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Earth Planets Space, Vol. 56 (No. 12), pp. 1271-1277, 2004

Moho and Philippine Sea plate structure beneath central Honshu Island, Japan, from teleseismic receiver functions

Kazuo Yoshimoto1, Hiroatsu Fujisawa2, Tomomi Okada2, Norihito Umino2, Akira Hasegawa2, Kazushige Obara3, Katsuhiko Shiomi3, Hiroaki Tsukahara4, Shigeru Okamoto5, Taku Kawanaka5, Hiroshi Sato6, Takeshi Nishimura2, Haruo Sato2, and Masakazu Ohtake2

1Graduate School of Integrated Science, Yokohama City University, 22-2 Seto, Kanazawa, Yokohama 236-0027, Japan
2Graduate School of Science, Tohoku University, Aramaki, Aoba, Sendai, Miyagi 980-8578, Japan
3National Research Institute for Earth Science and Disaster Prevention, 3-1 Tennodai, Tsukuba, Ibaraki 305-0006, Japan
4Faculty of Science, Shinshu University, 3-1-1 Asahi, Matsumoto, Nagano 390-8621, Japan
5JGI inc., 1-5-21 Otsuka, Bunkyo, Tokyo 112-0012, Japan
6Earthquake Research Institute, University of Tokyo,1-1-1 Yayoi, Bunkyo, Tokyo 113-0032, Japan

(Received May 30, 2004; Revised September 3, 2004; Accepted September 27, 2004)

Abstract: We used teleseismic P waves recorded by the J-array, the Hi-net and a temporal local seismic network to investigate the three-dimensional topography of the Moho and the Philippine Sea plate beneath central Honshu Island, Japan. An image of the subsurface discontinuities beneath the region, derived from receiver function analysis, depicts the Philippine Sea plate dipping toward the north with complex local curvatures. The Moho is clearly detected in the northern part of the area studied, and its depth increases to the center of the island. Receiver functions from the stations adjacent to the Itoigawa-Shizuoka tectonic line indicate the step-like topography of the Moho directly beneath this tectonic line.
Key words: Moho, Philippine Sea plate, Itoigawa-Shizuoka tectonic line, median tectonic line, receiver function.


Corresponding author E-mail: k_yoshi@yokohama-cu.ac.jp


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