The 2016 Lamplugh rock avalanche, Alaska: deposit structures and emplacement dynamics

Supraglacial landslides result from the catastrophic failure of periglacial rock slopes and deposit large volumes of rock and ice onto the glacier surface. The most remarkable features of these landslides are their prominent long flowbands and a high mobility that exceeds that of their counterparts...

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Bibliographic Details
Published in:Landslides 2019-12, Vol.16 (12), p.2301-2319
Main Authors: Dufresne, A., Wolken, G. J., Hibert, C., Bessette-Kirton, E. K., Coe, J. A., Geertsema, M., Ekström, G.
Format: Article
Language:English
Subjects:
Agriculture
Avalanches
Catastrophic events
Civil Engineering
Debris
Deceleration
Digital Elevation Models
Dynamics
Earth and Environmental Science
Earth Sciences
Entrainment
Fault lines
Geography
Geological faults
Geology
Glacial drift
Glaciers
Landslides
Landslides & mudslides
Lobes
Mobility
Morphology
National parks
Natural Hazards
Offsets
Original Paper
Rock glaciers
Rocks
Sciences of the Universe
Seismic data
Seismological data
Slope
Slopes
Strike-slip faults
Surveys
Topography
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Summary:Supraglacial landslides result from the catastrophic failure of periglacial rock slopes and deposit large volumes of rock and ice onto the glacier surface. The most remarkable features of these landslides are their prominent long flowbands and a high mobility that exceeds that of their counterparts in other environments. Based on field surveys, high-resolution digital elevation models, and continuous seismic data, we show that the emplacement dynamics of the 2016 rock avalanche on Lamplugh Glacier were characterized by two distinct stages. During the first stage, the debris traveled about 5 km from the base of the slope. Clear long-period seismic signals during this stage record strong interactions of the rock avalanche debris with the ground, suggesting dynamic processes such as grain collisions and fragmentation. The second stage was essentially aseismic at long periods and dominated by low-friction sliding at slow deceleration rates. A higher density of flowbands and increased entrainment of snow from the runout path characterize the morphology of this second-stage distal deposition. Around the margins, lobes are offset by up to 400 m along major strike-slip faults, whereas within individual lobes, offsets between flowbands are much less pronounced (0 to
ISSN:1612-510X
1612-5118
DOI:10.1007/s10346-019-01225-4