It’s not as peaceful as it looks under west Antarctica (Image: Michael Studinger/NASA) Radio waves reflected from the features beneath the ice show an undulating layer of ash (middle black line) above the craggy bedrock (bottom black line). The tremors occurred much deeper but the red circle shows their horizontal position. The black line at the top is the surface of the ice (Image: Blankenship and Young/Nature Geoscience)

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.


There are plenty of volcanoes jutting up from the Antarctic ice, most famously Mount Erebus. But while it was clear that there were also subglacial volcanoes, none of them were known to be active, says Amanda Lough of Washington University in St Louis, Missouri. “For the first time, we’re seeing evidence of activity right now.”

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

The tremors were deep, 25 to 40 kilometres 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.

Blast from beneath

“That area is known to have been active in the past,” says Hugh Corr of the British Antarctic Survey in Cambridge, UK, who wasn’t involved in the work. Back in 2008 he found traces of a subglacial eruption that took place around 2000 years ago.

By looking at the subsurface topography – collected using a plane that bounces a ground-penetrating radio waves off the underground features – Lough says the recent tremors happened under a rise in the bedrock, which protrudes about a kilometre above the surrounding rock, but isn’t high enough to stick out of the ice. She believes this may be the volcanic cone. Lough also detected a layer of ash trapped in the ice, probably from an eruption. Based on its depth, the ash seems to be 8000 years old.

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 kilometres every million years, Lough says.

The volcanoes are probably created by a tectonic rift running under west Antarctica, where Earth’s crust is being slowly pulled apart and molten rock is welling up from beneath. Similar geological activity is seen in the Rift Valley in Ethiopia. The volcano Lough found is on the edge of the rift. The presence of the rift means the area also experiences significant earthquakes, although the largest “megaquakes” are unlikely.

“In the early studies people thought Antarctica was aseismic,” says Lough. “It definitely isn’t. It’s a lot livelier than people assumed.”

Shifting ice

There’s no way to know when, or if, the buried volcano will erupt again. “I can’t put a date on when the next one’s going to happen,” says Lough. 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. “I don’t think it’s going to cause major ice sheet failure, but it’s going to be noticeable,” says Lough.

“It can suddenly pop, and that would have a huge effect [underground],” says Corr. But he says the low-level heat from the buried magma may be just as important in loosening the ice as the occasional big eruption.

The finding is another reminder that Antarctica’s thick ice sheets conceal a hidden world. A mountain range the size of the Alps, the Gamburtsevs, is buried under the ice of East Antarctica. There is also a vast plumbing system of channels and lakes, many of which probably contain life.

Journal reference: Nature Geoscience, DOI: 10.1038/ngeo1992