2023 Fiscal Year Final Research Report
Quantitative understanding of time-series sedimentation and erosion processes by tsunamis.
| Project/Area Number |
18KK0378
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| Research Category |
Fund for the Promotion of Joint International Research (Fostering Joint International Research (A))
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| Allocation Type | Multi-year Fund |
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| Research Field |
Geology
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| Research Institution | Ibaraki University |
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Principal Investigator |
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| Project Period (FY) |
2019 – 2023
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| Keywords | 津波堆積物 / 堆積過程 / 水路実験 |
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| Outline of Final Research Achievements |
To develop a qualitative understanding of the sedimentary erosion process by unsteady tsunami currents and to elucidate and quantitatively understand the mechanisms of the phenomenon, a project was carried out in collaboration with researchers at the University of Hull, UK, who are familiar with the physical mechanisms of sedimentation processes and the effects of muddy sediments in the bottom material. In particular, hydrographic experiments and analyses were conducted to validate a sediment transport model that takes into account the unsteadiness of the flow and to clarify the influence of the muddy sediment component on sediment transport under unsteady flow. As a result, we were able to quantitatively evaluate the extent of the influence of unsteady flow and the influence in the case of sand and mud mixtures.
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| Free Research Field |
地質学
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| Academic Significance and Societal Importance of the Research Achievements |
本研究によって，これまで津波による堆積侵食シミュレーションなどに用いられてきた準定常流に基づいたモデルの妥当性が定量的に確認された．一方で，津波堆積物の堆積構造形成過程における非定常性の影響の可能性は残されており，今後その検討の重要性が見出された．また津波に限らず非定常流下における砂泥混合物輸送の複雑性が明らかになった．特に泥の特徴や割合の影響の大きさが定量的に示され，流れによる底質の巻き上げのシミュレーションなどにおいて無視できないことが明らかになった．
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