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Originally published in Science Express on 25 September 2003
Science 24 October 2003:
Vol. 302. no. 5645, pp. 622 - 624
DOI: 10.1126/science.1088057
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Reports

Glacial Earthquakes

Göran Ekström,1* Meredith Nettles,1 Geoffrey A. Abers2

We have detected dozens of previously unknown, moderate earthquakes beneath large glaciers. The seismic radiation from these earthquakes is depleted at high frequencies, explaining their nondetection by traditional methods. Inverse modeling of the long-period seismic waveforms from the best-recorded earthquake, in southern Alaska, shows that the seismic source is well represented by stick-slip, downhill sliding of a glacial ice mass. The duration of sliding in the Alaska earthquake is 30 to 60 seconds, about 15 to 30 times longer than for a regular tectonic earthquake of similar magnitude.

1 Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, MA 02138, USA.
2 Department of Earth Sciences, Boston University, 685 Commonwealth Avenue, Boston, MA 02215, USA.

* To whom correspondence should be addressed. E-mail: ekstrom{at}seismology.harvard.edu

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THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Moment Tensor Inversions of Icequakes on Gornergletscher, Switzerland.
F. Walter, J. F. Clinton, N. Deichmann, D. S. Dreger, S. E. Minson, and M. Funk (2009)
Bulletin of the Seismological Society of America 99, 852-870
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Shallow-conduit dynamics at Stromboli Volcano, Italy, imaged from waveform inversions.
B. Chouet, P. Dawson, and M. Martini (2008)
Geological Society, London, Special Publications 307, 57-84
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Global Detection and Location of Seismic Sources by Using Surface Waves.
G. Ekstrom (2006)
Bulletin of the Seismological Society of America 96, 1201-1212
   Abstract »    Full Text »    PDF »
Subglacial bedrock welding associated with glacial earthquakes.
M. Bestmann, A.H.N. Rice, F. Langenhorst, B. Grasemann, and F. Heidelbach (2006)
Journal of the Geological Society 163, 417-420
   Abstract »    Full Text »    PDF »
Seasonality and increasing frequency of Greenland glacial earthquakes..
G. Ekstrom, M. Nettles, and V. C. Tsai (2006)
Science 311, 1756-1758
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