Exciting news! We're transitioning to the Statewide California Earthquake Center. Our new website is under construction, but we'll continue using this website for SCEC business in the meantime. We're also archiving the Southern Center site to preserve its rich history. A new and improved platform is coming soon!

Imaging tectonic and anthropogenic processes using ALOS-2 and Sentinel-1 InSAR

Zhen Liu, Paul Lundgren, & Cunren Liang

Published August 16, 2019, SCEC Contribution #9905, 2019 SCEC Annual Meeting Poster #210

The improved spatiotemporal resolution of surface deformation from recent satellite sensors such as Sentinel-1 (S-1) and ALOS-2 provides a great opportunity to better constrain and understand both tectonic and non-tectonic processes. In this study, we combine satellite InSAR and in-situ GPS to image fault and anthropogenic deformation. We present InSAR time series results in central and southern California region from selected tracks using S-1 and ALOS-2 ScanSAR data. We estimate azimuth mis-registration between single look complex (SLC) images of S-1 in a stack sense to achieve accurate azimuth co-registration between SLC images for low coherence and/or long interval interferometric pairs. The pervasive existence of ionosphere artifacts in ALOS-2 ScanSAR interferometry makes it crucial to properly correct them for accurate deformation measurements. We show a split-spectrum based ionosphere correction is able to remove ionospheric features successfully while still retaining long-wavelength deformation signals. Our results in central California reveal the large-scale ground subsidence in the San Joaquin Valley due to over-exploitation of groundwater along with localized near-fault creep across the central San Andreas Fault. Groundwater related deformation is spatially and temporally variable and is composed of both recoverable elastic and non-recoverable inelastic components. InSAR time series are compared to GPS and well-water hydraulic head in-situ time series to understand water storage processes and mass loading changes. Our ALOS-2 ScanSAR velocities across the southern San Andreas fault system show that they agree well with GPS velocities, with an RMS error ~4-5mm/yr. The consistency between ALOS-2 and GPS over large areas suggests that ALOS-2 ScanSAR data have great potential in mapping long-wavelength deformation signals accurately without reliance on using GPS as ground control points.

Citation
Liu, Z., Lundgren, P., & Liang, C. (2019, 08). Imaging tectonic and anthropogenic processes using ALOS-2 and Sentinel-1 InSAR. Poster Presentation at 2019 SCEC Annual Meeting.


Related Projects & Working Groups
Tectonic Geodesy