Postseismic Reloading: A Source For Temporal Clustering
Of Major Earthquakes Along Individual Fault Segments
S. J. Kenner and M. Simons, California Institute
of Technology
Abstract
Paleoseismic evidence suggests
that earthquake recurrence intervals in some regions can be highly variable,
with clusters of multiple large events separated by much longer periods
of quiescence. Were, we hypothesis that since postseismic processes
have a significant effect on the reloading rate of the coseismic fault,
temporal variations in the amount of stress concentrated in the non-seismogenic
lithosphere can modulate large earthquake recurrence times. We explore
this hypothesis using simple analog spring-dashpot-slider models.
We find that in the presence of small amounts of environmental noise, postseismic
stress transfer on time-scales much longer than an earthquake cycle may
be an important factor in generating clustering behavior. Our results
indicate that low strain-rate environments with a relatively weak non-seismogenic
lithosphere, such as the Basin and Range province in the western United
States, are most susceptible to clustering driven by postseismic stress
recycling mechanisms.
Reference: Kenner, S.J., and M. Simons, Postseismic
Reloading: Postseismic Reloading: A Source For Temporal Clustering Of Major
Earthquakes Along Individual Fault Segments, in prep, Geophyical Journal
International, August 2002.