Quakes hint at moving magma that could influence glacial flow
Quivers in the remote West Antarctic have all the hallmarks of volcanoes and magma under the ice, according to a study appearing November 17 in Nature Geoscience.
Volcanic activity in the continent’s crust could hasten the flow of its ice sheet to the ocean, scientists say.
Using 37 seismic stations, earth scientist Amanda Lough of Washington University in St. Louis and colleagues recorded hundreds of rumbles on the frozen continent in 2010 and 2011. The tremors’ frequencies and depths – between 25 and 40 kilometers below the ice — are similar to those recorded under active volcanoes in other parts of the world.
Though it’s unclear whether the quakes signal an impending eruption, the authors say that lava is not likely to burst through the continent’s thick ice sheet. But the churning of molten rock could thaw the sheet’s underside. Such heat could accelerate flow in the West Antarctic ice sheet, the authors say, which is already shrinking from warming ocean waters.
A. C. Lough et al. Seismic detection of an active subglacial magmatic complex in Marie Byrd Land, Antarctica. Nature Geoscience. November 17, 2013. doi:10.1038/ngeo1992.