Regularly Spaced (in time) Seismic Events Originating From Beneath David Glacier in the Transantarctic Mountain Range of Antarctica

Highly regular seismicity associated with the flow of David Glacier in the Transantarctic Mountains of Antarctica has been detected and analyzed. We used data from the Transantarctic Mountain Seismic Experiment (TAMSEIS) network, which consisted of 42 broadband seismometers deployed from November 2000 through December 2003. The seismic events recur regularly (approximately 20 min). Travel time measurements determined that the events originated from the base of David Glacier (approximately 2.3 km deep in this area). Low angle faulting determined from P-wave first motions indicate a fault strike of 185 degrees, which is normal to the flow of David Glacier. The events are likely caused by an asperity beneath David Glacier that regularly releases stress, which is accumulated as David glacier flows over the asperity. The regularity of the events is steady due to the constant and homogenous driving stress of the overlying ice as well as the weakness of the bed. Models of earthquake source regions that include a few asperities within a weak active fault are thought to display this behavior. The regularly recurring ruptures beneath David Glacier provide a field based study of stick slip faulting, on a time scale in which large numbers of events can be recorded within relatively short monitoring period.