An absorbing boundary algorithm for diffusive-viscous wave equation

A new absorbing boundary method for diffusive-viscous wave equation (DVW) is proposed to deal with the artificial reflections from boundaries caused by a truncated computational domain in seismic wave numerical modeling. The main idea is to make the seismic waves exponentially attenuate with propagation distance by adding a proper absorbing layer around the boundary of computational domain. The solution of the wave equation in infinite homogenous space is obtained by using Fourier transform. Then, auxiliary equations are constructed by introducing decay functions such that the solution of auxiliary equations is the solution of the DVW equation in computational domain and decays exponentially at boundaries. The wave equation is finally solved by using finite-difference method in both homogeneous media and homogeneous layered media. Numerical results are given through comparison of the results from the proposed method and those of non-absorbing boundary condition, and show that boundary reflections are absorbed with the proposed method. The proposed method is also applicable to acoustic equation and Stokes equation.