| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1987: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1986: ¥1,300,000 (Direct Cost: ¥1,300,000)
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| Research Abstract |
It can be observe the constant surface runoff water in Mihara Volcano, Hachijo Island, uncommonly in Izu Islands. In this investigation, the groundwater spouting mechanism has been studied by geological survay,and groundwater balance model was estimated. Results of this work are as follow.
1. Mihara Volcano consists of Pleistocene volcanic rocks such as Pre-Mihara Volcanic Rocks, Lower mihara-yama Formation, Middle Mihara-yama Formation and Upper Mihara-yama Formation in ascending order.
2. Because the surface consists of pyroclastic material, almost of precipitation on the slope of Mihara Volcano seeps down into the aquiferes.
3. Geological structure of volcano is not symmetric, Upper Mihara Formation distributes thick on west side of volcano.So that, there are no surface water in this area.
4. The aquifers of this area consist of lavas and pyroclastic materials in Upper Mihaea-yama Formation and Middle Mihara-yama Formation.
5. The groundwater recharge volume has been caluculated as total precipitation - (total evaporate x evapotranspiration rate).
6. It was caluculated that the total volume of runoff from groundwater,and these groundwater runoff rate of this area are different earch other depended on the geological structure.
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