*Takashi Miyazaki¹, J B Gill², C Hamelin³, S M DeBari⁴, Tomoki Sato¹, Yoshihiko Tamura¹, Jun-Ichi Kimura¹, Bogdan Stefanov Vaglarov¹, Qing Chang¹, Ryoko Senda⁵, Satoru Haraguchi⁶ (1.Research Institute for Marine Geodynamics, Japan Agency for Marine-Earth Science and Technology, 2.University of California, Santa Cruz, 3.University of Bergen, 4.Western Washington University, 5.Kyushu University, 6.University of Tokyo)