A New Geological Slip Rate Estimate for the Calico Fault, Eastern California: Implications for Geodetic Versus Geologic Rate Estimates in the Eastern California Shear Zone

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Poster Session

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Fault slip rate is fundamental to accurate seismic hazard assessment. In the Mojave Desert section of the Eastern California Shear Zone previous studies have suggested a discrepancy between short-term geodetic and long-term geologic slip rate estimates. Understanding the origin of this discrepancy could lead to better understanding of stress evolution, and improve earthquake hazard estimates in general. We measured offsets in alluvial fans along the Calico fault near Newberry Springs, California, and used exposure age dating based on the cosmogenic nuclide 10Be to date the offset landforms. We derive a mean slip rate of 3.6 mm/yr, representing an average over the last few hundred thousand years, significantly faster than previous estimates.

Considering numerous faults in the Mojave Desert and limited geologic slip rate estimates, it is premature to claim a geologic versus geodetic “discrepancy” for the ECSZ. More slip rate data, from all faults with the ECSZ, are needed to provide a statistically meaningful assessment of the geologic rates for each of the faults comprising the ECSZ.


An article of the same title is in press with International Geology Review; additional authors for the article are P. Figueiredob & R. Malservisi.

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Citation / Publisher Attribution

Presented at the AGU Fall Meeting on December 15, 2017 in New Orleans, LA