Slip, Slide, Shake

GPS, seismic data yield clues about surging Antarctic glacier

Analyses of data gathered by Global Positioning System equipment atop one of Antarctica’s largest and most dynamic glaciers and by seismometers nearby suggest that friction in just one small area beneath the broad glacier regularly halts the ice’s lurching march to the sea.

Many of Antarctica’s largest ice streams — the megaglaciers that carry most of the ice draining off the continent — move at an irregular pace, first sticking in place, then surging ahead (SN: 3/31/07, p.