Creep rupture at depth in a cold ice sheet [10]

Abstract

THE mechanism by which stress is released in intermediate and deep focus earthquakes and the physics of tectonic processes are of particular interest to Earth scientists. As a way of understanding such phenomena it would be valuable to have a relatively small scale tectonic system duplicating the processes taking place within the Earth. Several authors1-3 have speculated that processes operating within glaciers and ice sheets are analogous to those in the Earth. Experimental evidence has not supported the hypothesis of an Earth glacier equivalence, especially in terms of identifying faulting at depth within glaciers. A seismic survey made of a valley glacier in Canada4 found no deep ice events. However, evidence of the existence of discrete shear planes within the Antarctic Ice Sheet5 and evidence described here relating to the Greenland Ice Sheet, indicate that faulting takes place at depth in cold ice sheets. © 1978 Nature Publishing Group.