Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults

Bulletin of the Seismological Society of America
By:  and 

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Abstract

Long Valley caldera lies within a left-stepping offset in the north-northwest-striking Sierra Nevada range-front normal faults with the Hilton Creek fault to the south and Hartley Springs fault to the north. Both Uniform California Earthquake Rupture Forecast (UCERF) 2 and its update, UCERF3, depict slip on these major range-front normal faults as extending well into the caldera, with significant normal slip on overlapping, subparallel segments separated by ∼10  km. This depiction is countered by (1) geologic evidence that normal faulting within the caldera consists of a series of graben structures associated with postcaldera magmatism (intrusion and tumescence) and not systematic down-to-the-east displacements consistent with distributed range-front faulting and (2) the lack of kinematic evidence for an evolving, postcaldera relay ramp structure between overlapping strands of the two range-front normal faults. The modifications to the UCERF depiction described here reduce the predicted shaking intensity within the caldera, and they are in accord with the tectonic influence that underlapped offset range-front faults have on seismicity patterns within the caldera associated with ongoing volcanic unrest.

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Long Valley caldera and the UCERF depiction of Sierra Nevada range-front faults
Series title Bulletin of the Seismological Society of America
DOI 10.1785/0120150149
Volume 105
Issue 6
Year Published 2015
Language English
Publisher Seismological Society of America
Contributing office(s) Volcano Science Center
Description 7 p.
First page 3189
Last page 3195
Online Only (Y/N) N
Additional Online Files (Y/N) N