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Tidally Controlled Stick-Slip Discharge of a West Antarctic Ice

2003; American Association for the Advancement of Science; Volume: 301; Issue: 5636 Linguagem: Inglês

10.1126/science.1087231

1095-9203

Robert Bindschadler, Matt A. King, Richard B. Alley, S. Anandakrishnan, Laurie Padman,

Geology and Paleoclimatology Research

A major West Antarctic ice stream discharges by sudden and brief periods of very rapid motion paced by oceanic tidal oscillations of about 1 meter. Acceleration to speeds greater than 1 meter per hour and deceleration back to a stationary state occur in minutes or less. Slip propagates at approximately 88 meters per second, 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.