In the same period, Lake Conway filled with an additional 1.2 cubic kilometres (1.2 trillion litres) of water.

BBC: Satellite images reveal the changes in volume of water

The impact that created the Malaren crater (which happened about a billion years ago) fragmented 250 cubic kilometres of rock.

ECONOMIST: Geothermal energy

For example, a feature known as Lake Englehardt took just under three years to empty two cubic kilometres (2 trillion litres) of water.

BBC: Satellite images reveal the changes in volume of water

The shape of the polar cap indicates that it is composed primarily of water ice, with a volume of 1.2 million cubic kilometres.

BBC: By BBC News Online Science Editor Dr David Whitehouse

So though the total volume of the eruption, put at about 0.14 cubic kilometres, is low, the amount of ash capable of travelling long distances is high.

ECONOMIST: Volcanoes and air travel: Small eruption in Iceland | The