Nonreflecting Boundary Conditions for Elastodynamic Scattering

An exact nonreflecting boundary condition was derived previously for timedependent elastic waves in three space dimensions [SIAM J. Appl. Math.60, 803 (2000)]. It is local in time, nonlocal on the artificial boundary, and involves only first derivatives of the displacement. Here it is shown how to combine that boundary condition with finite difference and finite element methods. Stability issues are discussed. Numerical examples with a finite difference method demonstrate the high improvement in accuracy over standard methods.