Abstract

Tidally controlled stick-slip discharge of a West Antarctic ice stream

Robert A. Bindschadler
Code 971, NASA Goddard Space Flight Center, Greenbelt, MD 20771

Matt A. King
School of Civil Engineering and Geosciences, University of Newcastle, Newcastle Upon Tyne, England, NE1 7RU

R. B. Alley
Department of Geosciences and EMS Environment Institute, Pennsylvania State University, University Park, PA 16802

S. Anandakrishnan
Department of Geosciences and EMS Environment Institute, Pennsylvania State University, University Park, PA 16802

Laurie Padman
Earth and Space Research, Seattle, WA 98102-3620




A major West Antarctic ice stream discharges by sudden and brief periods of very rapid motion paced by oceanic tidal oscillations of about one meter. Acceleration to speeds greater than one meter per hour and deceleration back to a stationary state occur in minutes or less. Slip propagates at approximately 88 m/sec, suggestive of a shear wave traveling within the subglacial till. A model of an episodically slipping friction-locked fault reproduces the observed quasi-periodic event timing, demonstrating an ice stream's ability to change speed rapidly and its extreme sensitivity to subglacial conditions and variations in sea level.



Contact Bob Bindschadler for further information on this research.




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