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Ross Ice Shelf Displacement and Elastic Plate Waves Induced by Whillans Ice Stream Slip Events
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  • Douglas A Wiens,
  • Richard C. Aster,
  • Andrew A. Nyblade,
  • Peter D Bromirski,
  • Peter Gerstoft,
  • Ralph A. Stephen
Douglas A Wiens
Washington University

Corresponding Author:[email protected]

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Richard C. Aster
Colorado State University
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Andrew A. Nyblade
Pennsylvania State University
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Peter D Bromirski
SIO/UCSD
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Peter Gerstoft
University of California, San Diego
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Ralph A. Stephen
WHOI
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Abstract

Ice shelves are assumed to flow steadily from their grounding lines to the ice front. We report the detection of ice-propagating extensional Lamb (plate) waves accompanied by pulses of permanent ice shelf displacement observed by co-located GNSS receivers and seismographs on the Ross Ice Shelf. The extensional waves and associated ice shelf displacement are produced by tidally triggered basal slip events of the Whillans Ice Stream, which flows into the ice shelf. The propagation velocity of 2800 m/s is intermediate between shear and compressional ice velocities, with velocity and particle motions consistent with predictions for extensional Lamb waves. During the passage of the Lamb waves the entire ice shelf is displaced about 60 mm with a velocity more than an order of magnitude above its long-term flow rate. Observed displacements indicate a peak dynamic strain of 10-7, comparable to that of earthquake surface waves that trigger ice quakes.
12 Feb 2024Submitted to ESS Open Archive
15 Feb 2024Published in ESS Open Archive