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

This article presents decoupling n-times absorbing boundary conditions designed to model acoustic and elastic wave propagation in a 2D transversely isotropic (TI) medium. More general n-times boundary conditions with absorbing parameters are also obtained by cascading first-order differential operators with parameters. 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 boundary condition with absorbing parameters is better than that without the absorbing parameters under the case of same absorbing order. Elastic wave fields and threecomponent synthetic seismograms, generated by using the compact finite-difference and the decoupling n-times absorbing boundary, also illustrate that the n-times absorbing boundary condition can eliminate effectively the spurious numerical reflections in the acoustic and elastic wave modeling for the TI medium case.