Published In

Geophysical Research Letters

Document Type

Article

Publication Date

5-7-2018

Subjects

Landslides -- Oregon, Landslides -- Remote sensing, Optical radar, Landslides -- Forecasting, Debris avalanches

Abstract

Landslides reactivate due to external environmental forcing or internal mass redistribution, but the process is rarely documented quantitatively. We capture the three-dimensional, 1-m resolution surface deformation field of a transiently reactivated landslide with image correlation of repeat airborne lidar. Undrained loading by two debris flows in the landslide’s head, rather than external forcing, triggered reactivation. After that loading, the lower 2 km of the landslide advanced by up to 14 m in 2 years before completely stopping. The displacement field over those 2 years implies that the slip surface gained 1 kPa of shear strength, which was likely accomplished by a negative dilatancy-pore pressure feedback as material deformed around basal roughness elements. Thus, landslide motion can be decoupled from external environmental forcing in cases, motivating the need to better understand internal perturbations to the stress field to predict hazards and sediment fluxes as landscapes evolve.

Description

©2018. American Geophysical Union.

DOI

10.1029/2018GL077812

Persistent Identifier

https://archives.pdx.edu/ds/psu/25402

Available for download on Saturday, November 17, 2018

Included in

Geology Commons

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