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Sasao, Eiji
no journal, ,
no abstracts in English
Umeda, Koji; Ninomiya, Atsushi
no journal, ,
We suggest the possibility that the helium isotope can be regarded as a tool for investigating concealed active faults with no surface expression, even as water samples collected from shallow wells.
Yamada, Kunimi; Hanamuro, Takahiro; Tagami, Takahiro*; Shimada, Koji; Takagi, Hideo*; Iwano, Hideki*; Danhara, Toru*; Umeda, Koji
no journal, ,
no abstracts in English
Iwatsuki, Teruki; Ishii, Eiichi
no journal, ,
It is required to demonstrate the long-term variation of hydrochemical condition for the geological isolation of high level radioactive waste. This study illustrates the relationship among the past geological processes and hydrochemical condition, and estimate the long-tern variation of groundwater chemistry at deep part of Horonobe area, Japan.
Morikawa, Keita*; Iwatsuki, Teruki; Hosoya, Shinichi*
no journal, ,
Measurement of redox potential in deep groundwater was conducted at ground surface and in-situ monitoring part of borehole to refine the properties of ORP electrode. The results show that the time to reach the stable value of redox potential depends on shape of Pt electrode.
Niizato, Tadafumi; Igarashi, Yaeko*; Yasue, Kenichi
no journal, ,
Based on a geomorphological and geological investigation, we can clarify the surface environments during late Last Glacial period in the Horonobe area, northern Hokkado.
Hanamuro, Takahiro; Umeda, Koji; Maeda, Katsuhiko*
no journal, ,
no abstracts in English
Ninomiya, Atsushi; Umeda, Koji
no journal, ,
We compiled existing helium isotope data to inspect an implication of geographic distribution of 
He/
He ratios derived from hot spring gases to the geophysical structure of the Niigata-Kobe Tectonic Zone (NKTZ) which is a high-strain-rate zone extending from Niigata to Kobe. The result reinforces the clear relationship between helium isotope variations on the surface and the seismicity and resistivity structure of the crust and upper mantle along the NKTZ. In addition, the helium isotopes in hot spring gases may be recognized as a useful geochemical indicator of the presence of concealed active faults with compressional tectonics.
Hagiwara, Hiroki; Mizuno, Takashi
no journal, ,
This report describes the results of investigations on geochemical characteristic of groundwater in the 07MI07 borehole. In this investigation, it was cleared that chemical components of groundwater, such as sodium, chlorine show the feature that the concentration decreases with far from shaft. It was affected by shaft drilling.
Maekawa, Keisuke; Tomura, Goji; Yokota, Hideharu
no journal, ,
no abstracts in English
Sakai, Ryutaro; Munakata, Masahiro; Kimura, Hideo
no journal, ,
It is important to evaluate effects on the groundwater flow system by the natural phenomena in the safety assessment of geological disposal of radioactive waste. In this report, we study change effecting on the groundwater flow system by literature reviews. This study suggests that the non-current paleo-fresh water at present is possible to move to discharged area at sea floor in the next glacial period by denudation of marine-clay sediments and to become stagnant water again in the next interglacial period by deposition of marine-clay sediments in coastal region. Therefore it is important to predict the scenario considering the denudation and deposition correlated with transgression and regression that could affect the change of groundwater flow velocity, groundwater flow path and groundwater chemical characteristics during the glacial and interglacial period.
Ichihashi, Masaki
no journal, ,
JAEA conducts the observation of radionuclides in the atmosphere as the monitoring activities of CTBT. This study analyzed the correlation between earthquake-days and the Be-7 concentration observed at Takasaki for the period from late August, 2003 to early December, 2007. "Earthquake-day" is defined as a day when one or more earthquakes of M 
5 occur. Aftershocks are not included. It is found that the average of the Be-7 concentration is significantly greater on earthquake-days with a focal depth 40 km than that on the other days. This may suggest that there exists a possible physical relationship between earthquakes and Be-7 concentration in the atmosphere.
Asano, Takahiro; Sasaki, Yoshito; Kageyama, Koji*; Yoshikawa, Hideki
no journal, ,
no abstracts in English
Matsunaga, Takeshi; Tsuzuki, Katsunori
no journal, ,
Dissolved organic materials (DOM) in river water have been considered an important element in fluvial transport of toxic metals and organic chemicals. With an aim to serve better understanding environmental behavior of actinides, we performed field observation of discharge of rare earth elements (REE) as analogue to actinides. The major finding from the observation is aquatic humic substances play a dominant role in that discharge. In this JPGU meeting, we report indices of dissolved organic materials that can describe fluvial discharge of rare earth elements appropriately. Tested indices were: (1) the concentration of dissolved organic carbon (DOC), (2) the specific ultraviolet absorption (SUVA), and the fluorescence index (F.I.). As a result, we found that F.I. and especially SUVA can be good indices to explain characteristic increase of concentration of REE in river water in a rainfall event, indicating aromaticity of dissolved HS can be a key aspect in REE discharge with DOM.
Torii, Tatsuo; Sugita, Takeshi*; Tanabe, Sachiko*; Kimura, Yoshihisa*; Kamogawa, Masashi*; Yajima, Kazuaki*; Yasuda, Hiroshi*
no journal, ,
Fluctuations of energetic radiation that were seemed to be caused by a summer thunderstorm activity were observed at the top of Mt. Fuji. The largest of such fluctuations was gradual and lasted for about 20 minutes, and was found to be high-energy 
rays having a continuous energy spectrum up to 10 MeV or more. As for the feature of these fluctuations, it seems naturally that such fluctuations are caused by the bremsstrahlung photons generated by the runaway electrons produced continuously with an intense electric field in the thundercloud rather than originated in the process of lightning discharge. The 5-inch NaI detector used in the observation was so sensitive to photons that it could not have differentiated electrons from photons even if high-energy electrons had been incident upon the detector. When conducting the analysis of energy spectrum, sufficient convergence was achieved in the calculation even in the case where only the sensitivity to photons was considered.
Hattori, Takanori; Abe, Jun; Arima, Hiroshi; Arakawa, Masashi; Komatsu, Kazuki*; Okuchi, Takuo*; Kagi, Hiroyuki; Utsumi, Wataru; Harjo, S.; Ito, Takayoshi
no journal, ,
High-pressure neutron experiments have been limited so far due to the small flux of neutron source. Now, the intense pulse neutron source offered from J-PARC opens up the opportunity. Then, we are trying to do high-pressure neutron experiments, which offers information that have been not obtained so far, such as position of light elements and atomic dynamics. In this talk, we reports first high-pressure TOF results taken at the engineering materials diffractometer TAKUMI in J-PARC, and discuss the future prospect on high-pressure neutron diffraction.
Katayama, Yoshinori
no journal, ,
Recent studies on liquids and amorphous solids under high pressure have revealed a variety of pressure-induced structural changes such as a first-order transition. Intense neutron beam available in J-PARC will open new opportunity for such studies. As one of groups in a project under Grant-in-aid for Scientific Research on Innovative Areas "Earth Science Based on the High Pressure and Temperature Neutron Experiments", liquid group conducts unique study on "Structural change in water and other liquids under high pressure" using a dedicated high-pressure neutron-scattering beamline. The targets are chemically simple systems such as water for which neutron is an irreplaceable probe. Our final goal is novel discoveries in pressure-induced structural changes in liquids. In this talk, both advantages and difficulties in neutron studies on liquids under pressure and expected results will be reviewed.
Utsumi, Wataru; Hattori, Takanori; Arima, Hiroshi; Komatsu, Kazuki*; Abe, Jun; Kagi, Hiroyuki*; Yagi, Takehiko*
no journal, ,
J-PARC (Japan Proton Accelerator Research Complex) started its operation in 2008, and its Materials and Life Science Facility (MLF)opened its public use in December. High flux neutron provided in MLF will definitely be a powerful tool for earth and planetary science. Preliminary high pressure experiments have already started by bringing high pressure devices at the conventional neutron powder beamline. Our proposal submitted to MEXT Grant-in-Aid for New Scientific Area Research entitled "Earth science based on the high pressure and high temperature neutron experiment: project leader Takehiko Yagi" was accepted in 2008, and the construction of high pressure dedicated beamline at J-PARC has been approved. Its conceptual design and construction schedule will be introduced.
Fukazawa, Hiroshi
no journal, ,
I report the present condition and recent topics of a neutron powder diffractometer (Wide Angle Neutron Diffractometer: WAND), which located by our agency on High Flax Isotope Reactor, at Oak Ridge. The WAND is recently used for high pressure and low temperature studies. I report activities of high pressure studies at Oak Ridge and our preliminary results of high-pressure ices obtained by the WAND.
Yokobori, Shinichi*; Yang, Y.*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Yoshimura, Yoshitaka*; Narumi, Issei; et al.
no journal, ,
no abstracts in English