SCEC Award Number 10108 View PDF
Proposal Category Individual Proposal (Data Gathering and Products)
Proposal Title Slip rate for the North Branch of the San Andreas fault, San Bernardino Valley
Investigator(s)
Name Organization
Ray Weldon University of Oregon
Other Participants one graduate student
SCEC Priorities A2, A1, A7 SCEC Groups Geology, Geodesy, SHRA
Report Due Date 02/28/2011 Date Report Submitted N/A
Project Abstract
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Intellectual Merit This study provides a preliminary slip rate of ~2 mm/yr across the North Branch of the San Andreas fault near San Bernardino. The only cited slip rates for the NBSAF are from Weldon (1993; an unpublished report to the Army Corps) at Santa Ana River and Sieh et al. (1994; a GSA abstract) at City Creek, and the structure has largely been ignored in either seismic hazard analysis or its contribution to the strain across the San Andreas fault in the San Bernardino Valley to San Gorgonio Pass region. If the slip rate is ~2 mm/yr, as our preliminary results suggest, it may be a significant independent source of earthquakes and it adds to the discrepancy between the geologically determined slip rate across the SAF (~11 mm/yr without the NBSAF; McGill et al., 2008) and the geodetically determined rate (~5 mm/yr).
Broader Impacts This project involved a graduate student, who has gained field experience and will learn to analyze cosmogenic isotope samples later this year. The project strengthens our understanding of seismic hazard in the region and the age of Quaternary deposits.
Exemplary Figure N/A