Frictional Origin of Slip Events of the Whillans Ice Stream, Antarctica
Name
guerin_whillans_grl2021.pdf
Description
Published version
Size
3.96 MB
Format
Unknown
Checksum (MD5)
208257ed4fe55e4a48ea8c0f2eca0ae5
Author(s)
Guerin, Gauthier
Mordret, Aurelien
Rivet, Diane
Lipovsky, Bradley P.
Minchew, Brent M
Date Issued
June 2021
Journal
Geophysical Research Letters
Publisher
American Geophysical Union (AGU)
Version
Final published version
Abstract
Ice sheet evolution depends on subglacial conditions, with the ice-bed interface's strength exerting an outsized role on the ice dynamics. Along fast-flowing glaciers, this strength is often controlled by the deformation of subglacial till, making quantification of spatial variations of till strength essential for understanding ice-sheet contribution to sea-level. This task remains challenging due to a lack of in situ observations. We analyze continuous seismic data from the Whillans Ice Plain (WIP), West Antarctica, to uncover spatio-temporal patterns in subglacial conditions. We exploit tidally modulated stick-slip events as a natural source of sliding variability. We observe a significant reduction of the till seismic wave-speed between the WIP sticky-spots. These observations are consistent with a poroelastic model where the bed experiences relative porosity and effective pressure increases of >11% during stick-slips. We conclude that dilatant strengthening appears to be an essential mechanism in stabilizing the rapid motion of fast-flowing ice streams.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
Terms of Use
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
Persistent DSpace Link
DOI of Published Version
https://doi.org/10.1029/2021gl092950
