A nonreflecting boundary condition for discrete acoustic and elastic wave equations

Geophysics - Tập 50 Số 4 - Trang 705-708 - 1985
C. Cerjan1, Dan Kosloff2, Ronnie Kosloff3, Moshe Reshef2
1Lawrence Livermore National Laboratory, P.O. Box 808 L502, Livermore, CA 92550
2Department of Geophysics and Planetary Sciences, Tel‐Aviv University, Tel‐Aviv 69978, Israel; and The Seismic Acoustics Laboratory, University of Houston, Houston, TX 77004
3Department of Physical Chemistry, and the Fritz Haber Research Center For Molecular Dynamics, The Hebrew University, Jerusalem 91904, Israel

Tóm tắt

One of the nagging problems which arises in application of discrete solution methods for wave‐propagation calculations is the presence of reflections or wraparound from the boundaries of the numerical mesh. These undesired events eventually override the actual seismic signals which propagate in the modeled region. The solution to avoiding boundary effects used to be to enlarge the numerical mesh, thus delaying the side reflections and wraparound longer than the range of times involved in the modeling. Obviously this solution considerably increases the expense of computation. More recently, nonreflecting boundary conditions were introduced for the finite‐difference method (Clayton and Enquist, 1977; Reynolds, 1978). These boundary conditions are based on replacing the wave equation in the boundary region by one‐way wave equations which do not permit energy to propagate from the boundaries into the numerical mesh. This approach has been relatively successful, except that its effectiveness degrades for events which impinge on the boundaries at shallow angles. It is also not clear how to apply this type of boundary condition to global discrete methods such as the Fourier method for which all grid points are coupled.

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Geophysics

Tập 50 Số 4

705-708

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