Potential and limits of InSAR to characterize interseismic deformation independently of GPS data: Application to the southern San Andreas Fault system
Abstract
The evaluation of long-wavelength deformation associated with interseismic strain accumulation traditionally relies on spatially sparse GPS measurements, or on high spatial-resolution InSAR velocity fields aligned to a GPS-based model. In this approach the InSAR contributes only short-wavelength deformation and the two data sets are dependent, thereby challenging the evaluation of the InSAR uncertainties and the justification of atmospheric corrections. Here we present an analysis using 7 years of Envisat InSAR data to characterize interseismic deformation along the southern San Andreas Fault (SAF) and the San Jacinto Fault (SJF) in southern California, where the SAF bifurcates onto the Mission Creek (MCF) and the Banning (BF) fault strands. We outline the processing steps for using InSAR alone to characterize both the short- and long-wavelength deformation, and evaluate the velocity field uncertainties with independent continuous GPS data. InSAR line-of-sight (LOS) and continuous GPS velocities agree within ∼1–2 mm/yr in the study area, suggesting that multiyear InSAR time series can be used to characterize interseismic deformation with a higher spatial resolution than GPS. We investigate with dislocation models the ability of this mean LOS velocity field to constrain fault slip rates and show that a single viewing geometry can help distinguish between different slip-rate scenarios on the SAF and SJF (∼35 km apart) but multiple viewing geometries are needed to differentiate slip on the MCF and BF (<12 km apart). Our results demonstrate that interseismic models of strain accumulation used for seismic hazards assessment would benefit from the consideration of InSAR mean velocity maps.
Additional Information
© 2016 American Geophysical Union. Received 31 DEC 2015; Accepted 23 FEB 2016; Accepted article online 1 MAR 2016; Published online 31 MAR 2016. We thank the National Aeronautics and Space Administration (NASA) for support through grant NNX12AQ32G and the U.S. Geological Survey National Earthquake Hazards Reduction Program (NEHRP) for support through grants G12AP20096 and G13AP00035. C. W. Johnson is supported by the NSF Graduate Research Fellowship Program through grant DGE1106400. The Envisat original data are copyrighted by the European Space Agency and were provided through the WInSAR archive. We thank three anonymous reviewers and Thorsten Becker for review comments that helped improve the paper. We thank the State University of New York at Buffalo Center for Computational Research for access to their computing resources for processing.Attached Files
Published - Chaussard_et_al-2016-Geochemistry,_Geophysics,_Geosystems.pdf
Supplemental Material - ggge20974-sup-0001-2015GC006246-s01.doc
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Additional details
- Eprint ID
- 67441
- Resolver ID
- CaltechAUTHORS:20160527-103842265
- NNX12AQ32G
- NASA
- G12AP20096
- USGS
- G13AP00035
- USGS
- DGE-1106400
- NSF Graduate Research Fellowship
- Created
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2016-05-27Created from EPrint's datestamp field
- Updated
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2021-11-11Created from EPrint's last_modified field