Bulletin of the Seismological Society of America; June 2004; v. 94; no. 3;
p. 1002-1015; DOI: 10.1785/0120030103
© 2004 Seismological Society of America
A Multidomain PSTD Method for 3D Elastic Wave Equations
Yan Qing Zeng* and
Qing Huo Liu
Department of Electrical and Computer Engineering
Duke University
Durham, North Carolina 27708
A 3D multidomain pseudospectral time-domain method is developed for elastic
wave equations. The method is based on the spectral derivative operator
approximated by Chebyshev or Lagrange polynomials. Unlike the Fourier method
that assumes periodic boundary conditions, the Chebyshev pseudospectral method
allows for the incorporation of various boundary conditions (such as the free
surface boundary condition) into the numerical scheme. In this multidomain
scheme, the computational domain is decomposed into a set of subdomains
conformal to the problem geometry. Each curved subdomain is then mapped onto a
cube in the curvilinear coordinates so that a tensor-product Chebyshev grid
can be utilized without the staircasing error. An unsplit-field perfectly
matched layer is developed as the absorbing boundary condition. Numerical
examples show that this scheme is efficient for simulating elastic waves
phenomena in the presence of complex objects. The method is found to be
significantly more efficient than the finite-difference time-domain method in
terms of memory and run-time requirements.
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