Widespread initiation, reactivation, and acceleration of landslides in the northern California Coast Ranges due to extreme rainfall

Journal of Geophysical Research: Earth Surface
By: , and 

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Abstract

Episodically to continuously active slow-moving landslides are driven by precipitation. Climate change, which is altering both the frequency and magnitude of precipitation world21 wide, is therefore predicted to have a major impact on landslides. Here we examine the behavior of hundreds of slow-moving landslides in northern California in response to large changes in annual precipitation that occurred between 2016 and 2018. We quantify the landslide displacement using repeat-pass radar interferometry and pixel offset tracking techniques on a novel dataset from the airborne NASA/JPL Uninhabited Aerial Vehicle Synthetic Aperture Radar. We found that 312 landslides were moving due to extreme rainfall during 2017, compared to 119 during 2016, which was the final year of a historic multi-year drought. However, with a return to below average rainfall in 2018, only 146 landslides remained in motion. The increased number of landslides during 2017 was primarily accommodated by landslides that were smaller than the landslides that remained active between 2016 and 2018. Furthermore, by examining a subset of 51 landslides, we found that 49 had increased velocities during 2017 when compared to 2016. Our results show that slow-moving landslides are sensitive to large changes in annual precipitation, particularly the smaller and thinner landslides that likely experience larger basal pore water pressure changes. Based on climate model predictions for the next century in California, which include increases in annual precipitation and increases in the frequency of dry-to-wet extremes, we hypothesize that there will be an overall increase in landslide activity.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Widespread initiation, reactivation, and acceleration of landslides in the northern California Coast Ranges due to extreme rainfall
Series title Journal of Geophysical Research: Earth Surface
DOI 10.1029/2019JF005035
Volume 24
Issue 7
Year Published 2019
Language English
Publisher Wiley
Contributing office(s) Geologic Hazards Science Center
Description 16 p.
First page 1782
Last page 1797
Country United States
State California
Other Geospatial Northern California Coast Range