Bulletin of the Seismological Society of America; December 2004; v. 94; no. 6;
p. 2079-2089
© 2004 Seismological Society of America
Earthquake Simulation by Restricted Random Walks
Steven N. Ward1
1 Institute of Geophysics and Planetary
Physics
University of California–Santa Cruz
Santa Cruz, CA
95064
This article simulates earthquake slip distributions as restricted random
walks. Random walks offer several unifying insights into earthquake behaviors
that physically based simulations do not. With properly tailored variables,
random walks generate observed power law rates of earthquake number versus
earthquake magnitude (the Gutenberg–Richter relation). Curiously,
b-value, the slope of this distribution, not only fixes the ratio of
small to large events but also dictates diverse earthquake scaling laws such as
mean slip versus fault length and moment versus mean slip. Moreover,
b-value determines the overall shape and roughness of earthquake
ruptures. For example, mean random walk quakes with b =
–
have elliptical slip distributions characteristic of a uniform
stress drop on a crack. Random walk earthquake simulators, tuned by comparison
with field data, provide improved bases for statistical inference of earthquake
behavior and hazard.
Copyright © 2004 by the Seismological Society of America.