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Probing the paleoseismic record on the San Andreas Fault System: Patterns and Prognoses


Feb. 7, 2018, noon - 1 p.m.
Geology 1707

Presented By:
Kate Scharer
USGS

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In this talk I will review the types of data collected to document the prehistoric record of large, ground-rupturing earthquakes, and how these data are used to understand fault behavior patterns. Earthquake evidence and radiocarbon dating at individual sites along the southern San Andreas Fault suggest that earthquake recurrence is not clustered; rather it is more regular than would be expected from a random distribution. Comparing records along the fault system, simple models of the maximum rupture length, and thus estimates of moment release, show interesting patterns that differ from current probabilistic hazard models and suggest the most recent event in 1857 was larger than average. Finally, an evaluation of the most robust, long records from around the plate boundary system reveals that fine-scale variations that appear in the historic record are not demonstrated in the paleoseismic record.