Reverse glacier motion during iceberg calving and the cause of glacial earthquakes

T. Murray*, M. Nettles, N. Selmes, L. M. Cathles, J. C. Burton, T. D. James, S. Edwards, I. Martin, T. O'Farrell, R. Aspey, I. Rutt, T. Baugé

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Nearly half of Greenland'smass loss occurs through iceberg calving, but the physical mechanisms operating during calving are poorly known and in situ observations are sparse. We show that calving at Greenland's Helheim Glacier causes a minutes-long reversal of the glacier's horizontal flow and a downward deflection of its terminus. The reverse motion results from the horizontal force caused by iceberg capsize and acceleration away from the glacier front. The downward motion results from a hydrodynamic pressure drop behind the capsizing berg, which also causes an upward force on the solid Earth. These forces are the source of glacial earthquakes, globally detectable seismic events whose proper interpretation will allow remote sensing of calving processes occurring at increasing numbers of outlet glaciers in Greenland and Antarctica.

Original languageEnglish (US)
Pages (from-to)305-308
Number of pages4
JournalScience
Volume349
Issue number6245
DOIs
StatePublished - Jul 17 2015

ASJC Scopus subject areas

  • General

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