2022 Fiscal Year Final Research Report
Submarine slope failure due to shallow-type methane hydrate dissociation: a case of a submarine slide in the offshore of San'in region
Project/Area Number |
19K03994
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Research Category |
Grant-in-Aid for Scientific Research (C)
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Allocation Type | Multi-year Fund |
Section | 一般 |
Review Section |
Basic Section 17030:Human geosciences-related
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Research Institution | Kochi University (2021-2022) Tottori University (2019-2020) |
Principal Investigator |
ISHIDA Naoto 高知大学, 海洋コア総合研究センター, 客員講師 (20534746)
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Project Period (FY) |
2019-04-01 – 2023-03-31
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Keywords | 表層型メタンハイドレート / 海底地すべり / ガスハイドレート安定領域 / 日本海 |
Outline of Final Research Achievements |
A submarine slide in the offshore of San'in region was investigated from the viewpoint of dissociation of shallow-type methane hydrate. The age of the submarine slide located in the southwestern slope of the Oki Trough, off Tottori, was estimated to be 44 ka. Based on the measured water temperature, salinity, geothermal gradient, heat flow, sedimentation rate, etc., the base of the gas hydrate stability was thought to be located just below the landslide mass at the time. After the MIS5e interglacial, methane hydrate dissociation had progressed along the base of the stability in response to a sea-level fall. The results of this study strongly support a scenario that methane hydrate dissociation induced submarine slope failures.
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Free Research Field |
メタンハイドレート
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Academic Significance and Societal Importance of the Research Achievements |
本研究では,山陰沖日本海の海底地すべりについて発生機構を検討した.その結果,発生時期が海水準低下期であることが明らかになり,水圧の減少がメタンハイドレートの分解を進行させ,やがて斜面が滑動した可能性が高いという結論を得た.近年資源として注目される日本海の表層型メタンハイドレートは,その安定性を左右する外的要因の変化の影響を受けやすい特性がある.この成果は,メタンハイドレートの分解が海底地すべりを誘発する可能性を具体例をもって示し,新たな視点を与えるものとして重要である.
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