Irregular Recurrence of Large Earthquakes Along the San Andreas Fault: Evidence from Trees

TitleIrregular Recurrence of Large Earthquakes Along the San Andreas Fault: Evidence from Trees
Publication TypeJournal Article
Year of Publication1988
AuthorsJacoby GC, Sheppard PR
JournalScience
Volume241
Pagination196-199
Date Published07/1988
Abstract

Old trees growing along the San Andreas fault near Wrightwood, California, record in their annual ring-width patterns the effects of a major earthquake in the fall or winter of 1812 to 1813. Paleoseismic data and historical information indicate that this event was the "San Juan Capistrano" earthquake of 8 December 1812, with a magnitude of 7.5. The discovery that at least 12 kilometers of the Mojave segment of the San Andreas fault ruptured in 1812, only 44 years before the great January 1857 rupture, demonstrates that intervals between large earthquakes on this part of the fault are highly variable. This variability increases the uncertainty of forecasting destructive earthquakes on the basis of past behavior and accentuates the need for a more fundamental knowledge of San Andreas fault dynamics.