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Analysis of glacial earthquakes

Tsai, Victor C. and Ekström, Göran (2007) Analysis of glacial earthquakes. Journal of Geophysical Research F, 112 (F3). Art. No. F03S22. ISSN 0148-0227. doi:10.1029/2006JF000596.

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In 2003, Ekström et al. reported on the detection of a new class of earthquakes that occur in glaciated regions, with the vast majority being in Greenland. The events have a characteristic radiation pattern and lack the high-frequency content typical of tectonic earthquakes. It was proposed that the events correspond to large and sudden sliding motion of glaciers. Here we present an analysis of all 184 such events detected in Greenland between 1993 and 2005. Fitting the teleseismic long-period surface waves to a landslide model of the source, we obtain improved locations, timing, force amplitudes, and force directions. After relocation, the events cluster into seven regions, all of which correspond to regions of very high ice flow and most of which are named outlet glaciers. These regions are Daugaard Jensen Glacier, Kangerdlugssuaq Glacier, Helheim Glacier, the southeast Greenland glaciers, the northwest Greenland glaciers, Rinks Isbrae, and Jakobshavn Isbrae. Event amplitudes range from 0.1 to 2.0 × 10^(14) kg m. Force directions are consistent with sliding in the direction of glacial flow over a period of about 50 s. Each region has a different temporal distribution of events. All glaciers are more productive in the summer, but have their peak activity in different months. Over the study period, Kangerdlugssuaq has had a constant number of events each year, whereas Jakobshavn had most events in 1998–1999, and the number of events in Helheim and the northwest Greenland glaciers has increased substantially between 1993 and 2005. The size distribution of events in Kangerdlugssuaq is peaked above the detection threshold, suggesting that glacial earthquakes have a characteristic size.

Item Type:Article
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Tsai, Victor C.0000-0003-1809-6672
Additional Information:© 2007 by the American Geophysical. Received 12 June 2006; revised 27 October 2006; accepted 22 November 2006; published 14 April 2007. We thank R. Anderson, T. Murray, S. Anandakrishnan, and an anonymous reviewer for helpful comments. This research was supported by a National Science Foundation Graduate Fellowship (VCT) and National Science Foundation grants EAR-0207608 and OPP-0352276. The seismic data were collected and distributed by the Incorporated Research Institutions for Seismology and the U.S. Geological Survey.
Group:Seismological Laboratory
Funding AgencyGrant Number
NSF Graduate Research FellowshipUNSPECIFIED
Issue or Number:F3
Record Number:CaltechAUTHORS:20140620-153346884
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Official Citation:Tsai, V. C., and G. Ekström (2007), Analysis of glacial earthquakes, J. Geophys. Res., 112, F03S22, doi:10.1029/2006JF000596
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:46407
Deposited By: Tony Diaz
Deposited On:23 Jun 2014 19:55
Last Modified:10 Nov 2021 17:25

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