Pity poor Antarctica: already shedding its land (but not its sea) ice, it's now been found to conceal a volcano of some considerable size beneath its frosty coating.

Like a nicotine addict making a desperate attempt to hide in an airline toilet, this smoker had itself hidden – but instead of a couple of centimetres of door, its presence was concealed underneath the glaciers in the vicinity of Mount Sidley.

The subsurface volcano turned up in a study of the Executive Committee Range (don't blame The Register for the naming conventions), part of Marie Byrd Land (which doesn't show itself above the surface of the ice).

A group of American researchers took seismological data from the area between 2006 and 2010, and came up with two conclusions: the sub-glacial volcanic activity that formed features like the Executive Committee Range is still taking place now – and it's moving southwards at the rate of 9.6 km, every million years.

In the study published in Nature Geoscience (abstract here), the researchers say they detected swarms of earth tremors between 25 km and 40 km deep, in February 2010 and March 2011.

The tremors were too deep to have been caused by glacial movement, and the waves they gave off – at between 2 and 4 Hertz – are too low in frequency to be associated with tectonic movement. That left shifting magma as the most likely explanation, according to New Scientist.

The seismological data was combined with radar mapping to discover the topology in the area. This also turned up a layer of volcanic ash embedded in the ice from an eruption of Mount Waesche sometime in the last 8,000 years.

The scientists note that a big eruption caused by this activity would have a “noticeable” global impact, according Amanda Lough of Washing University, St Louis. A sudden eruption would appear as a slight increase in sea level rise. ®