| Project/Area Number |
16380106
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
林学・森林工学
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| Research Institution | Kagoshima University |
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Principal Investigator |
JITOUSONO Takashi Kagoshima University, Faculty of Agriculture, Associate professor, 農学部, 助教授 (50145455)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMOKAWA Etsuro Kagoshima University, Faculty of Agriculture, Professor, 農学部, 教授 (60041670)
TERAMOTO Yukiyoshi Kagoshima University, faculty of agriculture, Research Associate, 農学部, 助手 (10301392)
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| Project Period (FY) |
2004 – 2006
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| Project Status |
Completed (Fiscal Year 2006)
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| Budget Amount *help |
¥7,800,000 (Direct Cost: ¥7,800,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥1,400,000 (Direct Cost: ¥1,400,000)
Fiscal Year 2004: ¥5,100,000 (Direct Cost: ¥5,100,000)
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| Keywords | southern Kyushu / Volcanic area / Landslide of talus slope / Prediction of potential landslide / Hydrological observation / Water quality / Hydrogeomorphology / Groundwater |
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| Research Abstract |
In southern Kyushu, two types of landslide which have rarely taken place were caused by a rise in the groundwater level. The one is sliding of talus slope at the valley head scarred on Shirasu plateau, and the other one is a deep-seated landslide in the area of the volcanic rocks. In this study, the mechanism of these landslides and the possibility of predicting the potential landslide sites are examined based on field study.
1. The landslides of talus slope at the valley head occur in the Shirasu valleys with a certain drainage area of groundwater. The low water discharge in the valley is proportional to the drainage area of groundwater. Therefore, the low water discharge serves as an effective index to predict high potential sites for landslide of talus slope. The groundwater level in the talus slope responds to storms in a few hours. This rapid flow of groundwater is mainly attributed to the pipe flow. On the other hand, there is also a late flow of groundwater which responds to storms after several months or more. This late flow is mainly attributed to the matrix flow. If the late flow and the rapid flow of groundwater overlap, the groundwater level in the talus slope will become very high and the potential for the landslide will increase.
2. A deep-seated landslide occurred in Izumi City, 1997. This landslide was caused by rising of groundwater level associated with heavy rainfall, the hydrogeomorphological formation of the underground area prone to storage of groundwater, and deeply weathered volcanic rocks. It was ascertained that effective indicators for predicting potential site of landslide were the distributions of gentle slopes, boundaries between aquifer and aquiclude, the change points of stream discharge, electric conductivity, and silica concentrations along a longitudinal stream, and the distribution of springs.
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