[1] Osaka Univ, Grad Sch Sci, Dept Earth & Space Sci, Toyonaka, Osaka 560, Japan
[2] Kochi Univ, Ctr Adv Marine Core Res, Nankoku, Kochi, Japan
[3] Japan Agcy Marine Earth Sci & Technol, Kochi Inst Core Sample Res, Nankoku, Kochi, Japan
[4] Marine Works Japan Ltd, Nankoku, Kochi, Japan
[5] Yamaguchi Univ, Grad Sch Sci & Engn, Dept Earth Sci, Yamaguchi, Japan
[6] Tohoku Univ, Grad Sch Sci, Dept Geoenvironm Sci, Sendai, Miyagi 980, Japan
[7] Japan Agcy Marine Earth Sci & Technol, Ctr Deep Earth Explorat, Yokohama, Kanagawa, Japan
[8] Tokyo Gakugei Univ, Fac Educ, Koganei, Tokyo 184, Japan
[9] Kochi Univ, Dept Nat Environm Sci, Kochi 780, Japan
[10] Japan Agcy Marine Earth Sci & Technol, Inst Res Earth Evolut, Yokosuka, Kanagawa 2370061, Japan
[11] Natl Inst Adv Ind Sci & Technol, Inst Georesources & Environm, Tsukuba, Ibaraki, Japan
[12] Natl Inst Adv Ind Sci & Technol, Inst Geol & Geoinformat, Tsukuba, Ibaraki, Japan
[13] Natl Res Inst Earth Sci & Disaster Prevent, Earthquake Res Dept, Tsukuba, Ibaraki, Japan
[14] Stanford Univ, Sch Earth Sci, Dept Geophys, Stanford, CA 94305 USA
[15] Natl Taiwan Univ, Dept Geosci, Taipei 10764, Taiwan