Earthquake Triggering of Slow-Moving Landslides in Northern California: Insights from 14-day L-band InSAR Time Series Analysis

We quantify slow-moving landslide kinematics across northern California using a 14-day L-band ALOS-2 ScanSAR InSAR time series. After systematically extracting and cleaning the displacement time series, we analyze deformation of 437 landslides across a ∼300 x 400 km area and group time series by relative velocity changes to identify anomalously fast motions. We test associations with external drivers (PGA, precipitation) and landslide attributes (slope, aspect ratio, area). Shaking from the 2022 event shows the strongest association with faster sliding rates. For slides that experienced higher PGA and increased velocities, a piecewise model yields recovery to within ~10% of pre-event rates in ~1.3 years. Using two earthquakes of similar magnitude and location, we demonstrate that rupture dynamics shape the spatial distribution of triggering and supply rare regional constraints on onset and recovery. 

Earthquake Triggering of Slow-Moving Landslides in Northern California: Insights from 14-day L-band InSAR Time Series Analysis, Lindsay (2026), USGS Landslide Hazards Seminar, 20 May 2026.