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Earth Planets Space, Vol. 58 (No. 2), pp. 203-209, 2006

Rupture process of the 2004 great Sumatra-Andaman earthquake estimated from tsunami waveforms

Yuichiro Tanioka1, Yudhicara2,6, Tomohiro Kususose1, S. Kathiroli3, Yuichi Nishimura1, Sin-Iti Iwasaki4, and Kenji Satake5

1Institute of Seismology and Volcanology, Hokkaido University, N10W8 Kita-ku, Sapporo 060-0810, Japan
2Department of Geophysics and Meteorology, Bandung Institute of Technology, Jalan Ganeca 10, Bandung 40132, Indonesia
3National Institute of Ocean Technology, NIOT Campus, Velachery-Tambaram Main road, Pallikaranai, Chennai, 601302, India
4National Research Institute for Earth Science and Disaster Prevention, 3-1 Tennodai, Tsukuba 305-0006, Japan
5Active Fault Research Center, National Institute of Advanced Industrial Science and Technology, Site C7 1-1-1 Higashi, Tsukuba 305-8567, Japan
6Marine Geological Institute, Jl. Dr. Junjunan No. 236 Bandung 40174, Indonesia

(Received July 28, 2005; Revised December 5, 2005; Accepted December 13, 2005; Online published February 17, 2006)

Abstract: Rupture process of the 2004 Sumatra-Andaman earthquake is estimated using tsunami waveforms observed at tide gauges and the coseismic vertical deformation observed along the coast. The average rupture speed of the 2004 Sumatra-Andaman earthquake is estimated to be 1.7 km/s from tsunami waveform analysis. The rupture extends about 1200 km toward north-northwest along the Andaman trough. The largest slip of 23 m is estimated on the plate interface off the northwest coast in the Aceh province in Sumatra. Another large slip of 21 m is also estimated on the plate interface beneath the north of Simeulue Island in Indonesia. The other large slip of 10-15 m is estimated on the plate interface near Little Andaman and Car Nicobar Inlands. The total seismic moment is calculated to be 7.2 × 1022 Nm (Mw 9.2) which is similar to the other studies using seismic waves (Park et al., 2005; Ammon et al., 2005).
Key words: 2004 Sumatra-Andaman tsunami, numerical simulation, tsunami waveform inversion, slip distribu-tion.


Corresponding author E-mail: tanioka@eos.hokudai.ac.jp


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