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Volume 47 (2006 - 200･･･
- Issue 6 Pages 323-
- Issue 5 Pages 252-
- Issue 4 Pages 188-
- Issue 3 Pages 120-
- Issue 2 Pages 68-
- Issue 1 Pages 2-
Volume 47, Issue 3
Displaying 1-5 of 5 articles from this issue
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Shuji AJIMA, Norifumi TODAKA, Teruki IWATSUKI, Ryoji FURUE2006 Volume 47 Issue 3 Pages 120-130
Published: August 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe methodology development for evaluating hydrogeochemical disturbance caused by the construction of underground facilities is one of the important tasks in the program of the Mizunami Underground Research Laboratory (MIU).
This paper describes hydrogeochemical modeling around the MIU using M3 (Multivariate Mixing and Mass balance) analysis. According to the modeling, groundwater is characterized by the mixing process among four types of reference water, groundwaters in deep granite, shallow granite and shallow sedimentary rocks, and surface water, including waterrock interaction and cation exchange process. It is also showed that groundwater around MIU is mainly described quantitatively using reference water mixing ratio. It is suggested that the monitoring of mixing ratios of each reference water in groundwater will be delineated by M3 analysis based on the hydrogeochemical change during construction and operation of MIU. The M3 analysis is a useful approach for groundwater monitoring and analysis.View full abstractDownload PDF (3594K) -
Wataru TANIKAWA, Toshihiko SHIMAMOTO2006 Volume 47 Issue 3 Pages 131-139
Published: August 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSKnowing the difference between gas and water permeabilities is significant not only for solving gas-water two-phase flow problems, but also for quick measurements of permeability using gas as pore fluid. We have thus measured intrinsic permeability of porous sedimentary rocks from Western Foothills of Taiwan, using nitrogen gas and water as pore fluids, during several effective-pressure cycling tests at room temperature. The observed difference in gas and water permeabilities have been analyzed in view of the Klinkenberg effect. This effect is primarily due to slip flow of gas at pore walls which enhances gas flow when pore sizes are very small. Experimental results show (1) that gas permeability is larger than water permeability by several times to one order of magnitude, (2) that gas permeability increases with increasing pore pressure, and (3) that water permeability slightly increases with increasing pore-pressure gradient across the specimen. The results (1) and (2) can be explained by the Klinkenberg effect quantitatively with an empirical power law for the Klinkenberg constant. Thus water permeability can be estimated from gas permeability. The Klinkenberg effect is important when permeability is lower than 10-18 mm2 and at low differential pore pressures, and its correction is essential for estimating water permeability from the measurement of gas permeability. A simple Bingham-flow model of pore water with a fixed pore size can explain the overall trend of the result (3) above. More sophisticated models with a pore-size distribution and with realistic rheology of water film is needed to account for the observed deviation from Darcy's law, i. e., the dependence of water permeability on the pore-pressure gradient.View full abstractDownload PDF (1822K) -
Ryuta HATAYA, Makoto YANAGIDA, Shinya YAMAMOTO, Masaru SATO, Akira FUR ...2006 Volume 47 Issue 3 Pages 140-151
Published: August 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSWe are studying on tectonic movement during late Quaternary around the epicenter of the Mid Niigata prefecture Earthquake in 2004. In this paper, we report stratigraphy of fluvial terraces in the north Uonuma Hill near the epicenter of this earthquake, and preliminarily discuss the activity of the Muikamachi fault. This fault is located at the eastern edge of the Uonuma hill, and some researchers think that it caused the earthquake in 2004. We divided fluvial terraces into three terrace groups by the air-photo interpretation: higher group, middle group and lower group. The higher group includes Hf1, Hf2 and Hf3 terraces, and the lower group includes Lf1, Lf2, Lf3 and Lf4 terraces. The Hf3 terrace was formed, at least, before MIS6 (MIS: marine oxygen isotope stage), and is assumed to be formed during MIS8. It is probable that the Mf terrace was formed in MIS6. The formation ages of Lf1, Lf2, Lf3 and Lf4 are estimated to MIS5/MIS4-MIS4/MIS3, MIS3/MIS2, MIS2 and MIS1 each other. Using the uplift index of the values of relative height between terraces, we estimated that the uplift difference on the both side of the Muikamachi fault during late Quaternary was more than 40m. It suggests that the slip rate of the Muikamachi fault is more than 0.4m/103 year.View full abstractDownload PDF (2662K) -
Takaaki WAJIMA, Masahiko BESSHO, Takashi NISHIYAMA2006 Volume 47 Issue 3 Pages 152-155
Published: August 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSAt Sumikawa geothermal plant in Akita prefecture, the geothermal water after separator is directed back underground through a re-injection well because it contains high level of As (ca. 13mg/l). In order to establish the effective system for the removal of As from geothermal water using H2S gas included in exhausted gas, we examined the basic reaction of As removal from geothermal water by artificial H2S gas. In the case of less than pH 4 of geothermal water, As concentration of the water dropped to below 0.1mg/l after passing through H2S gas. This process can be combined with removal method of supersaturated silica by using Al ion.View full abstractDownload PDF (1081K) -
Shuichiro YOKOTA2006 Volume 47 Issue 3 Pages 156-161
Published: August 10, 2006
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSLong history of the earth includes enormous information regarding the change of the nature, and countless hints for human being in order to coexist with natural environment over the future. Although the information on past natural phenomena is available for predicting future changes of the nature, some transformation of the information is necessary for obtaining natural environments by analyzing it.
Natural phenomena should be changed in terms of time and space into proper ones in the sense of mankind. The degree and its changes of natural environments for individual persons with their activity space must be estimated on the basis of mixed influences of natural phenomena. The field of engineering geology, which can consider the nature from the view point of mankind society, may play important role for such transformation. It becomes possible to discuss the influence of mankind activity on the nature of the earth, when these view points were established.View full abstractDownload PDF (1065K)
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