Scientists have discovered that glaciers can move rapidly backward and downward, causing what is called glacial earthquakes which until now have been poorly understood.
The team of UK and US researchers say the backward movement happens during some calving events when an iceberg breaks off into the ocean.
This insight will enable scientists to measure glacier calving remotely and will improve the reliability of models to predict future sea-level rises in a warming climate.
The research, gathered by using GPS monitors on the Helheim Glacier in Greenland, is published in the journal Science Express.
Swansea University’s Professor Tavi Murray, lead author of the study, says: “We were really surprised to see the glacier flowing backwards in our GPS data. The motion happens every time a large iceberg is calved and a glacial earthquake is produced. A theoretical model for the earthquakes and the laboratory experiments have allowed us to explain the backwards and downwards movement.”
The Greenland Ice Sheet is an important contributor to global sea-level and nearly half of the ice sheet’s annual mass loss occurs through the calving of icebergs to the ocean.
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