Southern surface rupture associated with the M 7.3 1992 Landers, California, earthquake

Bulletin of the Seismological Society of America
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Abstract

Although most evidence suggests that the 28 June 1992 M 7.3 Landers earthquake ruptured unilaterally north, significant surface rupture was mapped on the Eureka Peak and Burnt Mountain faults, to the south of the Landers epicenter. An eyewitness account reports that surface rupture occurred on the northern Eureka Peak fault within approximately 35 sec of the mainshock initiation. Array analysis of the Landers mainshock provides evidence in support of this report; a significant southern subevent in the early mainshock coda. I also analyze dense array recordings of a M 5.6 aftershock that occurred 3 min after the mainshock at 34°7.65′N, 116°23.82′W and show that there is strong evidence that this event was also associated with significant rupture on the Eureka Peak fault. This analysis thus suggests that the Eureka Peak fault rupture was not caused by direct bilateral mainshock rupture but instead was initially triggered less than a minute after the mainshock and reruptured by the M 5.6 aftershock. Results for the evolution of the Landers sequence suggest that mainshock subevents may in some cases be accurately described as aftershocks (i.e., disjoint triggered events) that occur within the duration of mainshock strong ground motion.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Southern surface rupture associated with the M 7.3 1992 Landers, California, earthquake
Series title Bulletin of the Seismological Society of America
Volume 84
Issue 3
Year Published 1994
Language English
Publisher Seismological Society of America
Description 9 p.
First page 817
Last page 825