to the sea bottom to avoid artifical scatterings due to stair-case approximation. We solve the acoustic wave equation in the water layer and the elastic wave equation in the solid below the sea bottom. The fluid-solid interface condition is implemented by decomposing velocity and stress components to normal and parallel directions of the sea bottom. The results exhibit high accuracy by comparsion with analytical solutions for flat interfaces and also work very well when the fluid-solid interface is topographic. The scheme can be easily extended to 3-D situation.