Breaking Glaciers Cause Icy Earthquakes!

Researchers track massive ice loss through the help of glacial quakes. Researchers have noticed that the cause of the quakes is due to the rapid movement (backward and downward) of the glaciers after an iceberg breaks off into the ocean.

The Greenland ice sheet is an important contributor to the global sea level rise; therefore it is very important to study its behavior. Up till now glacial earthquakes have been poorly understood.

Researchers have witnessed a sevenfold increase in glacial quakes over a span of two decades. These glaciers have been moving towards the north, meaning that there has been a massive loss from the ice sheet through calving, a piece that breaks off and separates.

“Our new understanding is a crucial step toward developing tools to remotely measure the mass loss that occurs when icebergs break off ice sheets,” said L. Mac Cathles, co-author of the new study, in a news release.

“Combining field observations with laboratory measurements from scaled-model calving experiments provided insights into the dynamics of calving and glacial earthquakes that would not have otherwise been possible.”

In the summer of 2013, researchers installed a wireless network of Global Positioning System devices on the chaotic surface of Helheim Glacier, is a flow of ice that originates from the much larger Greenland ice Sheet, to measure velocity and displacement glacier surface.

Tavi Murray, lead author of the study and Polar Medal award winner, expressed her surprise on seeing the glacier flowing backwards on the GPS data. The motion was noticed to happen every time a large iceberg is calved and a glacial earthquake is produced.

A theoretical model for the earthquake and the laboratory experiments allowed researchers to explain the backward and downward movement.

These findings reveal a little more about glacial behavior. Researchers have found a chance to gain better estimates in the future by measuring calving events and their contribution to sea-level change.

The findings are published in the journal Science.


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