*Takeshi YOSHIDA¹, Takashi KUSUDA², Hisashi NIREI³ (1.Research Institute of Enviornmental Geology, Chiba, 2.Foremer Research Institute of Enviornmental Geology, Chiba, 3.Institute of medical geology)

*Hirokuni ODA¹ (1.National Institute of Advanced Industrial Science and Technology)

*Yusuke SUGANUMA¹, Makoto OKADA², Kenji HORIE¹, Hiroshi KAIDEN¹, Mami TAKEHARA³, Ryoko SENDA⁴, Jun-ichi KIMURA⁴, Osamu KAZAOKA⁵ (1.National Institute of Polar Research, 2.Ibaraki University, 3.Kyushu University, 4.JAMSTEC, 5.Research Institute of Environmental Geology, Chiba)

*Makoto OKADA¹, Yusuke SUGANUMA², Toru MARUOKA¹, Yuki HANEDA¹, Osamu KAZAOKA³ (1.Ibaraki University, 2.National Institute of Polar Research, 3.Research Institute of Environmental Geology, Chiba Pref.)

*Masayuki HYODO¹, Kenta TAKASAKI², Hayato MATSUSHITA², Ikuko KITABA¹, Shigehiro KATOH³, Akihisa KITAMURA⁴, Makoto OKADA⁵ (1.Research Center for Inland Seas, Kobe University, 2.Department of Earth and Planetary Sciences, Kobe University, 3.Division of Natural History, Hyogo Museum of Nature and Human Activities, 4.Institute of Geosciences, Faculty of Science, Shizuoka University, 5.Department of Earth Sciences, Faculty of Science, Ibaraki University)

*Takeshi HASEGAWA¹, Manami SUGAYA¹, Makoto OKADA¹, Nobutatsu MOCHIZUKI², Satomu FUJII², Hidetoshi SHIBUYA² (1.Faculty of Science, Ibaraki University, 2.Kumamoto University)

*Takehiko SUZUKI¹ (1.Tokyo Metropolitan University)