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Basal Mechanics of Ice Streams: Insights from Stick-slip Motion of Whillans Ice Stream, West Antarctica

Lookup NU author(s): Professor Matt King

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Abstract

The downstream portion of Whillans Ice Stream, West Antarctica, moves primarily by stick-slip motion. The observation of stick-slip motion suggests that the bed is governed by velocity-weakening physics and that the basal physics is more unstable than suggested by laboratory studies. The stick-slip cycle of Whillans Ice Plain exhibits substantial variability in both the duration of sticky periods and in slip magnitude. To understand this variability, we modeled the forces acting on the ice stream during the stick phase of the stick-slip cycle. The ocean tides introduce changes in the rate at which stress is applied to the ice plain. Increased loading rates promote earlier failure and vice versa. Results show that the bed of Whillans Ice Stream strengthens over time (healing) during the quiescent intervals in the stick-slip cycle, with the bed weakening during slip events. The time-dependent strengthening of the ice plain bed following termination of slip events indicates that the strength of the bed may vary by up to 0.35 kPa during the course of a single day.

Publication metadata

Author(s): Winberry JP, Anandadrishnan S, Alley RB, Bindschadler R, King MA

Publication type: Article

Publication status: Published

Journal: Journal of Geophysical Research: Earth Surface

Year: 2008

Volume: 114

Issue: 1

Date deposited: 12/07/2010

ISSN (print): 0148-0227

Publisher: American Geophysical Union

URL: http://dx.doi.org/10.1029/2008JF001035

DOI: 10.1029/2008JF001035

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