2023 Fiscal Year Final Research Report
Development of a Machine Learning Method for Extracting Debris Flow Hazard Basins Focused on Debris Flow Fans
| Project/Area Number |
21K05674
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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 40010:Forest science-related
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| Research Institution | Hokkaido Research Organization |
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Principal Investigator |
Koshimizu Ken'ichi 地方独立行政法人北海道立総合研究機構, 産業技術環境研究本部 エネルギー・環境・地質研究所, 研究主任 (30636171)
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| Co-Investigator(Kenkyū-buntansha) |
石丸 聡 地方独立行政法人北海道立総合研究機構, 産業技術環境研究本部 エネルギー・環境・地質研究所, 部長 (50446366)
今泉 文寿 静岡大学, 農学部, 教授 (80378918)
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| Project Period (FY) |
2021-04-01 – 2024-03-31
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| Keywords | 沖積錐 / 土石流 / 機械学習 / GIS / 地形・地質 |
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| Outline of Final Research Achievements |
We investigated the morphological conditions of a drainage basins that contribute to the formation of debris flow fans using decision tree analysis and field surveys. The analysis was conducted at two sites with distinct rock strengths: Neogene sedimentary rock and Paleogene accretionary complex sites. Many debris flow fans are distributed in these sites. Decision tree analysis was used with the presence or absence of debris flow fans as the objective variable and the morphological variables of the drainage basin as explanatory variables. The first and second important morphological factors affecting the presence or absence of debris flow fans in both sites were relief ratio and most frequent slope gradient, respectively. However, the threshold of morphological parameters needed to form debris flow fans differed depending on the geological features. We also confirmed the history of debris flow occurrences in basins where debris flow fans were estimated by decision tree analysis.
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| Free Research Field |
砂防学
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| Academic Significance and Societal Importance of the Research Achievements |
土石流危険流域の指定に際し、従来は様々な地質分布域の流域において、客観的かつ的確な判別基準を定めるための科学的手法の確立が不足していた。機械学習を用いた本手法は、沖積錐形成に寄与する流域の地形条件を定量的に把握でき、様々な地質分布域の土石流発生ポテンシャルの評価が可能になる。加えて、河川の浸食や人工改変により実際には沖積錐が発達しない流域においても、潜在的な土石流発生のポテンシャルを把握することに活用できる。
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