| Project/Area Number |
14540390
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
固体地球物理学
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| Research Institution | The University of Tokyo |
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Principal Investigator |
UYESHIMA Makoto The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (70242154)
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| Co-Investigator(Kenkyū-buntansha) |
OGAWA Tsutomu The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助手 (00345175)
NAKAI Shunichi The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (50188869)
YOSHIDA Shingo The University of Tokyo, Earthquake Research Institute, Associate Professor, 地震研究所, 助教授 (20202400)
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| Project Period (FY) |
2002 – 2003
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| Project Status |
Completed (Fiscal Year 2003)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2003: ¥1,500,000 (Direct Cost: ¥1,500,000)
Fiscal Year 2002: ¥1,400,000 (Direct Cost: ¥1,400,000)
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| Keywords | streaming potential coefficient / room experiment / self potential / Miyakejima island |
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| Research Abstract |
We determined zeta-potential in various physical and chemical conditions by room experiment to quantitatively evaluate interstitial fluid's flow from temporal and spatial self-potential variations in association with Miyakejima 2000 summit eruption. In the first year, we designed and prepared necessary apparatus and collected rock samples on Miyakejima and Kozushima islands. Since we found that the topographic effect on Kozushima island is about 10mV/m (10mV decrease pre 1m altitude change), which is 10 times larger than that on Miyakejima island (1mV/m), measurement and comparison of zeta-potentials for the rock samples in both islands become another target of this study. Mikyakejima and Kozushima islands are composed of basalts and rhyolites, respectively.
Main results are as follows:
(1)p dependence of zeta-potential for Miyakejima rocks was determined by using interstitial fluids of HCl-KCl-KOH composition. Zeta-potential values in pH 3-10 range from -10 to -20 mV, whose absolute value is 10 times smaller than Ishido & Mizutani (1981)'s results, which were regarded as representative zeta-potential values. In the higher pH conditions, zeta-potential absolute value gets larger and becomes similar to their results.
(2)For both islands' rocks, pH dependence of zeta-potential in pH>3 range is almost the same. In the smaller pH range, zeta-potential absolute value of Miyakejima rocks is getting smaler, becomes zero at about pH 2 and changed to be positive in further acid condition, whereas that of Kozushima rocks shows no such significant variation and remains negative.
(3)For results with the finer rock samples, the larger zeta-potential absolute value is obtained.
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