2007-09-10

Melting ice cap triggering earthquakes in Greenland

As a follow up to yesterday's post regarding an ice-free Arctic, there is this regarding the land-bound ice of Greenland melting so fast that it is now starting to cause earthquakes.

The Guardian reports that the Melting ice cap triggering earthquakes:

The Greenland ice cap is melting so quickly that it is triggering earthquakes as pieces of ice several cubic kilometres in size break off.

Scientists monitoring events this summer say the acceleration could be catastrophic in terms of sea-level rise and make predictions this February by the Intergovernmental Panel on Climate Change far too low.

...

He had flown over the Ilulissat glacier and "seen gigantic holes in it through which swirling masses of melt water were falling. I first looked at this glacier in the 1960s and there were no holes. These so-called moulins, 10 to 15 metres across, have opened up all over the place. There are hundreds of them."

This melt water was pouring through to the bottom of the glacier creating a lake 500 metres deep which was causing the glacier "to float on land. These melt-water rivers are lubricating the glacier, like applying oil to a surface and causing it to slide into the sea. It is causing a massive acceleration which could be catastrophic."

The glacier is now moving at 15km a year into the sea although in surges it moves even faster. He measured one surge at 5km in 90 minutes - an extraordinary event.

Veli Kallio, a Finnish scientist, said the quakes were triggered because ice had broken away after being fused to the rock for hundreds of years. The quakes were not vast - on a magnitude of 1 to 3 - but had never happened before in north-west Greenland and showed potential for the entire ice sheet to collapse.

Dr Corell said: "These earthquakes are not dangerous in themselves but the fact that they are happening shows that events are happening far faster than we ever anticipated."

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