There’s a whole world trapped deep beneath Antarctica’s vast ice sheets. There are glaciers that reach nearly three miles high. There are rivers and lakes that are filled with life. There are mountain ranges. There are volcanoes.

And every once in a while, a massive volcanic eruption will punch through the ice. As far as we know, the volcanoes that dot Antarctica’s ridiculously-named “Executive Committee Range“ haven’t seen an eruption in around 8,000 years. But according to new research the area is stirring: observations of a series of earthquake swarms suggest that the magma is moving.

In 2010 and 2011, a team of researchers, led by Washington University graduate student Amanda Lough, detected bursts of seismic activity—at least 1,370 earthquakes centered deep beneath Antarctica’s Marie Byrd Land in the continent’s West Antarctic Ice Sheet. “We interpret the swarm events as deep long-period earthquakes based on their unusual frequency content. Such earthquakes occur beneath active volcanoes, are caused by deep magmatic activity and, in some cases, precede eruptions,” the scientists write in their study.

The sighting of the earthquake swarms isn’t a guarantee of an impending eruption, they say. But swarms have been seen in advance of eruptions before, like in 1991′s Mount Pinatubo eruption. The earthquakes are caused by the changes in pressure exerted on the subsurface rock as magma moves around, deep within the Earth.

If volcanic activity were to start, says Lough and her team, it would take a wildly powerful eruption to cut all the way to the surface—the ice in the area is more than a half-mile thick. Even a small eruption, though, could be important, as it would likely melt a bunch of the western ice sheet, contributing to sea level rise or creating a layer of water along the bottom of glaciers, making it easier for ice to slide into the sea.

More from Smithsonian.com:

Here’s What Antarctica Looks Like Under All The Ice

Ancient Climate Change Meant Antarctica Was Once Covered with Palm Trees

Antarctica Erupts!