Title Sudden increase in tidal response linked to calving and acceleration at a large Greenland outlet glacier
Author de Juan, J.; Elˇsegui, P.; Nettles, M.; Larsen, T.B.; Davis, J.L.; Hamilton, G.S.; Stearns, L.A.; Andersen, M.L.; Ekstr÷m, G.; Ahlstrom, A.P.; Stenseng, L.; Khan, S.A.; Forsberg, R.
Author Affil de Juan, J., Consejo Superior de Investigaciones Cientificas, Institute for Space Sciences, Barcelona, Spain. Other: Lamont-Doherty Earth Observatory; Geological Survey of Denmark and Greenland, Denmark; Harvard-Smithsonian Center for Astrophysics; University of Maine; University of Kansas; University of Copenhagen, Denmark; National Space Institute, Denmark
Source Geophysical Research Letters, 37(12), Citation L12501. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276
Publication Date 2010
Notes In English. 31 refs. GeoRef Acc. No: 310425
Index Terms calving; geodesy; glacial geology; glaciers; icequakes; littoral zone; melting; tides; Greenland; Arctic region; coastal environment; dynamics; Global Positioning System; Helheim Glacier; intertidal environment; ocean circulation; sea-level changes; tidal response
Abstract 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.
URL http://hdl.handle.net/10.1029/2010GL043289
Publication Type journal article
Record ID 65007172