2018 Fiscal Year Final Research Report
Improving prediction models for shallow landslides based on channel-head mapping using LiDAR DEMs
| Project/Area Number |
16K01214
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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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| Research Field |
Geography
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| Research Institution | University of Tsukuba |
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Principal Investigator |
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| Co-Investigator(Kenkyū-buntansha) |
土志田 正二 総務省消防庁消防大学校(消防研究センター), 技術研究部地震等災害研究室, 主任研究官 (20526909)
田中 靖 駒澤大学, 文学部, 教授 (80348888)
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| Research Collaborator |
FURUICHI Takahisa
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| Project Period (FY) |
2016-04-01 – 2019-03-31
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| Keywords | 地形学 / 微地形 / 土砂災害 / 花崗岩 / 斜面崩壊 |
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| Outline of Final Research Achievements |
Timing of the past-landslide events is essential for detecting slopes with higher potential for landsliding. This study proposes that location of channel heads will be an useful index for estimating timing of the past landslide events. We have examined landslide risk mapping, dates of colluvial deposits, channel-head migration in two granitic mountains (Hofu and Hiroshima-Asaminami) where debris-flow disaster occurred in recent years.
In Hiroshima-Asaminami site, channel heads with large source areas have higher potential of landsliding. In addition, such deposits around channel heads have relatively older radiocarbon dates. These valley heads have been buried in longer distance (more than 50 m) along the old channel since the last landslide event. In contrast, similar relationship has not clearly been shown in Hofu site, although the number of dating samples is not enough. Further data will be required for application of the method for prediction of landslide locations.
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| Free Research Field |
地形学
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| Academic Significance and Societal Importance of the Research Achievements |
斜面崩壊位置の予測は土砂災害を予測するうえで非常に重要である．2018年西日本豪雨で多発した表層崩壊の場合，時間がたつにつれて崩壊リスクが高くなるという現象（免疫性）が知られている．現在の崩壊予測では，過去の崩壊履歴を考慮に入れていないため，それらを考慮した予測手法の確立が必要である．本研究では，最近取得できるようになった高解像度の地図を利用し，微地形の分析を崩壊の予測に生かそうという試みである．研究の結果，予測手法が適用可能と思われるケースとそうでないケースの両方が確認された．今後，具体的な展開に向けてさらに検討が必要であることが明らかになった．
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