Bulletin of the Seismological Society of America; February 1989; v. 79; no. 1;
p. 113-126
© 1989 Seismological Society of America
Pulse propagation in random media by a causal approach
ABRAHAM I. BELTZER,
JOANNE WEGNER,
BERNARD R. TITTMAN and
JAMES B. HADDOW
CENTER FOR TECHNOLOGICAL EDUCATION HOLON AFFILIATED WITH TEL-AVIV UNIVERSITY, P.O.B. 305, HOLON 58102, Israel
DEPARTMENT OF MECHANICAL ENGINEERING UNIVERSITY OF ALBERTA, EDMONTON, ALBERTA, Canada , TG6 2G8
ROCKWELL INTERNATIONAL SCIENCE CENTER, 1049 CAMINO DOS RIOS, THOUSAND OAKS, CA 91360
DEPARTMENT OF MECHANICAL ENGINEERING UNIVERSITY OF VICTORIA, P.O. BOX 1700, VICTORIA, B. C. Canada , V8W 2Y2
Abstract
A causal approach is applied to investigate pulse propagation in random media, which exhibit scattering and viscoelastic losses. Since the approach allows for evaluation of the effective wave number for the entire frequency interval, the transients may be investigated by the classical Fourier method. The scattering mechanism is described by a model introduced by Wu, and the viscoelastic losses by a slightly modified Azimi's law. Extensive numerical results for a transient response of this Wu-Azimi model are presented. It is shown how the pulse reinforcing and delaying effects of multiple scattering are interrelated through a causality constraint.
Copyright © 2009 by Seismological Society of America