Melting ice sheets can trigger massive earthquakes

March 15th, 2008 - 2:45 pm ICT by admin  

National Geographic

Washington, March 15 (ANI): A new study has indicated that melting ice sheets can release pent-up energy and trigger massive earthquakes.

According to a report in National Geographic News, as a result of global warming, ice sheets are melting worldwide, which is triggering off earthquakes.

For the study, the researches had taken into account a series of large earthquakes that had shook Scandinavia around 10,000 years ago, along faults that are now quiet.

The ancient earthquakes marched northward through Scandinavia as ice sheets retreated.

The timing of each earthquake roughly coincided with the melting of thick ice sheets from the last ice age in those same places. Researchers had suspected that the melting had triggered these earthquakes by releasing pressure that had built up in Earth’s crust.

Now, the new study, which is the first to use sophisticated computer models to simulate how ice sheets would affect the crust in the region, bolsters this scenario.

The study showed that earthquakes are suppressed in presence of the ice and promoted during melting of the ice,” said study leader Andrea Hampel of the Ruhr University Bochum in Germany.

Hampel and a colleague had earlier found evidence that the shrinkage of a huge lake at the end of the last ice age had triggered a series of large earthquakes in Utah. The new study shows this can happen even along faults that are normally quiet and are not prone to slip.

“With our new modeling technique, we can model faults themselves and directly compare the slip on the model fault to the slip on natural faults,” said Hampel.

The models showed that thick ice could weigh down the land, preventing a fault from slipping and thereby causing it to store up that energy.

The thicker the simulated ice sheetsfrom 325 to 6,500 feet (100 to 2,000 meters) thickthe more they suppressed earthquakes, and the bigger the earthquakes were after the ice sheets melted.

Since the amount of movement on the fault in the model matched the actual amount of slippage measured in the field, this supports the idea that the melting of ice sheets had triggered the earthquakes, said Hampel.

According to Hampel and colleagues, “The frequency of earthquakes should increase in the future if the ice continues to melt.”

“We expect that in Greenland and Antarctica, if they start rapidly losing lots of ice, you would expect at least some little earthquakes,” said Jeanne Sauber of NASA’s Goddard Space Flight Center in Greenbelt, Maryland. (ANI)

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