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Southern San Andreas-San Jacinto fault system slip rates estimated from earthquake cycle models constrained by GPS and interferometric synthetic aperture radar observations

Lundgren, Paul and Hetland, Eric A. and Liu, Zhen and Fielding, Eric J. (2009) Southern San Andreas-San Jacinto fault system slip rates estimated from earthquake cycle models constrained by GPS and interferometric synthetic aperture radar observations. Journal of Geophysical Research B, 114 . Art. No. B02403. ISSN 0148-0227. http://resolver.caltech.edu/CaltechAUTHORS:20090911-084158431

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Abstract

We use ground geodetic and interferometric synthetic aperture radar satellite observations across the southern San Andreas (SAF)-San Jacinto (SJF) fault systems to constrain their slip rates and the viscosity structure of the lower crust and upper mantle on the basis of periodic earthquake cycle, Maxwell viscoelastic, finite element models. Key questions for this system are the SAF and SJF slip rates, the slip partitioning between the two main branches of the SJF, and the dip of the SAF. The best-fitting models generally have a high-viscosity lower crust (η = 10^(21) Pa s) overlying a lower-viscosity upper mantle (η = 10^(19) Pa s). We find considerable trade-offs between the relative time into the current earthquake cycle of the San Jacinto fault and the upper mantle viscosity. With reasonable assumptions for the relative time in the earthquake cycle, the partition of slip is fairly robust at around 24–26 mm/a for the San Jacinto fault system and 16–18 mm/a for the San Andreas fault. Models for two subprofiles across the SAF-SJF systems suggest that slip may transfer from the western (Coyote Creek) branch to the eastern (Clark-Superstition hills) branch of the SJF from NW to SE. Across the entire system our best-fitting model gives slip rates of 2 ± 3, 12 ± 9, 12 ± 9, and 17 ± 3 mm/a for the Elsinore, Coyote Creek, Clark, and San Andreas faults, respectively, where the large uncertainties in the slip rates for the SJF branches reflect the large uncertainty in the slip rate partitioning within the SJF system.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/2008JB005996DOIArticle
ORCID:
AuthorORCID
Liu, Zhen0000-0002-6313-823X
Fielding, Eric J.0000-0002-6648-8067
Additional Information:© 2009 American Geophysical Union. Received 7 August 2008; revised 1 December 2008; accepted 15 December 2008; published 21 February 2009. We thank the European Space Agency for ERS data provided through theWInSAR archive. CMM3data were provided through the Southern California Earthquake Center.Maps and profiles in this paper were generated using the public domain Generic Mapping Tools (GMT) software [Wessel and Smith, 1995]. We greatly appreciate thorough and insightful reviews by Noah Fay, one anonymous reviewer, and associate editor Tim Dixon. E.A.H. thanks the Tectonics Observatory and the Seismological Laboratory, Caltech, for postdoctoral support. This research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration and funded through the internal Research and Technology Development program.
Group:Caltech Tectonics Observatory, Seismological Laboratory
Funders:
Funding AgencyGrant Number
NASA/JPL/CaltechUNSPECIFIED
JPL Research and Technology Development FundUNSPECIFIED
Subject Keywords:San Andreas fault; San Jacinto fault; InSAR
Other Numbering System:
Other Numbering System NameOther Numbering System ID
Caltech Tectonics Observatory114
Record Number:CaltechAUTHORS:20090911-084158431
Persistent URL:http://resolver.caltech.edu/CaltechAUTHORS:20090911-084158431
Official Citation:Lundgren, P., E. A. Hetland, Z. Liu, and E. J. Fielding (2009), Southern San Andreas-San Jacinto fault system slip rates estimated from earthquake cycle models constrained by GPS and interferometric synthetic aperture radar observations, J. Geophys. Res., 114, B02403, doi:10.1029/2008JB005996.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15753
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:15 Sep 2009 16:25
Last Modified:20 Oct 2017 23:35

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