Bulletin of the Seismological Society of America; June 2003; v. 93; no. 3;
p. 1198-1211; DOI: 10.1785/0120000027
© 2003 Seismological Society of America
Stability Analysis of Finite-Difference Approximations of Elastic Wave Equations
Richard Stacey
Department of Electrical, Electronic and Information
Engineering
City University
Northampton Square
London EC1V ØHB
U.K.
In this article we develop new and very general techniques for the analysis
of the stability properties of finite-difference approximations of elastic
wave equations, as used in solids and liquids. It is shown that if certain
common conditions are satisfied, then the time dependence of every
permitted grid mode in any of these formulations can be related to a
single time-independent eigenvalue. It is further shown that only a few
(generally two or three) modes are relevant to stability and that for these
modes the values of the time-independent eigenvalue can be determined by
simple numerical experiments. These results permit a simple and thorough
analysis of stability to be undertaken, both as a preliminary to making
measurements using a particular formulation and as a means of comparing
different formulations. The analysis is validated, and its application is
demonstrated using two examples, taken from a new twin-grid formulation for
the solidliquid interface and from the Composed Approximation for a
solid free surface.
Copyright © 2003 by the Seismological Society of America.