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Nakanishi, Toshimichi*; Komatsu, Tetsuya; Ogata, Manabu; Kawamura, Makoto; Yasue, Kenichi*
Gekkan Chikyu "Kiso deta Kara Kangaeru Dai Yonkigaku No Shintenkai-I" Gogai No.71, p.148 - 155, 2022/02
The formation process of terrace topography was investigated by observing and analyzing boring core samples collected in the middle reaches of the Kumano River. It was assumed that the older terrace topography was distributed higher than the current riverbed surface. However, since tributary debris flow deposits may be thickly distributed beneath the old gyre river valley, care must be taken when using the surface of the ground as an index of uplift and erosion.
Shimo, Michito*; Niwa, Masakazu; Miyakawa, Kazuya; Yasue, Kenichi*; Tonokura, Kenichi*; Tokunaga, Tomochika*
Fukada Chishitsu Kenkyujo Nempo, (23), p.21 - 34, 2022/00
no abstracts in English
Yonaga, Yusuke; Sano, Naomi*; Amamiya, Hiroki*; Ogita, Yasuhiro; Niwa, Masakazu; Yasue, Kenichi*
Oyo Chishitsu, 62(1), p.2 - 12, 2021/04
Provenance analysis based on quick identification of heavy minerals using an electron probe microanalyzer (EPMA) was applied to samples from Pleistocene sediments in Horonobe region, Hokkaido, where major provenance rocks can be sedimentary and mafic igneous rocks. The concentrations of 16 elements were measured in individual grains to identify the mineral species based on their chemical composition. In addition, microscopic observation of thin sections and gravel composition analysis were conducted to confirm the validity of the quick identification of heavy minerals. These analyses clarify that combinations of several heavy mineral species can be a useful index of provenance rocks from the Soya Hill and Teshio Mountains, and suggest that uplift of the Soya Hill after ca. 1.5 Ma constrained supply of sediments from the Teshio Mountains. On the other hand, minerals uncommon both in the Soya Hill and Teshio Mountains, such as hornblende, are included in the Pleistocene sediments. This suggests that a sediment supply from distant area was also significant, like transportation by the Teshio River. The method for quick identification of heavy minerals using EPMA can provide an information about provenance rocks difficult to identify only by gravel composition analysis.
Niwa, Masakazu; Amamiya, Hiroki*; Yonaga, Yusuke; Ogita, Yasuhiro; Yasue, Kenichi*; Iwano, Hideki*; Danhara, Toru*; Hirata, Takafumi*
Chishitsugaku Zasshi, 126(5), p.267 - 283, 2020/05
U-Pb and fission-track (FT) ages from single zircon grain were measured for three tephra samples (TKB3, TKB6, and TKB7) intercalated in Neogene to Quaternary in Horonobe area, Hokkaido, to understand their depositional ages. In TKB3 and TKB6, weighed average U-Pb and FT ages for zircon grains within the youngest age range are coincident within a range of error 2 each other, which suggest that their ages correspond to the eruption ages. In TKB7, FT ages for most zircons are reset to their U-Pb ages or younger. The weighed average FT age for all analyzed zircons and weighed average U-Pb age for zircon grains within the youngest age range are coincident within a range of error 2
each other. Thus, their ages could also show the eruption age.
Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06
In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.
Shimizu, Mayuko; Sano, Naomi; Ueki, Tadamasa; Komatsu, Tetsuya; Yasue, Kenichi*; Niwa, Masakazu
Island Arc, 28(2), p.e12295_1 - e12295_13, 2019/03
Times Cited Count:3 Percentile:13.10(Geosciences, Multidisciplinary)no abstracts in English
Ishimaru, Tsuneari; Yasue, Kenichi*; Asamori, Koichi; Kokubu, Yoko; Niwa, Masakazu; Watanabe, Takahiro; Yokoyama, Tatsunori; Fujita, Natsuko; Saiga, Atsushi; Shimizu, Mayuko; et al.
JAEA-Research 2018-008, 83 Pages, 2018/12
This annual report documents the progress of research and development (R&D) in the 2nd fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.
Nomura, Katsuhiro; Tanikawa, Shinichi*; Amamiya, Hiroki; Yasue, Kenichi
JAEA-Data/Code 2016-015, 49 Pages, 2017/03
The uplift of the last hundred thousand years in the Japanese Islands has been acquired mainly using marine and river terraces. We arranged information regarding the uplift in a table. This data is one of the useful information for the development of the investigation technology of uplift and for the research of the landform evolution in Japanese islands.
Sueoka, Shigeru; Shimada, Koji; Ishimaru, Tsuneari; Niwa, Masakazu; Yasue, Kenichi; Umeda, Koji*; Danhara, Toru*; Iwano, Hideki*
Journal of Geophysical Research; Solid Earth, 122(3), p.1848 - 1859, 2017/03
no abstracts in English
Tokuyasu, Kayoko; Yasue, Kenichi; Komatsu, Tetsuya; Tamura, Itoko; Horiuchi, Yasuharu
QST-M-2; QST Takasaki Annual Report 2015, P. 189, 2017/03
Understanding the stage of mountain building is crucial to the stability assessment of geological environments in geological disposal system. In this context, we have carried out the research and development of provenance analysis techniques to elucidate the mountain-building stage. Here we present the results focusing on the R&D using the Electron Spin Resonance (ESR) signals from quartz in sediments and their basement rocks.
Ishimaru, Tsuneari; Umeda, Koji*; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Yokoyama, Tatsunori; Fujita, Natsuko; Shimizu, Mayuko; et al.
JAEA-Research 2016-023, 91 Pages, 2017/02
This annual report documents the progress of research and development (R&D) in the 1st fiscal year during the JAEA 3rd Mid- and Long-term Plan (fiscal years 2015-2021) to provide the scientific base for assessing geosphere stability for long-term isolation of the high-level radioactive waste. The planned framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. In this paper, the current status of R&D activities with previous scientific and technological progress is summarized.
Sueoka, Shigeru; Shimada, Koji; Ishimaru, Tsuneari; Niwa, Masakazu; Yasue, Kenichi; Umeda, Koji*; Danhara, Toru*; Iwano, Hideki*
Fuisshon, Torakku Nyusureta, (29), p.5 - 7, 2016/12
no abstracts in English
Ishimaru, Tsuneari; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Yokoyama, Tatsunori; Fujita, Natsuko; Shimizu, Mayuko; Hama, Yuki
JAEA-Review 2016-016, 44 Pages, 2016/08
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in JAEA, in fiscal year 2016. The objectives and contents in fiscal year 2016 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Hama, Katsuhiro; Sasao, Eiji; Iwatsuki, Teruki; Onoe, Hironori; Sato, Toshinori; Fujita, Tomoo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Takeda, Masaki; Aoyagi, Kazuhei; et al.
JAEA-Review 2016-014, 274 Pages, 2016/08
We synthesized the research results from the Mizunami/Horonobe Underground Research Laboratories (URLs) and geo-stability projects in the second midterm research phase. This report can be used as a technical basis for the Nuclear Waste Management Organization of Japan/Regulator at each decision point from siting to beginning of disposal (Principal Investigation to Detailed Investigation Phase).
Sueoka, Shigeru; Umeda, Koji; Yasue, Kenichi; Niwa, Masakazu; Shimada, Koji; Ishimaru, Tsuneari; Danhara, Toru*; Iwano, Hideki*; Yagi, Koshi*
Chigaku Zasshi, 125(2), p.201 - 219, 2016/04
We applied multi-system thermochronology to the Tsuruga body of the Kojaku granite to constrain the cooling/denudation history of the Tsuruga area. Based on the thermochronometric results and other data, we reconstructed the cooling and denudation histories of the Tsuruga body as below: (1) the Tsuruga body intruded at c.a. 68 Ma at the depth of 4-5 km, (2) rapidly cooled down to c.a. 200C by heat conduction within a few million years or less, and (3) slowly cooled due to peneplanation during the Cenozoic. This cooling/denudation history is consistent with the observations that cataclasite and fault gouge are dominant in the crush zones of the Tsuruga body, that similar slow cooling histories over the Cenozoic are estimated in the surrounding areas based on thermochronometric ages, and that the amount of denudation in the last few million years in the Tsuruga area is inferred at less than several hundred meters from the elevations of the uplifted peneplains.
Tanikawa, Shinichi; Sanga, Tomoji*; Yasue, Kenichi
Chikei, 37(2), p.189 - 207, 2016/04
JP, 2009-239446Existing simulation methods of long-term fluvial processes, represented as conventional difference scheme of diffusion equation, cannot control about the expression of sediment transportation satisfactorily, particularly around confluences in middle and lower reach of the river. To address this, we newly developed a numeral model and simulation program of fluvial processes, in which sediment outflux is distributed to multiple grids with the formula that enlarges the fluvial transport efficiency downstream as a function of grain-size and drainage area (named "transport distance increment curve"). This formula can control the concavity of longitudinal profile. With this model, analyses about expressions of geomorphic development in longitudinal river profile were carried out. As a result, it was confirmed that, with accurate settings of parameters, this model can yield features of river profiles, considering sediment transportation around confluences. It is believed from the above that this model enables the expression of fluvial topography as seen in nature, by translating the concept of long-term fluvial process into parameters.
Niwa, Masakazu; Shimada, Koji; Tamura, Hajimu*; Shibata, Kenji*; Sueoka, Shigeru; Yasue, Kenichi; Ishimaru, Tsuneari; Umeda, Koji*
Clays and Clay Minerals, 64(2), p.86 - 107, 2016/04
Times Cited Count:11 Percentile:34.63(Chemistry, Physical)no abstracts in English
Umeda, Koji; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Fujita, Natsuko; Shimizu, Mayuko; Matsubara, Akihiro; Tamura, Hajimu; Yokoyama, Tatsunori; et al.
JAEA-Review 2015-019, 42 Pages, 2015/09
This report is a plan of research and development (R&D) on geosphere stability for long-term isolation of high-level radioactive waste (HLW) in JAEA, in fiscal year 2015. The objectives and contents in fiscal year 2015 are described in detail based on the outline of 7 years plan (fiscal years 2015-2021). Background of this research is clarified with the necessity and the significance for site investigation and safety assessment, and the past progress in this report. In addition, the plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Umeda, Koji; Yasue, Kenichi; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Fujita, Natsuko; Shimizu, Mayuko; Shimada, Akiomi; Matsubara, Akihiro; Tamura, Hajimu; et al.
JAEA-Review 2015-012, 43 Pages, 2015/08
The concept of geological disposal of high-level radioactive waste (HLW) in Japan is based on a multibarrier system which combines a stable geological environment with an engineered barrier system. Potential geological host formations and their surroundings are chosen, in particular, for their long-term stability, taking into account the fact that Japan is located in tectonically active zone. This report is to outline 7 years plan (fiscal years 2015-2021) of research and development (R&D) for geosphere stability for long-term isolation of the HLW in JAEA. Background of this research is clarified with the necessity and the significance, and the past progress in this report. The objectives, outline, contents and schedule during the next 7 years are described in detail. In addition, the plan framework is structured into the following categories: (1) Development and Systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques.
Hama, Katsuhiro; Mizuno, Takashi; Sasao, Eiji; Iwatsuki, Teruki; Saegusa, Hiromitsu; Sato, Toshinori; Fujita, Tomoo; Sasamoto, Hiroshi; Matsuoka, Toshiyuki; Yokota, Hideharu; et al.
JAEA-Research 2015-007, 269 Pages, 2015/08
We have synthesised the research results from Mizunami/Horonobe URLs and geo-stability projects in the second mid-term research phase. It could be used as technical bases for NUMO/Regulator in each decision point from sitting to beginning of disposal (Principal Investigation to Detailed Investigation Phase). High quality construction techniques and field investigation methods have been developed and implemented and these will be directly applicable to the National Disposal Program (along with general assessments of hazardous natural events and processes). It will be crucial to acquire technical knowledge on decisions of partial backfilling and final closure by actual field experiments in Mizunami/Horonobe URLs as main themes for the next phases.