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Iwatsuki, Teruki; Omori, Kazuaki; Shingu, Shinya
no journal, ,
Ultra-filtration for deep groundwater in Mizunami Underground Research Laboratory were carried out to estimate interaction between colloid particle and trace elements. Groundwater sample was collected from fracture of drift wall by using batch tank. The result shows that the colloid particles consist of organics, silicate minerals, ferric hydrates with size of 0.2 micron meter-50 kDa or under 10kDa.
Sueoka, Shigeru; Yamada, Kunimi; Shibata, Kenji; Tsutsumi, Hiroyuki*; Tagami, Takahiro*; Hasebe, Noriko*; Tamura, Akihiro*; Arai, Shoji*
no journal, ,
We are attempting to reveal uplift and denudation history of the Suzuka Range, southwest Japan, by using apatite fission-track and (U-Th)/He thermochronology. The Suzuka Range is distributed along the tectonic boundary of the reverse fault dominant Kinki district and strike-slip fault dominant Chubu district, which is thought to be a reflection of the Philippine Sea Plate slab geometry in this area. We are planning to reconstruct uplift and denudation history of the Suzuka Range in the past few million years and discuss its geomorphological and tectonic implications.
He/
He ratios along seismic source faults in JapanUmeda, Koji; Asamori, Koichi; Kusano, Tomohiro
no journal, ,
It is well known that mantle degassing does not occur homogeneously over the Earth's surface. This study was undertaken to elucidate the geographic distribution of He/He ratios around seismic source faults in Japan, using helium isotope data obtained from gas samples. Several case studies suggest that there is a significant trend of high He emanations along the trace of active faults, resulting in leakage of mantle volatiles through crustal pathways (faults) due to more frequent development of higher permeability pathways and/or upwelling of mantle fluids through the ductile lower crust. From the viewpoint of site selection and implementation of a geological disposal facility, helium isotopes may be regarded as a tool for investigating and/or mapping concealed active faults with no surface expression.
Hanamuro, Takahiro; Takatori, Ryoichi; Yasue, Kenichi; Shibata, Kenji; Umeda, Koji
no journal, ,
no abstracts in English
Yokota, Hideharu; Yoshida, Hidekazu*
no journal, ,
In the view point of safety assessing the geological disposal system for high-level radioactive waste, it is essential to understand mass transportation in a hostrock. Therefore characteristics of mass-transport structures such as flow-path fractures must be understand. In this study, we report formation and the feature of flow-path fractures based on geological observation and fracture mapping in a sedimentary rock at the Horonobe Underground Research Laboratory. In addition, results of thin section observation, element mapping, and isotope analysis of carbonate fillings are shown. These results suggest that he formation process of flow-path fractures includes at least 2 stages; the E-W strike and high angle dip fracture forming stage caused by subsidence and East-West compressive stress and the tension fracture forming stage caused by fracture removement beneath regional uplifting and distressing. This study presents the formation process of flow-path fractures as mass-transport structures in a sedimentary rock. In the future study, we will evaluate changes of flow-path structures from the view point of geological long-term stability.
Tsuyuguchi, Koji; Onoe, Hironori; Takeuchi, Ryuji; Karino, Tomoyuki
no journal, ,
In the 2011 off the Pacific coast of Tohoku Earthquake, groundwater pressure changes were observed around the Mizunami Underground Research Laboratory (MIU) in Tono area. It was confirmed that the tendency of the pressure change due to the earthquake is different according to relationship with the location of borehole and geological feature structure. This report shows the water pressure change observed in boreholes after the earthquake.
Asamori, Koichi; Zhao, D.*
no journal, ,
no abstracts in English
Niwa, Masakazu; Ikuta, Masafumi; Takatori, Ryoichi; Kamataki, Takanobu*; Kurosawa, Hideki*
no journal, ,
Holocene uplift rate of the Miyazaki Plain was estimated based on the elevations and depositional ages of four terrace surface (Shimotajima I to IV surfaces; Nagaoka et al., 1991). However, age data are still poor except for the Shimotajima I surface. We report new data of detailed description of abandoned lagoon sediments of the Shimotajima II to IV surfaces.
Ikuta, Masafumi; Niwa, Masakazu; Takatori, Ryoichi; Kurosawa, Hideki*; Kosaka, Hideki*
no journal, ,
Although there are several normal faults in coastal area on the Pacific side, normal faulting triggered by a large earthquake in plate convergence has never been reported until the earthquake in Fukushima, April 11, 2011. Therefore more case studies focused on normal faults are needed to assess the risk of fault activity in coastal areas. As such case study, we are doing geological and topographical surveys in the Kawaminami Fault, lying along the northern margin of the Miyazaki Plain.
Karino, Tomoyuki; Tsuyuguchi, Koji; Onoe, Hironori; Takeuchi, Ryuji
no journal, ,
Japan Atomic Energy Agency (JAEA) has been conducting Mizunami Underground Research Laboratory (MIU) Project. The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III), with a total duration of 20 years. Currently, the project is being carried out under the Phase II. One of the Phase II goals is set to develop and revise models of the geological environment using the investigation results obtained during excavation, and determine and assess the changes in the geological environment in response to excavation. The long term hydro-pressure monitoring has been continued to achieve the Phase II goals. In this paper, a part of the result of long-term hydro-pressure monitoring during the URL excavation in Phase 2 of MIU project were introduced.
Sato, Tatsuhiko; Yasuda, Hiroshi*; Kataoka, Ryuho*; Yashiro, Seiji*; Kuwabara, Takao*; Shiota, Daiko*; Kubo, Yuki*
no journal, ,
When solar energetic particles (SEP) are incident to the atmosphere, they can induce air showers by generating varieties of secondary particles. Such secondary particles can reach the deep into the atmosphere, and enhance the level of radiation doses. This can be a hazard of aircrews. In order to precisely estimate the radiation doses during large solar particle events, we are developing a warning system of aviation exposure to SEP, WASAVIES. The WASAVIES has been tested and verified by making a comparison between the measured and calculated count rates of several neutron monitors during past GLE (ground level enhancement) events. The final goal of our project is to predict the enhancement of radiation doses due to SEP exposure within 6 hours from the GLE onset.
Sanada, Yukihisa; Torii, Tatsuo; Yokoyama, Ryuzo*
no journal, ,
he Great East Japan Earthquake on March 11, 2011 generated a series of large tsunami waves that resulted serious damage to the Fukushima Daiichi Nuclear Power Plant (NPP) and radioactive materials were discharged to the environment. The aerial radiation monitoring has measured the ambient dose-rate and radiocesium deposition in large areas including those above the forest and the high mountain which people couldn't enter easily on foot or by vehicles, it is useful for grasping the distribution of contamination. In recent years, a stereoscopic slope mapping method has developed by the progress in analysis using digital elevation model (DEM) and being used widely. In this research, we tried to analyze in visible clearly about the distribution of the radiocesium deposition by lapping the ARM results over the stereoscopic slope map.
Niizato, Tadafumi; Abe, Hironobu; Watanabe, Takayoshi; Yasue, Kenichi; Oda, Yoshihiro; Sato, Haruo
no journal, ,
no abstracts in English
Hattori, Takanori; Sano, Asami; Arima, Hiroshi*; Komatsu, Kazuki*; Yamada, Akihiro*; Nagai, Takaya*; Katayama, Yoshinori; Inoue, Toru*; Utsumi, Wataru; Kagi, Hiroyuki*; et al.
no journal, ,
The PLANET is the world's first neutron beamline specialized for high-pressure and high-temperature experiments. The most characteristic feature is the capability to investigate the state of the matter at high-pressure and high-temperatures up to 20 GPa and 2000 K with the multi-anvil high-pressure apparatus. The construction was started in 2008. The beamline was commissioned in the first half year of JFY 2012 and the new data is being taken by project members. This year, the beamline is reborn to a public beamline of J-PARC. In this talk, the performance of the PLANET and the typical results are introduced. The resolution of the diffraction pattern (
d/d=c.a 0.6%) was found to be almost equal to the designed value (0.5%). The elimination of the background from the sample surrounding materials, which is the most important feature of the high-pressure experiments, was found to be accomplished with the use of the severe incident collimator and radial receiving collimator system. The beamline is opened for general users since the last half year of JFY2013 (from Feb.).
Katayama, Yoshinori; Hattori, Takanori; Yagafarov, O.*; Saito, Hiroyuki; Sano, Asami; Suzuya, Kentaro; Chiba, Ayano*
no journal, ,
As the first high-pressure experiments on structurally disordered materials using a new high-pressure neutron diffractometer, PLANET, installed in J-PARC/MLF, measurements of silica glass were caried out. We compressed a sample in a ZrO
cube using a six-axis press and measured diffraction at pressures of 0.1 MPa, 2.3, 5.5, 7.5 and 9.9 GPa at room temperature. The size of the sample was 4.6 mm in diameter and 6.7 mm in height. The size of the incident beam was 2.5 mm in width and 4.5 mm in height. The pressure was estimated from the applied load. Vanadium sample and empty cell were also measured for the correction of the diffraction intensity. Clean diffraction patterns without diffraction lines from surrounding materials were obtained thanks to the radial collimator system. Measurements on heavy water at room temperature, 100
C and 200C at 0.8 GPa were also carried out. Significant temperature dependence of diffraction pattern was observed.
Abe, Jun; Sekine, Kotaro*; Harjo, S.; Gong, W.; Aizawa, Kazuya
no journal, ,
In order to utilize underground environment, e.g. CCS, accurate estimate of crustal stress is indispensable. Rock sample might have residual strain corresponding to crustal stress the sample was taken. Neutron diffraction measurements of the rock sample have been performed, and we have attempted to analyze residual strain in the sample. It was speculated that quartz grains contain tensile strain, on the other; feldspar grain contains compression strain. Residual strain in the rock sample might become helpful to estimate states of the crustal stress where the sample was taken. Therefore, it is expected that strain measurements using neutron diffraction serve to understanding of stress state in underground environment.
Sano, Asami; Nagai, Takaya*; Iizuka, Riko*; Seto, Yusuke*; Kuribayashi, Takahiro*; Hattori, Takanori
no journal, ,
Lawsonite is a hydrous mineral which is considered as a main carrier of hydrogen in the subtucting slab. Previous single crystal X-ray diffraction and neutron diffraction studies indicate that there exist two phase transitions at low temperature. A property of low temperature is sometimes considered to be equivalent to the behavior at high pressure, and some studies pointed out the possibility of transition at high pressure. To investigate the pressure response of hydrogen bond and phase transition in lawsonite, neutron diffraction experiment was conducted. High pressure and high temperature neutron diffraction experiment was conducted by 6-ram press at J-PARC MLF. Using 6-6 type anvil with TEL size of 10 mm, neutron diffraction pattern was corrected up to 6 GPa and 800
C. In addition, hydrostatic experiment at ambient pressure was conducted using Paris-Edinburgh press. New peak was observed at 1.83
that indicates phase transition at high pressure.