Rw. Graves, SIMULATING SEISMIC-WAVE PROPAGATION IN 3D ELASTIC MEDIA USING STAGGERED-GRID FINITE-DIFFERENCES, Bulletin of the Seismological Society of America, 86(4), 1996, pp. 1091-1106
This article provides an overview of the application of the staggered-
grid finite-difference technique to model wave propagation problems in
3D elastic media. In addition to presenting generalized, discrete rep
resentations of the differential equations of motion using the stagger
ed-grid approach, we also provide detailed formulations that describe
the incorporation of moment-tenser sources, the implementation of a st
able and accurate representation of a planar free-surface boundary for
3D models, and the derivation and implementation of an approximate te
chnique to model spatially variable anelastic attenuation within time-
domain finite-difference computations. The comparison of results obtai
ned using the staggered-grid technique with those obtained using a fre
quency-wavenumber algorithm shows excellent agreement between the two
methods for a variety of models. In addition, this article also introd
uces a memory optimization procedure that allows large-scale 3D finite
-difference problems to be computed on a conventional, single-processo
r desktop workstation. With this technique, model storage is accommoda
ted using both external (hard-disk) and internal (core) memory. To red
uce system overhead, a cascaded time update procedure is utilized to m
aximize the number of computations performed between I/O operations. T
his formulation greatly expands the applicability of the 3D finite-dif
ference technique by providing an efficient and practical algorithm fo
r implementation on commonly available workstation platforms.