Kanamori, Hiroo (2006) The Radiated Energy of the 2004 Sumatra-Andaman Earthquake. In: Earthquakes: Radiated Energy and the Physics of Faulting. Geophysical Monograph Series (170). American Geophysical Union , Washington, DC, pp. 59-68. ISBN 978-0-87590-435-1 http://resolver.caltech.edu/CaltechAUTHORS:20110603-090304573
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We use several independent methods to estimate the radiated energy E_R of the Sumatra-Andaman earthquake (M_w=9.0 to 9.3), and investigate whether the difference in the rupture patterns between north and south is reflected in the difference in the energy budget. First, we used a finite source model and estimated E_R to be 1.38 x 10^(17) J for a frequency band f (frequency) ≤ 0.1 Hz. Since this method is relatively free from many assumptions commonly made in energy estimation, this value is considered robust. To estimate E_R for a frequency band 0.1 ≤ f ≤ 1 Hz, we used a frequency-domain analysis and obtained E_R = 1.6 x 10^(17) J for this frequency band. This estimate is somewhat uncertain because of the energy attenuation during propagation and the effect of the near-source structure. We also estimated E_R relative to the 2001 Bhuj, India, earthquakes for which a reliable estimate of E_R has been obtained. The total E_R thus estimated is 3.0 x 10^(17) J. The energy-moment ratio, 0.46 x 10^(-5), is slightly smaller than that for other large subduction-zone earthquakes. The radiation efficiency defined by η_R = (2µ /Δr)(E_R/M_0) (µ=rigidity, M_0=seismic moment, Δr =static stress drop) is 0.16 which is smaller than that of many large earthquakes, and is between the values of regular earthquakes and slow tsunami earthquakes. The values of η_R for the Nicobar segment, the Nicobar-Andaman segments combined, and the Sumatra segment are 0.053, 0.11, and 0.21, respectively, which suggests that the slip in the northern segments involves a large amount of energy dissipation associated with water-filled thick sediments.
|Item Type:||Book Section|
|Additional Information:||© 2006 by the American Geophysical Union. I thank Chen Ji for providing me with the details of the finite source model for the Sumatra-Andaman earthquake. I thank Luis Rivera, Krishna Singh, and Greg Beroza for thoughtful comments for improvement. The seismograms used for this study were provided by the Global Seismic Network of the Incorporated Research Institutions for Seismology.|
|Official Citation:||Kanamori, H., 2006, The radiated energy of the 2004 Sumatra-Andaman earthquake: AGU Chapman Volume, Geophysical Monograph Series 170, "Earthquakes: Radiated Energy and the Physics of Faulting."|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||03 Jun 2011 18:15|
|Last Modified:||26 Dec 2012 13:17|
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