2022 Fiscal Year Final Research Report
Processes of river incision in small and large scales: experimental study for understanding of geomorphological dynamics
| Project/Area Number |
19K01157
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Multi-year Fund |
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| Section | 一般 |
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| Review Section |
Basic Section 04010:Geography-related
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| Research Institution | Kanazawa University |
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Principal Investigator |
Endo Noritaka 金沢大学, 地球社会基盤学系, 准教授 (60314358)
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| Co-Investigator(Kenkyū-buntansha) |
谷口 圭輔 筑波大学, アイソトープ環境動態研究センター, 研究員 (80774794)
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| Project Period (FY) |
2019-04-01 – 2023-03-31
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| Keywords | 岩盤河川 / 山岳河川地形 |
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| Outline of Final Research Achievements |
The obtained data from one-dimensional flume experiment showed that the possibility of occurrence of plucking depends on both longitudinal and vertical sizes of the protrude rock block. Three-dimensional basin-scale model experiments were conducted to investigate the relationship between the type of tilting uplift and the migration of drainage divide. In application for a natural landform, we examined the mobility of drainage divides in Sado Island, and found that the divides are inactive in many places despite of being on the slower uplift side of the island, which can be attributed to the land expansion at the coast on the faster uplift side.
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| Free Research Field |
地形学
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| Academic Significance and Societal Importance of the Research Achievements |
隆起速度が速い（地殻変動が活発な）地域地域は、遅い地域と比べて斜面崩壊や土砂災害の発生頻度が高いが、これは河川の下刻に伴う斜面不安定化と関係がある。個々の斜面崩壊はほぼ一瞬であり、一か所につき劇的地形変化の発生は低頻度である。一方、流域全体では異なる箇所で多数生じるとともに、流路ネットワークを通じて相互作用が起き、河川地形は隆起に対し非線形に応答する。タイムスケールが大きく異なる現象の関係を理解して、短期的かつ長期的な地形変化に伴う社会的リスク評価を実現するには定量的な理解が不可欠だが、実用的なモデルは確立していない。本研究の成果は、そうした定量的モデルの基礎となる素過程の理解を前進させた。
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