Holocene geologic slip rate for the Banning strand of the southern San Andreas Fault, southern California
File(s)
Author(s)
Type
Journal Article
Abstract
Northwest directed slip from the southern San Andreas Fault is transferred to the Mission Creek, Banning, and Garnet Hill fault strands in the northwestern Coachella Valley. How slip is partitioned between these three faults is critical to southern California seismic hazard estimates but is poorly understood. In this paper, we report the first slip rate measured for the Banning fault strand. We constrain the depositional age of an alluvial fan offset 25 ± 5 m from its source by the Banning strand to between 5.1 ± 0.4 ka (95% confidence interval (CI)) and 6.4 + 3.7/−2.1 ka (95% CI) using U-series dating of pedogenic carbonate clast coatings and 10Be cosmogenic nuclide exposure dating of surface clasts. We calculate a Holocene geologic slip rate for the Banning strand of 3.9 + 2.3/−1.6 mm/yr (median, 95% CI) to 4.9 + 1.0/−0.9 mm/yr (median, 95% CI). This rate represents only 25–35% of the total slip accommodated by this section of the southern San Andreas Fault, suggesting a model in which slip is less concentrated on the Banning strand than previously thought. In rejecting the possibility that the Banning strand is the dominant structure, our results highlight an even greater need for slip rate and paleoseismic measurements along faults in the northwestern Coachella Valley in order to test the validity of current earthquake hazard models. In addition, our comparison of ages measured with U-series and 10Be exposure dating demonstrates the importance of using multiple geochronometers when estimating the depositional age of alluvial landforms.
Date Issued
2015-08-01
Date Acceptance
2015-07-11
Citation
Journal of Geophysical Research. Solid Earth, 2015, 120 (8), pp.5639-5663
ISSN
2169-9313
Publisher
American Geophysical Union (AGU)
Start Page
5639
End Page
5663
Journal / Book Title
Journal of Geophysical Research. Solid Earth
Volume
120
Issue
8
Copyright Statement
© 2015. American Geophysical Union.All Rights Reserved.
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000362224100014&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Science & Technology
Physical Sciences
Geochemistry & Geophysics
Banning fault strand
southern San Andreas Fault
slip rate
Be-10 exposure dating
U series pedogenic carbonate
earthquake hazard
EARTHQUAKE RUPTURE FORECAST
SITU COSMOGENIC NUCLIDES
NORTH PALM-SPRINGS
HALF-LIFE
TECTONIC GEOMORPHOLOGY
PEDOGENIC CARBONATE
FLUVIAL TERRACES
SURFACE RUPTURES
COACHELLA VALLEY
SALTON TROUGH
Publication Status
Published