8 years of ALOS-2 observations across Central and Northern California: Distributed plate-boundary deformation, creeping faults, slow-moving landslides.

Danielle Lindsay, & Roland Bürgmann

Submitted September 10, 2023, SCEC Contribution #13234, 2023 SCEC Annual Meeting Poster #061

We present eight years of ALOS-2 observations across Northern California illustrating processes related to the large-scale tectonically driven deformation associated with the passage of the Mendocino Triple Junction and small-scale fault creep and slow-moving landslides. Interferometry with ALOS-2 ScanSAR data can accurately measure deformation across these spatial scales providing a spatially continuous dataset that extends observations into typically hard-to-reach places. The L-band Synthetic Aperture Radar (SAR) signal maintains coherence across challenging terrain, providing the ability to continuously map deformation in highly vegetated, snow-covered, and steep regions. We present time series from ALOS-2 ScanSAR data for 2015 -- 2023, imaging the area from Monterey Bay to the California-Oregon border across the width of the state. Importantly, observations have been made fortnightly since July 2021 along descending track 170, allowing for detailed time series analysis and providing insight into potential applications of the upcoming NiSAR mission. These data are available through a data sharing agreement between NASA and JAXA, with original ALOS-2/PALSAR-2 Data Products provided by JAXA.

We highlight observations of distributed plate-boundary deformation, creeping faults, slow-moving landslides, and geothermal subsidence. In detail, we analyze surface fault creep for the Maacama and ​​Bartlett Springs fault zones. We compare our slow-moving landslides with previously published inventories and investigate earthquake-triggered accelerations following the 2022 Ferndale Earthquake. In the Bay Area, we compare the ALOS-2 results with the Sentinel-1 velocity field of Li et al. (2023). By accurately mapping deformation at tens-of-meters to hundreds-of-kilometers scales, we can better understand where and how faults accumulate strain, estimate where a landslide might catastrophically fail, and understand the effects of anthropogenic activities on the landscape.

Citation
Lindsay, D., & Bürgmann, R. (2023, 09). 8 years of ALOS-2 observations across Central and Northern California: Distributed plate-boundary deformation, creeping faults, slow-moving landslides.. Poster Presentation at 2023 SCEC Annual Meeting.

Related Projects & Working Groups
Tectonic Geodesy