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Locally and remotely triggered aseismic slip on the central San Jacinto Fault near Anza, CA, from joint inversion of seismicity and strainmeter data

Inbal, A. and Ampuero, J.-P. and Avouac, J.-P. (2017) Locally and remotely triggered aseismic slip on the central San Jacinto Fault near Anza, CA, from joint inversion of seismicity and strainmeter data. Journal of Geophysical Research. Solid Earth, 122 (4). pp. 3033-3061. ISSN 2169-9313. http://resolver.caltech.edu/CaltechAUTHORS:20170418-081344017

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Abstract

We study deep aseismic slip along the central section of the San Jacinto Fault, near the Anza Seismic Gap, in southern California. Elevated strain rates following the remote M_w7.2, 4 April 2010 El Mayor-Cucapah and the local M_w5.4, 7 July 2010 Collins Valley earthquakes were recorded by Plate Boundary Observatory borehole strainmeters near Anza and were accompanied by vigorous aftershock sequences. We introduce a method to infer the distribution of triggered aseismic slip from combined seismicity and geodetic data, based on a rate-and-state friction model that maps observed changes in seismicity rates into stress changes. We invert for the cumulative slip in the 10 day period following each main shock. Synthetic tests show that the effect of aftershock interactions on the inferred slip distribution is negligible. The joint data set is more consistent with a model in which aseismic slip on a principal fault triggers seismicity on adjacent faults than with one in which aseismic slip and seismicity are coplanar. Our results indicate that aseismic slip primarily occurs along the rim of two seismicity clusters adjacent to Anza Gap, as well as beneath the Anza Gap itself, at depths larger than 10 km. The triggered aseismic slip generated by the two main shocks has little overlap, a pattern also found in sequences of large earthquakes occurring on a same fault. Stresses inferred from seismic activity leading to the Collins Valley main shock suggest that this earthquake was triggered by stresses imposed by the El Mayor-Cucapah remote-triggered aseismic slip, which persisted for more than 2 months.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1002/2016JB013499DOIArticle
http://onlinelibrary.wiley.com/doi/10.1002/2016JB013499/abstractPublisherArticle
ORCID:
AuthorORCID
Inbal, A.0000-0001-8848-7279
Ampuero, J.-P.0000-0002-4827-7987
Avouac, J.-P.0000-0002-3060-8442
Additional Information:© 2017 American Geophysical Union. Received 26 AUG 2016; Accepted 6 APR 2017; Accepted article online 17 APR 2017; Published online 27 APR 2017. We thank the Editor, Y. Ben-Zion, and two anonymous reviewers for their thoughtful reviews. Discussions with A. Ziv have contributed to the development of the joint inversion technique. Comments from R. Bürgmann and C. Johnsson have improved the quality of this manuscript. A. Inbal work at the University of California, Berkeley, was supported by a postdoctoral fellowship for seismological research from the Israeli Minister of Energy and Water. Waveform data used in this study were recorded and maintained by the ANZA Seismic Network (doi:10.7914/SN/AZ), the Southern California Seismic Network (doi:10.7914/SN/CI), and the Plate Boundary Observatory Borehole Seismic Network (no doi available at present).
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
Ministry of Energy and Water (Israel)UNSPECIFIED
Subject Keywords:Seismogeodesy; Mechanics of Faulting; Earthquake Triggering; Transient Deformation
Record Number:CaltechAUTHORS:20170418-081344017
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20170418-081344017
Official Citation:Inbal, A., J.-P. Ampuero, and J.-P. Avouac (2017), Locally and remotely triggered aseismic slip on the central San Jacinto Fault near Anza, CA, from joint inversion of seismicity and strainmeter data, J. Geophys. Res. Solid Earth, 122, 3033–3061, doi:10.1002/2016JB013499
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:76627
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:25 Apr 2017 19:32
Last Modified:02 Oct 2017 17:58

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