Map of the study site in the northern California Coast Ranges.
Map of the northern California Coast Ranges study site. Black polygons outline the active landslides analyzed in this study. Elevation (in meters) is shown by green to white color gradient. Black boxes show the left looking UAVSAR swaths and corresponding track numbers with airplanes showing flight direction. Red arrow shows the location of a U.S. Geological Survey (USGS) landslide field site. Blue lines show major rivers and some tributaries in landslide areas. Inset shows a map of California with a star corresponding to the study site. Credit: Handwerger et al. [2021], Figure 1
Source: Journal of Geophysical Research: Earth Surface

The largest and fastest slow-moving landslides can cause substantial hazard to infrastructure and communities. Nevertheless, assessing the thickness, mechanical state, and displacement rate of such landslides is very difficult.

Handwerger et al. [2021] use radar measurements obtained from an Uninhabited Aerial Vehicle to measure the 3D velocity over more than a hundred landslides in Northern California. Further, they used the displacement pattern to infer the landslide thickness and strength.

They found that these slow landslides had geometries similar to rapidly failing landslides, and also that beyond a certain size, large landslides seemed to grow only in area and not grow thicker. Last, and more puzzling, they found that larger landslides are weaker. To explain this, the authors propose that larger landslides have more chance to incorporate the very weak portion of the heterogeneous local lithology.

Citation: Handwerger, A. L., Booth, A. M., Huang, M.‐H., & Fielding, E. J. [2021]. Inferring the subsurface geometry and strength of slow‐moving landslides using 3‐D velocity measurements from the NASA/JPL UAVSAR. Journal of Geophysical Research: Earth Surface, 126, e2020JF005898.

—Odin Marc, Associate Editor, JGR: Earth Surface

Text © 2021. The authors. CC BY-NC-ND 3.0
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