N-Times Absorbing Boundary Conditions for Compact Finite-Difference Modeling of Acoustic and Elastic Wave Propagation in the 2D TI Medium

Abstract

This article presents decoupling n-times absorbing boundary conditions designed to model acoustic and elastic wave propagation in a 2D transversely iso- tropic (TI) medium. More general n-times boundary conditions with absorbing pa- rameters are also obtained by cascading first-order differential operators with param- eters. These boundary conditions are approximated with simple finite-difference schemes for numerical simulations. The numerical results show that the absorbing for the reflection waves strengthens with increasing the absorbing times n and the discretization boundary formulas are stable. Specially, the n-times absorbing bound- ary condition with absorbing parameters is better than that without the absorbing parameters under the case of same absorbing order. Elastic wave fields and three- component synthetic seismograms, generated by using the compact finite-difference and the decoupling n-times absorbing boundary, also illustrate that the n-times ab- sorbing boundary condition can eliminate effectively the spurious numerical reflec- tions in the acoustic and elastic wave modeling for the TI medium case.