Nucleation and seismic tremor associated with the glacial earthquakes of Whillans Ice Stream, Antarctica

J. Paul Winberry, S. Anandakrishnan, D. A. Wiens, and R. B. Alley

Geophysical Research Letters (28 January 2013)

DOI: 10.1002/grl.50130

The ability to monitor transient motion along faults is critical to improving our ability to understand many natural phenomena such as landslides and earthquakes. Here, we usedata from a GPS and seismometer network that were deployed to monitor the regularly repeating glacial earthquakes of Whillans Ice Stream, West Antarctica to show that a unique pattern of precursory slip precedes complete rupture along the bed of the ice stream. Additionally, we show that rupture can be independently tracked by increased levels of microseismic activity, including harmonic tremor, that are coincident with the onset of slip at any location, thus providing a remote means of monitoring stress and rupture propagation during the glacial earthquakes.

keywords: Keyword; harmonic tremor; glacial earthquakes; ice stream; stick-slip nucleation; 0730 Ice streams; 0726 Ice sheets; 7215 Earthquake source observations

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