Japan Geoscience Union Meeting 2018

Presentation information

[JJ] Oral

M (Multidisciplinary and Interdisciplinary) » M-IS Intersection

[M-IS17] Gas hydrates in environmental-resource sciences

Tue. May 22, 2018 3:30 PM - 5:00 PM A11 (Tokyo Bay Makuhari Hall)

convener:Hitoshi Tomaru(Department of Earth Sciences, Chiba University), Akihiro Hachikubo(Kitami Institute of Technology), Atsushi Tani(神戸大学 大学院人間発達環境学研究科, 共同), Shusaku Goto(Institute for Geo-Resources and Environment National Institute of Advanced Industrial Science and Technology), Chairperson:Ishida Naoto, Aoki Shinsuke

3:30 PM - 3:45 PM

[MIS17-06] Response of BGHS to sea-level change in shallow gas hydrate field

*Naoto Ishida1, Hitoshi Tomaru2, Takao Ebinuma1, Ryo Matsumoto3 (1.Social Systems and Civil Engineering, Graduate School of Engineering, Tottori University, 2.Chiba University, 3.Meiji University)

Keywords:shallow gas hydrate, BGHS, sea-level change, Oki Trough

This study focuses on BGHS change in the Oki Trough, one of the shallow-gas hydrate fields in the eastern margin of Japan Sea, and evaluates influences of sea-level on accumulation and disassociation of gas hydrate. At the observation site in the southwestern slope of Oki Trough (OT-2A: 763 m in water depth), present BGHS depth is estimated to be 151 mbsf. The BGHS was 24 m shallower than present during the Last Glacial Maximum (20 Ka) in response to a 120 m sea-level fall. Submarine ground around OT-2A was subdivided into six domains based on the history of gas hydrate state after the last interglacial (125 Ka). A great many submarine slides have been reported in the southwestern Oki Trough. It is highly probable that gas hydrate disassociation makes the submarine ground unstable. Relation between slope failure and gas hydrate disassociation is necessary to examine.
This study was partly conducted under the commission from AIST as a part of the methane hydrate research project funded by the Ministry of Economy, Trade and Industry, Japan.