Scientists funded by the National Science Foundation (NSF) have observed "swarms" of seismic activity--thousands of events in the same locations, sometimes dozens in a single day--between January 2010 and March 2011, indicating current volcanic activity under the massive West Antarctic Ice Sheet (WAIS).
Previous studies using aerial radar and magnetic data detected the presence of subglacial volcanoes in West Antarctica, but without visible eruptions or seismic instruments recording data, the activity status of those systems ranged from extinct to unknown. However, as Amanda Lough, a doctoral candidate at Washington University in St. Louis, points out, "Just because we can't see ...below the ice, doesn't mean there's not something going on there."
"This [study] is saying that we have seismicity, which means [this system] is active right now," according to Lough. "This is saying that the magmatic chamber is still alive; that there is magma that is moving around in the crust."
Lough published her discovery in this week's issue of Nature Geoscience along with her advisor Douglas Wiens, a professor of earth and planetary sciences at Washington University in St. Louis, and a team of co-authors.
NSF has a presidential mandate to manage the U.S. Antarctic Program, through which it coordinates all U.S. science on the Southernmost continent and in the Southern Ocean and the logistical support which makes the science possible.
The characteristics of the seismic events, including the 25- to 40-kilometer (15- to 25-mile) depth at which they occurred, the low frequency of the seismic waves, and the swarm-like behavior rule out glacial and tectonic sources, but are typical of deep long-period earthquakes. Deep long-period earthquakes indicate active magma moving within the Earth's crust and are most often associated with volcanic activity.
The two swarms of seismic activity were detected by instruments deployed to
|Contact: Peter West|
National Science Foundation