Icy Earthquakes Can Help Scientists Track Shrinking Glaciers
Joseph Dussault
The Christian Science Monitor/Alaska Dispatch NewsJune 28, 2015
In the past 20 years, Greenland’s mysterious glacial earthquakes have become seven times more common. Now, scientists finally understand why they occur.
After in-depth monitoring of Greenland’s Helheim Glacier, researchers discovered that falling ice chunks could actually force the glacier backward. From there, a rapid change in water pressure could cause serious seismic events, like tsunami waves and moderate earthquakes. Their findings were published Thursday in Science magazine.
Glacial earthquakes are usually associated with “calving,” or the splitting of ice from large glaciers. As the ice fragments tumble into the ocean, they are sometimes accompanied by violent rumbling. But until now, scientists did not understand why calving caused such a thunderous reaction on solid ground.
For 55 days, Meredith Nettles and colleagues used GPS sensors and cameras to monitor the Helheim Glacier. They found that the force of calving ice was enough to push back against the glacier.
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