*Naoto HIRANO¹, Hideki IWANO², Kenji SHIMIZU³, Taisei MORISHITA⁴, Akihiro TAMURA⁵, Hirochika SUMINO⁶, Shuhei SAKATA⁷, Shiki MACHIDA⁸, Teruaki ISHII⁹, Tohru DANHARA², Shoji ARAI⁵, Takafumi HIRATA⁷ (1.Tohoku University, 2.Kyoto Fission-Track Co., Ltd., 3.JAMSTEC, 4.Japan Coast Guard, 5.Kanazawa University, 6.University of Tokyo, 7.Kyoto University, 8.Waseda University, 9.Fukada Geological Institute)

*Shiki MACHIDA¹, Tetsu KOGISO², Naoto HIRANO³ (1.Waseda University, 2.Kyoto University, 3.Tohoku University)

*Takaomi KAWANO¹, Naoto HIRANO², Taisei MORISHITA³ (1.Graduate School of Science and Faculty of Science, Tohoku University, 2.Center for Northeast Asian Studies, Tohoku University, 3.Hydrographic and Oceanographic Department, Japan Coast Guard)

*Arashi TAKI¹, Naoto HIRANO², Junji YAMAMOTO³, Shiki MACHIDA⁴, Teruaki ISHII⁵ (1.Graduate School of Science, Tohoku University, 2.Center for Northeast Asian Studies, Tohoku University, 3.Hokkaido University Museum, 4.Department of Resources and Environmental Engineering, Waseda University, 5.Fukada Geological Institute)

*Takaomi KAWANO¹, Naoto HIRANO², Taisei MORISHITA³ (1.Graduate School of Science and Faculty of Science, Tohoku University, 2.Center for Northeast Asian Studies, Tohoku University, 3.Hydrographic and Oceanographic Department, Japan Coast Guard)

*Arashi TAKI¹, Naoto HIRANO², Junji YAMAMOTO³, Shiki MACHIDA⁴, Teruaki ISHII⁵ (1.Graduate School of Science, Tohoku University, 2.Center for Northeast Asian Studies, Tohoku University, 3.Hokkaido University Museum, 4.Department of Resources and Environmental Engineering, Waseda University, 5.Fukada Geological Institute)