How Do Creeping Landslides Respond to Earthquake Shaking?
Description:
Ground shaking in the near field of large earthquakes can instantly turn stable steep hillslopes into catastrophic slope failures. This type of immediate response of earthquake-triggered, first-time landslides has been widely observed and recorded around the globe. However, less well known is how slow-moving landslides respond to seismic shaking. Long-term creeping landslides are dominantly located on gentle hillslopes and their kinematics are often tied to slope hydrology; however, few have been documented to accelerate into catastrophic failure by earthquake shaking. Does this indicate earthquake shaking barely affects the stability of large creeping landslides?
Here, we use the M6.4 Ferndale, California earthquake on 12 Dec 2022 near the Mendocino Triple Junction as a typical example to answer this question. By utilizing ground deformation maps generated from the ALOS-2 Stripmap and ScanSAR satellite radar images between 2016 and 2022, we find that the Ferndale earthquake reactivated or accelerated seven large creeping landslides within 35 km of the epicenter, though none of them failed catastrophically. Five other known landslides within the same range did not show apparent acceleration immediately after the earthquake, possibly owing to their topographical setting or their delayed response to seismic shaking caused by shear-zone material compaction/dilation and pore-pressure redistribution. Potentially, earthquakes also increase surface cracking and create void space in the landslide body, thereby promoting post-earthquake rainwater infiltration and landslide movement. To validate these hypotheses, we are conducting studies using more incoming ALOS-2 ScanSAR data with 14-day revisit, which are scheduled for acquisition throughout 2023. The tectonically active U.S. West Coast hosts hundreds of large creeping landslides, and it is essential to better understand how earthquakes may impact the future of these unstable hillslopes.
Session: Coseismic Ground Failure: Advances in Modeling, Impacts and Communication
Type: Oral
Date: 4/20/2023
Presentation Time: 10:45 AM (local time)
Presenting Author: Yuankun Xu
Student Presenter: No
Invited Presentation:
Authors
Yuankun Xu Presenting Author Corresponding Author yuankunx@berkeley.edu University of California, Berkeley |
Danielle Lindsay danielle.lindsay@berkeley.edu University of California, Berkeley |
Roland Burgmann burgmann@berkeley.edu University of California, Berkeley |
Eric Fielding eric.j.fielding@jpl.nasa.gov NASA Jet Propulsion Laboratory |
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How Do Creeping Landslides Respond to Earthquake Shaking?
Category
Coseismic Ground Failure: Advances in Modeling, Impacts and Communication