Earth Planets Space, Vol. 63 (No. 7), pp. 565-569, 2011
Yasuhiro Yoshida1, Hiroshi Ueno2, Daisuke Muto2, and Shigeki Aoki1
1Seismology and Volcanology Research Department, Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
2Seismological and Volcanological Department, Japan Meteorological Agency, 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan
(Received April 13, 2011; Revised May 12, 2011; Accepted May 13, 2011; Online published September 27, 2011)
We have derived preliminary results for the source process of the March 11, 2011 off the Pacific coast of Tohoku Earthquake (the 2011 Tohoku Earthquake; Mw = 9.0) from two types of seismic waveform data: teleseismic P waves and regional strong motion data. The common features of these two analyses are as follows: (a) The main rupture is located to the east of the initial break point (the shallower side of the hypocenter), and maximum slip amounts were more than 25 m. (b) The size of the main fault was about 450 km in length and 200 km in width; the duration of rupture was more than 150 s; and Mw was 9.0. (c) The initial rupture gradually expanded near the hypocenter (0-40 s) and subsequently propagated both southwards and northwards.
Key words: Source process, teleseismic wave, strong motion, the 2011 off the Pacific coast of Tohoku Earthquake.