Optimal Absorbing Boundary Conditions For Finite Difference Modeling Of Acoustic And Elastic Wave Propagation
Name
1993.10 Peng_Toksoz.pdf
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854.87 KB
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3e022563d1224083ac79e10b630a1225
Author(s)
Peng, Chengbin
Toksoz, M. N.
Date Issued
1993
Publisher
Massachusetts Institute of Technology. Earth Resources Laboratory
Series/Report no.
Earth Resources Laboratory Industry Consortia Annual Report;1993-10
Abstract
An optimal absorbing boundary condition is designed to model acoustic and elastic wave
propagation in 2D and 3D media using the finite difference method. In our method,
extrapolation on the artificial boundaries of a finite difference domain is expressed as
a linear combination of wave fields at previous time steps and/or interior grids. The
acoustic and elastic reflection coefficients from the artificial boundaries are derived.
They are found to be identical with the transfer functions of two cascaded systems: one
is the inverse of a causal system and the other is an anticausal system. This method
makes use of the zeros and poles of reflection coefficients in a complex plane. The
optimal absorbing boundary condition designed in this paper yields about 10 dB smaller
in magnitude of reflection coefficients than Higdon's absorbing boundary condition, and
around 20 dB smaller than Reynolds' absorbing boundary condition. This conclusion is
supported by a simulation of elastic wave propagation in a 3D medium on an nCUBE
parallel computer.
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