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Insights From a New Global Coseismic Landslide Runout Length Dataset

Description: 

The hazard and possible impacts posed by earthquake-triggered (coseismic) landslides is a combination of triggering and the runout length (size) of each landslide. While landslide triggering models have benefitted from the continued development and sharing of landslide inventories after earthquakes, runout lengths are rarely mapped, forcing modelers to rely on simplified relationships from aseismic slides or computationally expensive runout simulations. We present an automated method for measuring the runout length developed and validated on 1579 coseismic landslides compiled from published inventories. Combining several readily computed geometric and topographic attributes, the proposed automated runout model closely matches manually mapped runout lengths for slides ranging from several meters to kilometers in length. We then apply this model to the USGS global coseismic landslide inventory repository to develop a database of over 80,000 landslides with runout length estimates. We find global coseismic landslide runout lengths do not follow established fall-angle or mobility relationships developed for aseismic landslides, suggesting the need for new models to better predict the extent, impacts, and therefore risk, associated with coseismic landslides. We will present the results of our runout model, as well as an analysis of the factors driving the non-linear behavior of coseismic landslide mobility as a function of landslide size and topography. These data and results provide the building blocks for new coseismic landslide runout models to improve hazard and risk forecast models as well as enabling new near-real-time estimates of the impacts of landslides triggered by earthquakes.

Session: Coseismic Ground Failure: Advances in Modeling, Impacts and Communication

Type: Oral

Date: 4/20/2023

Presentation Time: 08:15 AM (local time)

Presenting Author: Alex Grant

Student Presenter: No

Invited Presentation: 

Authors