Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California

We analyze a suite of geodetic observations across the Imperial Fault in southern California that span all parts of the earthquake cycle. Coseismic and postseismic surface slips due to the 1979 M 6.6 Imperial Valley earthquake were recorded with trilateration and alignment surveys by Harsh (1982) an...

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Main Authors: Lindsey, Eric O., Fialko, Yuri
Other Authors: Earth Observatory of Singapore
Format: Article
Language:English
Published: 2016
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Online Access:https://hdl.handle.net/10356/83990
http://hdl.handle.net/10220/41541
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Institution: Nanyang Technological University
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spelling sg-ntu-dr.10356-839902020-09-26T21:34:01Z Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California Lindsey, Eric O. Fialko, Yuri Earth Observatory of Singapore Imperial Fault creep We analyze a suite of geodetic observations across the Imperial Fault in southern California that span all parts of the earthquake cycle. Coseismic and postseismic surface slips due to the 1979 M 6.6 Imperial Valley earthquake were recorded with trilateration and alignment surveys by Harsh (1982) and Crook et al. (1982), and interseismic deformation is measured using a combination of multiple interferometric synthetic aperture radar (InSAR)-viewing geometries and continuous and survey-mode GPS. In particular, we combine more than 100 survey-mode GPS velocities with InSAR data from Envisat descending tracks 84 and 356 and ascending tracks 77 and 306 (149 total acquisitions), processed using a persistent scatterers method. The result is a dense map of interseismic velocities across the Imperial Fault and surrounding areas that allows us to evaluate the rate of interseismic loading and along-strike variations in surface creep. We compare available geodetic data to models of the earthquake cycle with rate- and state-dependent friction and find that a complete record of the earthquake cycle is required to constrain key fault properties including the rate-dependence parameter (a − b) as a function of depth, the extent of shallow creep, and the recurrence interval of large events. We find that the data are inconsistent with a high (>30 mm/yr) slip rate on the Imperial Fault and investigate the possibility that an extension of the San Jacinto-Superstition Hills Fault system through the town of El Centro may accommodate a significant portion of the slip previously attributed to the Imperial Fault. Models including this additional fault are in better agreement with the available observations, suggesting that the long-term slip rate of the Imperial Fault is lower than previously suggested and that there may be a significant unmapped hazard in the western Imperial Valley. Published version 2016-10-04T06:06:23Z 2019-12-06T15:35:59Z 2016-10-04T06:06:23Z 2019-12-06T15:35:59Z 2016 Journal Article Lindsey, E. O., & Fialko, Y. (2016). Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California. Journal of Geophysical Research: Solid Earth, 121(2), 1097-1113. 2169-9313 https://hdl.handle.net/10356/83990 http://hdl.handle.net/10220/41541 10.1002/2015JB012516 en Journal of Geophysical Research: Solid Earth © 2016 American Geophysical Union (AGU). This paper was published in Journal of Geophysical Research: Solid Earth and is made available as an electronic reprint (preprint) with permission of American Geophysical Union (AGU). The published version is available at: [http://dx.doi.org/10.1002/2015JB012516]. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper is prohibited and is subject to penalties under law. 17 p. application/pdf
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Imperial Fault
creep
spellingShingle Imperial Fault
creep
Lindsey, Eric O.
Fialko, Yuri
Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
description We analyze a suite of geodetic observations across the Imperial Fault in southern California that span all parts of the earthquake cycle. Coseismic and postseismic surface slips due to the 1979 M 6.6 Imperial Valley earthquake were recorded with trilateration and alignment surveys by Harsh (1982) and Crook et al. (1982), and interseismic deformation is measured using a combination of multiple interferometric synthetic aperture radar (InSAR)-viewing geometries and continuous and survey-mode GPS. In particular, we combine more than 100 survey-mode GPS velocities with InSAR data from Envisat descending tracks 84 and 356 and ascending tracks 77 and 306 (149 total acquisitions), processed using a persistent scatterers method. The result is a dense map of interseismic velocities across the Imperial Fault and surrounding areas that allows us to evaluate the rate of interseismic loading and along-strike variations in surface creep. We compare available geodetic data to models of the earthquake cycle with rate- and state-dependent friction and find that a complete record of the earthquake cycle is required to constrain key fault properties including the rate-dependence parameter (a − b) as a function of depth, the extent of shallow creep, and the recurrence interval of large events. We find that the data are inconsistent with a high (>30 mm/yr) slip rate on the Imperial Fault and investigate the possibility that an extension of the San Jacinto-Superstition Hills Fault system through the town of El Centro may accommodate a significant portion of the slip previously attributed to the Imperial Fault. Models including this additional fault are in better agreement with the available observations, suggesting that the long-term slip rate of the Imperial Fault is lower than previously suggested and that there may be a significant unmapped hazard in the western Imperial Valley.
author2 Earth Observatory of Singapore
author_facet Earth Observatory of Singapore
Lindsey, Eric O.
Fialko, Yuri
format Article
author Lindsey, Eric O.
Fialko, Yuri
author_sort Lindsey, Eric O.
title Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
title_short Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
title_full Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
title_fullStr Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
title_full_unstemmed Geodetic constraints on frictional properties and earthquake hazard in the Imperial Valley, Southern California
title_sort geodetic constraints on frictional properties and earthquake hazard in the imperial valley, southern california
publishDate 2016
url https://hdl.handle.net/10356/83990
http://hdl.handle.net/10220/41541
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