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Seismological Aspects of the December 2004 Great Sumatra-Andaman Earthquake

Kanamori, Hiroo (2006) Seismological Aspects of the December 2004 Great Sumatra-Andaman Earthquake. Earthquake Spectra, 22 (S3). S1-S12. ISSN 8755-2930. doi:10.1193/1.2201969.

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The 2004 Great Sumatra-Andaman earthquake had an average source duration of about 500 sec. and a rupture length of 1,200–1,300 km. The seismic moment, M0, determined with a finite source model, was 6.5×1022 N-m, which corresponds to Mw=9.18. Allowing for the uncertainties in the current M0 determinations, Mw is in the range of 9.1 to 9.3. The tsunami magnitude Mt is 9.1, suggesting that the overall size of the tsunami is consistent with what is expected of an earthquake with Mw=9.1 to 9.3. The short-period body-wave magnitude m-hatb is 7.25, which is considerably smaller than that of large earthquakes with a comparable Mw. The m-hatb versus Mw relationship indicates that, overall, the Great Sumatra-Andaman earthquake is not a tsunami earthquake. The tectonic environment of the rupture zone of the Great Sumatra-Andaman earthquake is very different from that of other great earthquakes, such as the 1960 Chile and the 1964 Alaska earthquakes. This difference may be responsible for the unique source characteristics of this earthquake. The extremely large size of the Great Sumatra-Andaman earthquake is reflected in the large amplitude of the long-period phase, the W phase, even in the early part of the seismograms before the arrival of the S wave. This information could be used for various early warning purposes.

Item Type:Article
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Kanamori, Hiroo0000-0001-8219-9428
Additional Information:©2006 Earthquake Engineering Research Institute (Received 6 December 2005; accepted 11 April 2006) The preparation of this manuscript was done while I was visiting at the Disaster Prevention Research Institute, Kyoto University, under the support of the Eminent Scientists Award Program of the Japan Society of Promotion of Science. We used the Global Seismic Network seismograms of the Incorporated Research Institutions for Seismology.
Subject Keywords:seismology; earthquakes; seismic waves
Issue or Number:S3
Record Number:CaltechAUTHORS:KANes06
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:6714
Deposited By: Archive Administrator
Deposited On:19 Dec 2006
Last Modified:08 Nov 2021 20:36

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