High-order finite-difference seismic forward modeling method for fluid-solid boundary coupling media

This paper proposes a novel and stable forward modeling method, which can describe the wave propagation through fluid-solid coupled media. Firstly, we deduce the seismic wave equations of fluid-solid coupled media with irregular interface of seabed utilizing the cubic-spline quantitative method based on the continuity of stress and displacement of the interface. And then, the high-order differential scheme for spatial differentiation is introduced into the method above, which can improve the spatial accuracy of numerical simulation. Furthermore, we also suppress the time discretization that reduces the numerical dispersion by transforming the fourth-order time differential into higher-order spatial differential method. Finally, comparing with results of the scalar wave equation and numerical simulation, we analyze the numerical results of the method proposed in this paper for a simple horizontal layered model and a complex one. The numerical simulation of wave propagation in the fluid-solid coupled media indicates that the method proposed in this paper is convenient and accurate.