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Quasi-periodic recurrence of large earthquakes on the southern San Andreas fault

Geology

By:
, , , and
DOI: 10.1130/G30746.1

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Abstract

It has been 153 yr since the last large earthquake on the southern San Andreas fault (California, United States), but the average interseismic interval is only ~100 yr. If the recurrence of large earthquakes is periodic, rather than random or clustered, the length of this period is notable and would generally increase the risk estimated in probabilistic seismic hazard analyses. Unfortunately, robust characterization of a distribution describing earthquake recurrence on a single fault is limited by the brevity of most earthquake records. Here we use statistical tests on a 3000 yr combined record of 29 ground-rupturing earthquakes from Wrightwood, California. We show that earthquake recurrence there is more regular than expected from a Poisson distribution and is not clustered, leading us to conclude that recurrence is quasi-periodic. The observation of unimodal time dependence is persistent across an observationally based sensitivity analysis that critically examines alternative interpretations of the geologic record. The results support formal forecast efforts that use renewal models to estimate probabilities of future earthquakes on the southern San Andreas fault. Only four intervals (15%) from the record are longer than the present open interval, highlighting the current hazard posed by this fault.

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Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Quasi-periodic recurrence of large earthquakes on the southern San Andreas fault
Series title:
Geology
DOI:
10.1130/G30746.1
Volume
38
Issue:
6
Year Published:
2010
Language:
English
Publisher:
Geological Society of America
Publisher location:
Boulder, CO
Contributing office(s):
Earthquake Science Center
Description:
4 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geology
First page:
555
Last page:
558
Country:
United States
State:
California
Other Geospatial:
San Andreas Fault