Distributed Acoustic Sensing (DAS) of Seismic Properties in a Borehole drilled on a Fast‐Flowing Greenlandic Outlet Glacier

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Type Article
Original languageEnglish
Article numbere2020GL088148
Number of pages10
JournalGeophysical Research Letters
Volume47
Issue number13
Early online date07 Jul 2020
DOI
Publication statusPublished - 16 Jul 2020
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Abstract

Distributed Acoustic Sensing (DAS) is a new technology in which seismic energy is detected, at high spatial and temporal resolution, using the propagation of laser pulses in a fibre‐optic cable. We show analyses from the first glaciological borehole DAS deployment to measure the englacial and subglacial seismic properties of Store Glacier, a fast‐flowing outlet of the Greenland Ice Sheet. We record compressional and shear waves in 1043 m‐deep vertical seismic profiles, sampled at 10 m vertical resolution, and detect a transition from isotropic to anisotropic ice at 84% of ice thickness, consistent with the Holocene‐Wisconsin transition. We identify subglacial reflections originating from the base of a 20 m‐thick layer of consolidated sediment and, from attenuation measurements, interpret temperate ice in the lowermost 100 m of the glacier. Our findings highlight the promising potential of DAS technology to constrain the seismic properties of glaciers and ice sheets.

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