Glacial earthquakes help scientists measure iceberg production

April 11 (UPI) -- Researchers in France have found a way to measure iceberg production by analyzing glacial earthquakes.

Ice sheets and glaciers lose ice two ways: melting and calving. Calving is separation of large blocks of ice from coastal glaciers.

Scientists, with the help of advanced satellite technology, are getting much better at tracking melt rates, the thinning of glaciers and the outflow of melt water. But tracking calving with satellites is impossible.

When icebergs calve, the separation generates earthquakes that reverberate through the ice and can be felt a few hundred miles away.

To measure the separation of icebergs from Greenland's glaciers, scientists at CNRS and Paris Diderot University, analyzed glacial seismological data collected on the ice-covered island between 1993 and 2013. When scientists surveyed the decade-long data set, they found more than 500 calving-caused seismic patterns.

"This breakthrough in environmental seismology has made it possible to quantify Greenland glacial shrinkage through calving," scientists reported in a news release.

The new analysis of the seismic data suggests calving was responsible for 21 percent of Greenland's ice discharge and 6 percent of the Greenland mass loss. Between 1993 and 2013, 370 gigatons of ice was discharged into the Arctic Ocean as a result of calving.

"While calving production tends to stabilize in East Greenland," scientists reported in the journal Annals of Glaciology, "Western glaciers have released more and larger icebergs since 2010 and have become major contributors to Greenland dynamic discharge."