Geospatial characterization of causative factors for recent landslides in the Oregon Coast Range

摘要

The Oregon coast range is highly prone to landslides, which create a significant maintenance problem for the Department of Transportation. Many causative factors contribute to the failure of these slopes including slope angle, slope and terrain roughness, weak soils, significant precipitation, and high groundwater levels. These unstable slopes are further threatened by impending seismic hazards, such as the Cascadia Subduction Zone. These coast range landslides are capable of isolating communities by blocking the limited number of lifeline highway corridors, critical for evacuation and/or supply transport during emergencies. This paper presents statistical evaluations that geospatially characterize the influence of these causative factors on the potential for landslides. A methodology in a GIS environment for querying and analyzing the wide variety of data sources needed for these evaluations to characterize each major lithological unit is also presented. This work lays the foundation for performing regional seismic slope stability analysis and mapping to determine the vulnerability of these lifeline corridors during the next majpr earthquake event.