Earth sometimes shivers beneath thick blankets of ice

From San Francisco, at a meeting of the American Geophysical Union

New analyses of old seismic data have unveiled a previously unrecognized type of earthquake–quakes created by brief surges of massive glaciers.

When fault zones slip, they emit most of their stored energy as high-frequency ground motions, so that’s the type of vibrations that scientists typically monitor to detect earthquakes, says Göran Ekström, a geophysicist at Harvard University.