It's a land of ice and fire. For the first time, an active volcano has been spotted rumbling away under the ice sheet of west Antarctica. It's further evidence that the frozen continent is anything but still. The heat from the volcano could speed up the demise of Antarctica's fragile ice sheet.

 

Thanks to a network of seismometers that have been installed in Marie Byrd Land in western Antarctica over the last six years, the seismometers have since then detected two swarms of tremors: one in January and February 2010, and the other in March 2011.

 

The tremors were deep, 25 to 40 kilometers down, so they couldn't have been the result of the ice moving. What's more, they had a fairly low frequency, between 2 and 4 Hertz, suggesting they were not caused by an earthquake. However, shifting magma does produce low, rumbling tremors.

 

By looking at the subsurface topography, the recent tremors happened under a rise in the bedrock, which protrudes about a kilometer above the surrounding rock, but isn't high enough to stick out of the ice. This may be the volcanic cone.

 

The volcano is close to a string of mountains called the Executive Committee Range, which were once volcanoes themselves. The volcanic activity seems to be moving south by about 9.6 kilometers every million years.

 

There's no way to know when, or if, the buried volcano will erupt again. But if it does go off, the molten rock will melt the base of the ice, sending liquid water flowing under nearby ice streams. These would start moving faster as a result, dumping more ice into the sea, and causing sea levels to rise a bit faster.

 

The finding is another reminder that Antarctica's thick ice sheets conceal a hidden world.