Journal article
Sudden increase in tidal response linked to calving and acceleration at a large Greenland outlet glacier
Large calving events at Greenland's largest outlet glaciers are associated with glacial earthquakes and near-instantaneous increases in glacier flow speed. At some glaciers and ice streams, flow is also modulated in a regular way by ocean tidal forcing at the terminus. At Helheim Glacier, analysis of geodetic data shows decimeter-level periodic position variations in response to tidal forcing.
However, we also observe transient increases of more than 100% in the glacier's responsiveness to such tidal forcing following glacial-earthquake calving events. The timing and amplitude of the changes correlate strongly with the step-like increases in glacier speed and longitudinal strain rate associated with glacial earthquakes.
The enhanced response to the ocean tides may be explained by a temporary disruption of the subglacial drainage system and a concomitant reduction of the friction at the ice-bedrock interface, and suggests a new means by which geodetic data may be used to infer glacier properties.
Language: | English |
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Year: | 2010 |
ISSN: | 19448007 and 00948276 |
Types: | Journal article |
DOI: | 10.1029/2010GL043289 |
ORCIDs: | Stenseng, Lars , Khan, Shfaqat Abbas and Forsberg, René |