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Iwatsuki, Teruki; Yoshida, Haruo; Onuki, Toshihiko; Kozai, Naofumi
no journal, ,
Chemical condition and trace elements concentration in groundwater were analyzed by ultra filtration methods at Horonobe area, Hokkaido Island to estimate the colloid transport process of trace elements. The physico-chemical phases of trace element were classified into following three types; (1) trace elements which has unclear size dependency, (2) solute phase or the particle phase less than 10,000 MV, (3) solute phase and particle phase larger than 10,000 MV.
Niwa, Masakazu; Shimada, Koji; Kurosawa, Hideki; Ishimaru, Tsuneari; Kosaka, Hideki*
no journal, ,
Significantly high concentrations of hydrogen gas have been observed at active faults. Experimental studies have suggested that such hydrogen gas is generated by a radical reaction due to rock fracturing caused by fault activity. In this study, we tried multipoint hydrogen gas measurements along a fault zone crosscutting an active fault, to elucidate a path of hydrogen gas in fault zones. The result of the mesurements indicate that the hydrogen gas is transferred in the breccia and cataclasite of relatively-high permeability rather than in the smectite-rich fault gouge of low permeability, and strongly supports the hypothesis that a path of the hydrogen gas derived from fault activity is controlled by advective flow with groundwater.
He/
He ratios of hot springs on the Noto Peninsula, Central JapanUmeda, Koji; Ninomiya, Atsushi; Negi, Tateyuki
no journal, ,
no abstracts in English
Saito, Tatsuo; Umeda, Koji
no journal, ,
We estimated magma reservoir structure and settlement age under Onikobe-Naruko volcano with simulation code based upon energy and mass conservation law to research the time evolution process of heat and liquid fluid system after magma intrusion. Magma intrusion model was follows: (1)Under Onikobe-Naruko volcano (depth: 5-20km, parameter 1st), (2)Spherical shape (radius: 2-6.5km, parameter 2nd), (3)Only one magma intrusion and reservoir, (4)Analyze parameters to match the calculated thermostructure with the cutoff depth and the data of drill holes around the volcano (i.e. heat flux, measured temperature data). According to optimization of these parameters, the magma reservoir intruded into 15km under Onikobe-Naruko volcano, and has 6.5km radius, 30 thousand years ago.
Shimada, Koji; Tanaka, Hidemi*; Hirokawa, Tomotaka*; Saito, Tomohiko*; Tsunomori, Fumiaki*
no journal, ,
no abstracts in English
Hanamuro, Takahiro; Umeda, Koji; Maeda, Katsuhiko*
no journal, ,
K-Ar dating, fission track (FT) dating, and thermoluminescence (TL) dating of altered samples are executed in order to understand the alteration age of geothermal activities in the southern part of Kii Peninsula. Besides, in order to understand the temperature and chemistry of hydrothermal solution, fluid inclusion analyses of altered minerals from the alteration zones around gushing out points of the hot springs and mineralization area, are executed. Results of dating, K-Ar age of sericite seems to show the forming age of sericite by high-temperature hydrothermal alteration, and the hydrothermal activities seem to have relation to the volcanic activities. Apatite FT age seems to show the reset age by burying after sedimentation (ca. 10 Ma) and the reset age by low-temperature geothermal activities at Tosenji and Yunomine (2.5
5 Ma). Results of fluid inclusion analyses, hydrothermal solution of middle to high temperature (
200 
C) and middle to high salinity (1 wt%NaCl) are identified. Moreover, at Heijigawa area, hydrothermal solution of low temperature (180 degree C) and low salinity (0.5 wt%NaCl) are identified, too. This hydrothermal solution of low temperature and low salinity is thought to be the same kind of the solution by the low-temperature geothermal activities at Tosenji and Yunomine.
Tajikara, Masayoshi; Yasue, Kenichi; Yanagida, Makoto*; Sugai, Toshihiko; Morita, Yoshimune*; Furusawa, Akira*
no journal, ,
no abstracts in English
Yoshida, Haruo; Hama, Katsuhiro; Iwatsuki, Teruki
no journal, ,
no abstracts in English
Negi, Tateyuki; Umeda, Koji; Asamori, Koichi
no journal, ,
MT-survey is used to be applied to the investigation of the geothermal resource, mineral resource, and oil. In recent years MT-survey has also been recognized as an effective method for the investigation of deep geological environments. However, due to the nature of magnetotulluric source, it is difficult to maintain data quality at all time in extremely noisy environment. Furthermore, expansion of urban area will provide an opportunity to acquire MT data in such environment. Therefore, it is important to be able to evaluate the quality of acquired data numerically in order to evaluate the reliability of inversion result. We show the new method of the quality assessment of MT data, its effect to the inversion result, and the new method of the reliability assessment of MT inversion results.
Yamada, Kunimi; Hanamuro, Takahiro; Tagami, Takahiro*; Yamada, Ryuji*; Umeda, Koji
no journal, ,
In 1987, it was revealed that the (U-Th)/He ages of apatites might be cooling ages with very low temperature cooling. Because of the suggested useful possibility in geo- and thermochronology, the (U-Th)/He method has been quickly developed since 1990's. The (U-Th)/He method mainly applies to investigate the last event on a cooling or exhumation history of present rapid orogen and a thermal anomaly through an active fault at the present. Japan Atomic Energy Agency have jointly set up the lab of the (U-Th)/He dating in cooperation with Kyoto University and NIED. At the present stage, the accuracy and precision are roughly 20 and 10%, respectively, using the age known zircon from the Fish Canyon Tuff (FC3). In the presentation, we will introduce the ages of some age known samples.
Ishimaru, Tsuneari; Niwa, Masakazu; Shimada, Koji; Kurosawa, Hideki; Moriya, Toshifumi*
no journal, ,
Fault activity causes deformation and mechanical damage, and subsequent change in the groundwater flow, to the surrounding rocks. For the site selection of underground repositories of high-level radioactive waste, describing the spatial distribution and characteristics of topographic lineaments, crush zones and fractures concerning fault activity is essential for the assessment of long-term stability of geological environment in the investigation area. As regarding fault crush zones, their spatial distribution is constrained by the heterogeneity of fault geometry such as stepover, and their characteristics is involved in their permeability structure. Here, we present the procedure and result of the geological survey in the western part of the Atotsugawa Fault, Gifu Prefecture, which is practiced a case study focused on the spatial distribution and characteristics of fault crush zones.
Ninomiya, Atsushi; Umeda, Koji; Negi, Tateyuki
no journal, ,
Although no Quaternary volcano are distributed on the Asahi Mountains, an anomalous conductive body is imaged beneath the Asahi Mountains with MT method. The low-frequency earthquakes around the body indicate that the body is due to a magma storage. Crustal earthquakes in the granite close to the magma are caused by fracturing of the granite due to infiltration of the fluid released from the magma. There are two belts of active faults on the eastern edge of the Asahi Mountains. The crustal earthquakes are active beneath the Yamagata Basin faults and are not active beneath the western Nagai Basin faults. The high He isotope ratio from the hot spring gases on the Asahi Mountains and the Yamagata Basin faults indicate effective supply of He from the magma. On the other hand low He isotope ratio imply that the western Nagai Basin faults do not work as a conduit of He from the magma.
Uehara, Shinichi*; Shimamoto, Toshihiko*; Funaki, Hironori; Niizato, Tadafumi; Kurikami, Hiroshi; Onishi, Yuzo*; Matsumoto, Takuma*
no journal, ,
Determination of underground transport properties is needed in modeling underground fluid flow, which is critically important in many problems such as fluid circulation, waste isolation, and carbon dioxide sequestration. Estimation of deep underground permeability structures is extremely difficult because transport properties of rocks are affected dramatically with fractures and fault zones and yet we do not know how to evaluate the effects of these structures on hydraulic properties distribution in depth. In-situ tests cannot provides transport properties at depths deeper than drill holes, whereas laboratory measurements can be done easily under conditions even deeper than 10 km as long as samples are available. Their applicability, however, to estimate real underground hydraulic structures is uncertain. Therefore, one should seek for a way of using laboratory and in-situ data complementary.
Asamori, Koichi; Kunitomo, Takahiro; Nakajima, Takahiro; Ohara, Hidefumi*; Shigeta, Naotaka; Watanabe, Toshiki; Kumazawa, Mineo
no journal, ,
The electromagnetic (EM) and seismic ACROSS have been installed around the Horonobe Underground Research Laboratory and experimental monitoring prior to the construction of the underground facilities was started. The EM and seismic ACROSS are consisted a transmitter and 3 receiver stations. These receivers are about 1-2 km away from the transmitter. The observed spectrum by operating ACROSS show that the amplitude of frequency bands correspond to the transmitted signal are higher than that of other frequency bands. It is indicates that the transmitted signal was certainly received.
Maekawa, Keisuke; Niizato, Tadafumi; Kurikami, Hiroshi; Asamori, Koichi; Imai, Hisashi*; Shiozaki, Isao*
no journal, ,
no abstracts in English
Tokiwa, Tetsuya; Asamori, Koichi; Niizato, Tadafumi; Yasue, Kenichi; Abe, Hironobu; Maekawa, Keisuke
no journal, ,
In this report, we suggest the data flow for understanding of activities, history and occurrence of faults. This data flow mainly consists of data items and survey items, and shows a correlation among them. After we apply information on the Omagari Fault to this flow as case study, this flow indicates that recent activity of the Omagari Fault remains unanswered. This data flow is very informative for extracting insufficient data to understand the activities, history and occurrence of fault.
Yasue, Kenichi; Tajikara, Masayoshi; Saegusa, Hiromitsu; Niwa, Masakazu; Kurosawa, Hideki; Kusano, Tomohiro
no journal, ,
The stability of geological environments is influenced by natural events such as uplift, denudation, and climate variation. It is important for the geological disposal of nuclear wastes to assess the stability of geological environments. The purpose of this study is to establish the comprehensive techniques and method to evaluate the effects of topographic and climatic variations on groundwater flow condition. For this purpose, we developed the following techniques. (1) Research techniques for paleo-topography and paleo-climate (2) Modeling and simulation techniques for landform development (3) Simulation techniques of groundwater flow in consideration of the time-variation of geological environment. In this presentation, we introduce briefly the some of research results.
Kawamura, Makoto; Oi, Takao; Niizato, Tadafumi; Yasue, Kenichi; Makino, Hitoshi; Ishimaru, Tsuneari; Sasao, Eiji; Umeda, Koji; Seo, Toshihiro; Yanagawa, Harunaga*; et al.
no journal, ,
no abstracts in English
Kawamura, Makoto; Oi, Takao; Kato, Tomoko; Yasue, Kenichi; Niizato, Tadafumi; Tokiwa, Tetsuya; Makino, Hitoshi; Ishimaru, Tsuneari; Umeda, Koji; Sasao, Eiji
no journal, ,
no abstracts in English
Murakami, Makoto*; Kawamura, Makoto; Oi, Takao; Makino, Hitoshi; Nishimura, Takuya*; Umeda, Koji; Seo, Toshihiro
no journal, ,
no abstracts in English