Variable Grid Finite-Difference Modeling Including Surface Topography

Abstract

We have developed a two-dimensional viscoelastic finite-difference modeling method for highly complex topography. Realistic modeling of seismic wave propagation in the near surface is complicated by many factors, such as strong heterogeneity, topographic relief and large attenuation. In order to account for these complications, we use a velocity-stress staggered grid and employ an 0(2,4) accurate viscoelastic finite-difference scheme. The implementation includes an irregular free surface condition for topographic relief and a variable grid technique in the shallow parts of the model. Numerical tests indicate that approximately ten grid-points per shortest wavelength results in accurate calculations. The method is accurate and stable, and allows us to handle complex structure in finite-difference modeling.