Note to users. If you're seeing this message, it means that your browser cannot find this page's style/presentation instructions -- or possibly that you are using a browser that does not support current Web standards. Find out more about why this message is appearing, and what you can do to make your experience of our site the best it can be.

Published Online September 25, 2003
Science DOI: 10.1126/science.1088057

Reports

Submitted on June 16, 2003
Accepted on September 9, 2003

Glacial Earthquakes

Göran Ekström 1*, Meredith Nettles 1, Geoffrey A. Abers 2

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.

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 non-detection 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 30-60 seconds, about 15-30 times longer than for a regular tectonic earthquake of similar magnitude.


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
   Abstract »    Full Text »    PDF »
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
   Abstract »    Full Text »    PDF »
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
   Abstract »    Full Text »    PDF »


To Advertise     Find Products

Science. ISSN 0036-8075 (print), 1095-9203 (online)