Example of a joint seismological and geodetic study of a glacier

Multidisciplinary study of the David Glacier, South Victoria Land

Ice streams play a major role in ice mass balance and global sea level. Understanding the behavior of a major ice stream such as the David Glacier provides insights into ice dynamics and the stability of polar ice caps. In 2005/06 a seismological and geodetic instruments were deployed around the David Glacier.

Fig. 1 Shows the locations of the seismic and geodetic stations in the vicinity of the David Glacier

The deployment followed on from a similar investigation in 2003/04. During the two experiments, about 200 low magnitude events where detected originating from the ice-rock interface at the base of the glacier. Basal events recorded in 03/04 (shown as red stars in the diagram below) cluster around a point near the top of the fast-flowing region of the glacier. This indicates an asperity, a 'sticking point' which temporarily anchors the ice stream, then fails, resulting in an earthquake. Interestingly, none of the 2005/06 events (green stars in the diagram below) were located at the 03/04 asperity, suggesting that controls on the glacier have changed in a short, two year, time frame.

Fig. 2 Location of seismicity recorded in 03/04 (red stars) and 05/06 (green stars)