Scientists learned that the massive earthquakes Greenland experiences every time it loses ice may help them track the pace at which the world’s largest island losses its precious ice sheets.
Scientists from the Columbia University ’s Lamont-Doherty Earth Observatory and Swansea University in the UK cracked open the mechanism behind Greenland’s glacial earthquakes.
The team explained that the earthquakes occur when a huge iceberg separates from a tidal glacier. As they splash into the water, the icebergs also give a push to the glacier backwards. The force of the impact is so strong that it generates a surface seismic wave that can be detected across the entire planet.
Researcher Meredith Nettles at the Columbia University said that the earthquakes can reach a magnitude of 5.2.
“Which is a pretty big earthquake,”
But scientists are concerned because these massive quakes are seven times more frequent than they were in the 1990s. They argued that their rate skyrocketed as the climate became warmer and more icebergs were released into the sea by the melting glaciers.
During their research, scientists used GPS trackers on the Helheim Glacier and monitored its calving edge with a camera. Additionally, they asked earthquake experts to track seismic activity in the area.
Nettles noted that the amount of ice Helheim Glacier currently loses is astronomical. Its calving glaciers contain around a gigaton of ice mass. The researcher equated that mass with the amount of ice we would obtain if we were to cover the entire National Mall with ice to an altitude about four times higher than the Washington monument.
Additionally, a calving glacier can reach 2 miles in length, so we shouldn‘t be surprised when such behemoth jolts the Earth while colliding with another huge body of ice.
The research team even conducted a simulation of what happens when an iceberg breaks off from the glacier. The model showed that in the first seconds the glacier stands vertically just like someone would cut a thick slice of bread. But a few moments later the glacier starts to capsize.
In the process, the top hits the glacier’s calving front, while its bottom rises to the surface leaving the iceberg to float flat for a few moments. The resulting force is so tremendous that it can push back the glacier inland and temporarily reverse its front flow generating a significant seismic activity.
A paper on the finding and calving icebergs’ dynamics was published Thursday in the journal Science.
Image Source: BC 25