WITHDRAWN Impacts of Anthropogenic Modification on Coseismic Landslide Triggering
Description:
WITHDRAWN Anthropogenic landscape modification (e.g., reshaping topography, altering land use, placing fill) has long been recognized as a factor affecting slope stability. However, quantifying the impact of anthropogenic modification on slope stability is challenging and regional-scale landslide assessments often only indirectly consider (or omit) anthropogenic impacts. Here we investigate the impacts of anthropogenic modification on coseismic landslides by reexamining landslides triggered during the 2011 M9.1 Tohoku, Japan earthquake and calculating differences in apparent strength at failure between natural and modified hillslopes.
We first present a revised landslide inventory of the Tohoku earthquake, classifying landslide failure mode, the presence of anthropogenic modification, and impacts to the built environment for each landslide. With this enhanced inventory, we find nearly all (99.7%) landslides that impacted the built environment originated in anthropogenically modified hillslopes. We then quantify the change in apparent hillslope strength between natural and modified landslide sources using 1452 shallow disrupted soil slides triggered during the Tohoku earthquake to better understand how earthquake triggered landslide hazard is affected by anthropogenic modification. Changes in apparent strength due to anthropic modification of hillslopes are found to vary from increases of 9% to 12% losses in apparent strength, which are correlated to geologic age and intact material strength. Older, stronger, bedrock materials were found to systematically become weaker, and therefore more landslide prone, when modified, while young and relatively weak Holocene deposits are stronger following modification. Incorporating anthropogenic changes to the landscape may be an important component of future landslide hazard and risk modeling as they inherently have a disproportionate impact to the built environment and human exposure.
Session: Earthquake-triggered Ground Failure: Data, Hazards, Impacts and Models [Poster]
Type: Poster
Date: 4/17/2025
Presentation Time: 08:00 AM (local time)
Presenting Author: Alex
Student Presenter: No
Invited Presentation:
Poster Number: 3
Authors
Alex Grant Presenting Author Corresponding Author agrant@usgs.gov U.S. Geological Survey |
Joseph Wartman wartman@uw.edu University of Washington |
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WITHDRAWN Impacts of Anthropogenic Modification on Coseismic Landslide Triggering
Session
Earthquake-triggered Ground Failure: Data, Hazards, Impacts and Models