Fracture propagation to the base of the Greenland Ice Sheet during supraglacial lake drainage
Fracture propagation to the base of the Greenland Ice Sheet during supraglacial lake drainage
Date
2008-02-20
Authors
Das, Sarah B.
Joughin, Ian
Behn, Mark D.
Howat, Ian M.
King, Matt A.
Lizarralde, Daniel
Bhatia, Maya P.
Joughin, Ian
Behn, Mark D.
Howat, Ian M.
King, Matt A.
Lizarralde, Daniel
Bhatia, Maya P.
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Abstract
Surface meltwater that reaches the base of an ice sheet creates a mechanism for the
rapid response of ice flow to climate change. The process whereby such a pathway
is created through thick, cold ice has not, however, been previously observed. We
describe the rapid (<2 hours) drainage of a large supraglacial lake down 980 m
through to the bed of the Greenland Ice Sheet initiated by water-driven fracture
propagation evolving into moulin flow. Drainage coincided with increased
seismicity, transient acceleration, ice sheet uplift and horizontal displacement.
Subsidence and deceleration occurred over the following 24 hours. The short-lived
dynamic response suggests an efficient drainage system dispersed the meltwater
subglacially. The integrated effect of multiple lake drainages could explain the
observed net regional summer ice speedup.
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Author Posting. © The Authors, 2008. This is the author's version of the work. It is posted here by permission of American Association for the Advancement of Science for personal use, not for redistribution. The definitive version was published in Science 320 (2008): 778-781, doi:10.1126/science.1153360.