Simulation seismic wave propagation in topographic structures using asymmetric staggered grids

A new 3D finite-difference(FD) method of spatially asymmetric staggered grids was presented to simulate elastic wave propagation in topographic structures.The method approximated the first-order elastic wave equations by irregular grids finite difference operator with second-order time precise and fourth-order spatial precise.Additional introduced finite difference formula solved the asymmetric problem arisen in non-uniform staggered grid scheme.The method had no interpolation between the fine and coarse grids.All grids were computed at the same spatial iteration.Complicated geometrical structures like rough submarine interface,fault and nonplanar interfaces were treated with fine irregular grids.Theoretical analysis and numerical simulations show that this method saves considerable memory and computing time,at the same time,has satisfactory stability and accuracy.