3D Elastic Wave Modeling Using Hybrid Absorbing Boundary Condition and Global Optimal Implicit Finite-difference Scheme

The artificial boundary reflections are caused by the limited computational domain of numerically modeling wave propagation. And the numerical dispersion is the consequence of discreting computational domain. These two issues are hot topics for numerical modeling. In this paper, we generalize the hybrid absorbing boundary condition based on the 1st order one-way wave equations for modeling 3D elastic wave propagation. Compared to the conventional split-PML absorbing boundary condition, the new 3D absorbing boundary condition has the advantages of small computational cost, easy implementation and significant absorption. On the other hand, we utilize the global optimal implicit staggered-grid finite-difference scheme based on least-squares (global OISGFD) for modeling 3D elastic wave propagation. Compared to the conventional Taylor-expansion method, the global OISGFD scheme can achieve the same accuracy with shorter operator stencil, thus it is more efficient. Synthetic examples of a homogeneous model and the 3D SEG/EAGE slat model demonstrate the merits of our new 3D elastic wave modeling strategy.