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Transient Reactivation of a Deep‐Seated Landslide by Undrained Loading Captured With Repeat Airborne and Terrestrial Lidar
Author(s) -
Booth Adam M.,
McCarley Justin,
Hinkle Jason,
Shaw Susan,
Ampuero JeanPaul,
Lamb Michael P.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl077812
Subject(s) - landslide , geology , debris , geomorphology , slip (aerodynamics) , forcing (mathematics) , landslide classification , lidar , displacement field , landslide mitigation , geotechnical engineering , pore water pressure , remote sensing , atmospheric sciences , physics , thermodynamics , oceanography , finite element method
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.