There are massive slow moving “ice quakes” roaming across Antarctica. The quakes are shaking the “Whillans Ice Stream, a glacier 100 kilometers across and 1 kilometer thick, which flows from the ice sheet’s interior.”

“The reason that it doesn’t rattle the whole continent is that it’s a very slow event,” says Sridhar Anandakrishnan, a glaciologist at Pennsylvania State University in State College, who made the discovery along with Douglas Wiens, a seismologist at Washington University in St. Louis, Missouri. Normal earthquakes release their energy over a few seconds, but the Whillans’s shaking unfolds over 20 minutes.

Wiens first noticed the ice quakes 3 years ago as he analyzed data from 43 seismic sensors across Antarctica. Hoping for faint signals that would help him pinpoint previously unknown faults, he was instead greeted by booming vibrations from the same spot in West Antarctica.

(via scienceNOW)