In-situ Measurements of Stick-Slip Motion at the Bed of an Alpine Glacier
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Date
2018
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Conference Poster
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yes
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Abstract
Until recently, observations of sudden frictional processes at the bed of glaciers were limited to monitoring form the glacier surface. We study these processes causing stick-slip motion with a new approach that was applied the first time in a field campaign in summer 2018:
We carried out the first in-situ measurements of an active seismogenic fault at a bi- material interface beneath a glacier. Enabled by guided hot water drilling, we targeted borehole experiments to specific glacier bed regions where spatially limited microseismic stick-slip sliding happens and combine them with the recordings of a high-densitiy network of seismometers at the glacier surface.
From the various measurements we can determine the subglacial water- and thus pore pressure evolution and its effect on the fault stability. Futhermore the in-situ borehole measurements enable us to study material properties such as the till and ice characteristics within the stick-slip asperities and compare them to off-site reference measurements in seimically non-active regions of the glacier bed. Finally from acceleration, ice deformation measurements, and borehole camera videos from the glacier bed, we can estimate the amount of aseismic and co-seismic sliding, which cannot be obtained remotely from the ice surface.
Summed up, with our in-situ measurements of an seismogenically active strike-slip fault beneath an alpine glacier, we open a unique posibility for studying seismogenic stick-slip motion at a bi-material interface in a natural environment.
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published
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ETH Zurich, Laboratory of Hydraulics, Hydrology and Glaciology (VAW), Glacier Seismology Group
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Meet & Share Your Research Day at D-BAUG, ETH Zurich
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Subject
Glaciology; glacier seismology; stick-slip dynamics; Glacier dynamics
Organisational unit
09558 - Walter, Fabian (ehemalig) / Walter, F. ((former))