2022 Fiscal Year Final Research Report
Research on periodicity and risk assessment of debris flow occurrence in granite area
Project/Area Number |
19K23537
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Research Category |
Grant-in-Aid for Research Activity Start-up
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Allocation Type | Multi-year Fund |
Review Section |
0303:Civil engineering, social systems engineering, safety engineering, disaster prevention engineering, and related fields
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Research Institution | Fukuyama City University |
Principal Investigator |
Kato Nobuaki 福山市立大学, 都市経営学部, 准教授 (40845476)
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Project Period (FY) |
2019-08-30 – 2023-03-31
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Keywords | 土砂災害 / 土石流 / 周期性 / 免疫 / 降雨 / 崩壊 |
Outline of Final Research Achievements |
The purpose of this study is to clarify the effects of past disasters on the occurrence of landslide disasters. Targeting the southern part of Kure City, where debris flow disasters occurred four times in 1945, 1967, 1999, and 2018, the areas where collapses and debris flows occurred were identified by aerial photograph interpretation. We evaluated the effects of rainfall, man-made structures, and past collapses on these collapses. As a result, it was confirmed that the number of landslides that triggered the occurrence of debris flows was related to the number of rainfall indices (effective rainfall with different half-lives), which was the largest in the past. In addition, it was found that man-made structures and surrounding slopes of slopes that collapsed in the past are prone to collapse in subsequent rainfall events.
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Free Research Field |
砂防工学
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Academic Significance and Societal Importance of the Research Achievements |
土砂災害警戒情報は、降雨が過去に土砂災害が発生しなかった条件を上回る、あるいは、上回ることが予想されるときに発表される。この情報は、土砂災害の発生危険度のみを評価するものであり、発生が懸念される崩壊・土石流の数量や規模を予測するものではない。 本研究では、繰り返し土砂災害が発生する呉市南部地域において、過去最高となる降雨指標のパターン数と崩壊・土石流の数量・規模に関係があることを明らかにした。また、過去の崩壊や人工的な地形改変が以降の土砂移動に与える影響があることを明らかにした。 本成果を適用することにより、より適切かつ高度化した土砂災害発生予測が可能になることが期待される。
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