London, March 12 : A computer model has shown that though earthquakes happen less often in areas covered by ice caps, they come back on a bigger scale when the ice melts.
According to a report in New Scientist, Andrea Hampel at Ruhr University in Bochum, Germany, and colleagues developed the new computer model.
The idea for the model came about when the researchers wondered why Scandinavia experienced a surge in tectonic activity around 9000 years ago, whereas few earthquakes occur there today.
They realised that the earthquake flurry coincided with the melting of the Fennoscandian ice sheet, which blanketed the area in the last ice age.
To discover why, they devised a model to test how geological faults respond when buried beneath several hundred metres of ice. They found that the vertical stress placed on the Earth's crust by a heavy ice sheet can suppress many types of fault from slipping and causing a quake.
Though the faults are pinned down for a time, stresses in the crust continue to build, so when the ice melts, earthquakes occur more strongly and more frequently.
According to Hampel, this has already been observed in Alaska, and Greenland and Antarctica could experience more earthquakes in the future as their ice sheets disappear.