TERRAPUB Earth, Planets and Space

Earth Planets Space, Vol. 58 (No. 12), pp. 1573-1576, 2006


Undersea co-seismic crustal movements associated with the 2005 Off Miyagi Prefecture Earthquake detected by GPS/acoustic seafloor geodetic observation

Yoshihiro Matsumoto1, Masayuki Fujita1, Tadashi Ishikawa1, Masashi Mochizuki2, Tetsuichiro Yabuki1, and Akira Asada2

1Hydrographic and Oceanographic Department, Japan Coast Guard, 5-3-1 Tsukiji, Chuo-ku, Tokyo 104-0045, Japan
2Institute of Industrial Science, the University of Tokyo, 4-6-1 Komaba, Meguro-ku, Tokyo 153-8505, Japan

(Received December 5, 2005; Revised January 26, 2006; Accepted April 26, 2006; Online published February 2, 2007)

Abstract: We have been carrying out seafloor geodetic observations at two reference points situated off Miyagi Prefecture, northeastern Japan, using the GPS/Acoustic combination technique. Comparison of position estimates before and after the 2005 Off-Miyagi Prefecture Earthquake revealed a co-seismic crustal movement as large as 10 cm eastward at the site approximately 10 km from the epicenter, while no prominent movement was found at another site located 60 km away from the epicenter. The results at these two sites are consistent with crustal deformation calculated from the rectangular dislocation model on the fault derived from crustal movements observed at GEONET stations on land.
Key words: GPS/acoustic, seafloor geodetic observation, co-seismic crustal movement, the 2005 Off Miyagi Prefecture Earthquake.

Corresponding author E-mail: yoshihiro-matsumoto@kaiho.mlit.go.jp

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