Scientists record never-before-seen 'ice quakes' deep inside Greenland's frozen rivers

Sascha Pare
published 16 hours ago

Quakes recorded for the first time inside Greenland's biggest frozen river, the Northeast Greenland Ice Stream, suggest this river and others switch between moving jerkily and flowing like honey.



Researchers recorded ice quakes in the Greenland Ice Sheet by lowering a fiber-optic cable down a borehole. Pictured above is a tunnel that leads to the borehole. (Image credit: Andreas Fichtner/ETH Zurich)


In a first, researchers have recorded countless "ice quakes" that sporadically shake the Greenland Ice Sheet. These quakes may explain the jerky way that the island's frozen rivers move downstream toward the sea, the scientists say.

Researchers detected these quakes by lowering a fiber-optic cable into a 1.7-mile-deep (2.7 kilometers) borehole in the Northeast Greenland Ice Stream — Greenland's largest frozen river that serves as the main artery through which ice is discharged from the ice sheet's interior into the North Atlantic Ocean.

Similar to earthquakes, ice quakes are seismic events that can happen in ice when it fractures and two slabs grind against each other.

Ice quakes in Greenland have gone undetected until now because they are blocked from reaching the surface by a layer of volcanic particles buried 2,950 feet (900 meters) beneath the ice, the researchers said in a statement. These particles originated from a huge eruption of Mount Mazama, in what is now Oregon, about 7,700 years ago, they said.

More:
https://www.livescience.com/planet-earth/arctic/scientists-record-never-before-seen-ice-quakes-deep-inside-greenlands-frozen-rivers