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Sudden increase in tidal response linked to calving and acceleration at a large Greenland outlet glacier
Author(s) -
de Juan Julia,
Elósegui Pedro,
Nettles Meredith,
Larsen Tine B.,
Davis James L.,
Hamilton Gordon S.,
Stearns Leigh A.,
Andersen Morten L.,
Ekström Göran,
Ahlstrøm Andreas P.,
Stenseng Lars,
Khan S. Abbas,
Forsberg René
Publication year - 2010
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2010gl043289
Subject(s) - geology , glacier , ice calving , glacial period , ice stream , tidewater glacier cycle , geomorphology , forcing (mathematics) , glacier ice accumulation , climatology , cryosphere , sea ice , pregnancy , lactation , biology , genetics
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.