Maintaining and analyzing California-wide InSAR time-series, derived from the growing archive of ARIA standard products

Simran S. Sangha, Gareth J. Funning, & David Bekaert

Published September 11, 2022, SCEC Contribution #12436, 2022 SCEC Annual Meeting Poster #079

Interferometric Synthetic Aperture Radar (InSAR) is an established technique for mapping displacements of the Earth's surface. The Advanced Rapid Imaging and Analysis (ARIA) Center for Natural Hazards project provides open and free access to an operational archive of standard Sentinel-1 Geocoded UNWrapped interferogram (GUNW) products that can be exploited to produce deformation time series and velocities for the SCEC Community Geodetic Model. We present here an update on our recent work to extend and update our deformation time series for California.

We densified and extended the California archive of standardized interferogram products available through the JPL ARIA project from late 2019 up to the present day. We use this expanded archive to extend our InSAR time series covering southern California beyond the 2019 Ridgecrest earthquake sequence (July 4-5, 2019). To these ends, we use the open source-packages ARIA-tools and MintPy to pre-process interferogram stacks and to compute time-series analyses using the Small Baseline Subset method, respectively. These products and time series are intended as contributions to the SCEC Community Geodetic Model (CGM). To facilitate the production of a combined CGM deformation product, we developed methods to align and reference these time series to GNSS displacement time series spanning California, and to estimate and remove coseismic offsets due to the Ridgecrest earthquakes, to allow the extension of our time series estimates beyond July 2019. Following our previous efforts, we continue to apply tropospheric noise corrections derived from the ECWMF operational weather model through the GACOS service, which improve the uncertainties of the estimated long-term deformation rates. These uncertainties were constrained from our estimated velocities using an open-source bootstrapping approach available through MintPy, which we have also applied to estimate uncertainties in the consensus CGM velocities. We have also started to analyze our velocity data to demonstrate its utility for studying shallow fault creep on the major Holocene faults of California.

Key Words
tectonics, insar, open-access

Citation
Sangha, S. S., Funning, G. J., & Bekaert, D. (2022, 09). Maintaining and analyzing California-wide InSAR time-series, derived from the growing archive of ARIA standard products. Poster Presentation at 2022 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy