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Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Ogawa, Hiroki; Hakoiwa, Hiroaki; Watanabe, Tsuyoshi; Nishiyama, Nariaki; Yokoyama, Tatsunori; Ogata, Manabu; et al.
JAEA-Research 2023-005, 78 Pages, 2023/10
JAEA-Research-2023-005.pdf:6.51MB
This annual report documents the progress of research and development (R&D) in the 1st fiscal year of the Japan Atomic Energy Agency 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. 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. The current status of R&D activities with previous scientific and technological progress is summarized.
Nishiyama, Nariaki; Goto, Akira*; Tsukahara, Yuzuko; Kawamura, Makoto; Umeda, Koji*; Niwa, Masakazu
JAEA-Testing 2022-003, 51 Pages, 2022/09
JAEA-Testing-2022-003.pdf:5.24MB
JAEA-Testing-2022-003-appendix(CD-ROM).zip:1.12MB
Advancement of the evaluation technology of the magma activity range is essential as one of the technical issues related to volcanic and igneous activities in the evaluation of the long-term stability of the geological environment in the geological disposal of high-level radioactive waste. As an effective method, topographical analysis of volcanic edifices is expected to be used to determine the distribution area of dikes. In recent years, the development of computer-based topographic analysis technology has made it possible to simply perform a large volume of work that would otherwise be difficult due to the manual handling. This report describes an analysis method for the shape of contour lines that forms volcanic edifices using GIS software.
Sasao, Eiji; Ishimaru, Tsuneari; Niwa, Masakazu; Shimada, Akiomi; Shimada, Koji; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; Ogita, Yasuhiro; et al.
JAEA-Review 2022-022, 29 Pages, 2022/09
JAEA-Review-2022-022.pdf:0.97MB
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 Japan Atomic Energy Agency (JAEA), in fiscal year 2022. The objectives and contents in fiscal year 2022 are described in detail based on the JAEA 4th Medium- and Long-term Plan (fiscal years 2022-2028). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. 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
Ishimaru, Tsuneari; Ogata, Nobuhisa; Kokubu, Yoko; Shimada, Koji; Niwa, Masakazu; Shimada, Akiomi; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; et al.
JAEA-Research 2021-007, 65 Pages, 2021/10
JAEA-Research-2021-007.pdf:4.21MB
This annual report documents the progress of research and development (R&D) in the 6th 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. The current status of R&D activities with previous scientific and technological progress is summarized.
Ishimaru, Tsuneari; Kokubu, Yoko; Shimada, Koji; Shimada, Akiomi; Niwa, Masakazu; Watanabe, Takahiro; Sueoka, Shigeru; Yokoyama, Tatsunori; Fujita, Natsuko; Ogita, Yasuhiro; et al.
JAEA-Review 2021-012, 48 Pages, 2021/08
JAEA-Review-2021-012.pdf:1.64MB
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 Japan Atomic Energy Agency (JAEA), in fiscal year 2021. The objectives and contents in fiscal year 2021 are described in detail based on the JAEA 3rd Medium- and Long-term Plan (fiscal years 2015-2021). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. 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.
Ishimaru, Tsuneari; Ogata, Nobuhisa; Shimada, Koji; Kokubu, Yoko; Niwa, Masakazu; Asamori, Koichi; Watanabe, Takahiro; Sueoka, Shigeru; Komatsu, Tetsuya; Yokoyama, Tatsunori; et al.
JAEA-Review 2020-010, 46 Pages, 2020/07
JAEA-Review-2020-010.pdf:1.89MB
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 Japan Atomic Energy Agency (JAEA), in fiscal year 2020. The objectives and contents in fiscal year 2020 are described in detail based on the JAEA 3rd Medium- and Long-term Plan (fiscal years 2015-2021). In addition, the background of this research is described from the necessity and the significance for site investigation and safety assessment, and the past progress. 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.
Tsukahara, Yuzuko; Kanno, Mizuho; Goto, Akira; Fujita, Natsuko; Komatsu, Tetsuya; Maemoku, Hideaki*
no journal, ,
Holocene crustal movements are recorded as fossil calcareous assemblages on rocky coast. It is possible to reconstruct crustal movements by summarizing these heights, structures and 
C ages. In this study, to clarify crustal movements, we collected calcareous assemblages and dated them using the C at Cape Hane. C ages show forming period of the lowest wave-cut-bench. However, it is difficult to determine the history of emerged events in a short cycle. To reconstruct the crustal movement history precisely, it is necessary to identify obvious multi-layer structures or discontinuous surfaces with time interval.
Ogata, Manabu; Tsukahara, Yuzuko; Kawamura, Makoto; Kanno, Mizuho; Nishiyama, Nariaki*; Sueoka, Shigeru; Komatsu, Tetsuya; Nakanishi, Toshimichi*; Yasue, Kenichi*
no journal, ,
Optically stimulated luminescence (OSL) dating method on feldspar is useful to date sediments on geomorphological time scale. In this presentation, we present the case studies for marine terraces in the Noto Peninsula and abandoned river valleys along the Oi River, for which the emergence ages were estimated by using feldspar OSL dating. This study was carried out as a part of the establishment of advanced technology for estimation of uplift rates using emergence ages of emergent landforms project.
Tsukahara, Yuzuko; Ogata, Manabu; Kawamura, Makoto; Kanno, Mizuho*; Nishiyama, Nariaki; Sueoka, Shigeru; Nakanishi, Toshimichi*; Komatsu, Tetsuya
no journal, ,
One hundred thousand-year-scale uplift rate of the Japanese mountains is estimated mainly based on the Terrace to Terrace method (TT method; Yoshiyama and Yanagida, 1995). To apply the TT method, it is necessary to identify the pair of the sedimentary terraces of the last glacial period and the one before last glacial period. However, there are many mountains where such terrace pairs are not recognized. Therefore, as an alternative method to the TT method, we suggest the method based on landforms and deposits of incised meandering rivers (for example, Yasue et al., 2014; Ogata et al., 2021). In this presentation, we will report the results of a survey conducted in the middle of the Oi River as part of such research.
Komatsu, Tetsuya; Hongo, Misao*; Furusawa, Akira*; Tsukahara, Yuzuko; Kawamura, Makoto; Nishiyama, Nariaki; Kanno, Mizuho*; Yasue, Kenichi*
no journal, ,
Elucidating formation ages of marine terraces located higher than that correlated with Marine Isotope Stage (MIS) 5e, so-called higher marine terraces, is a key to understand the uplift rate over a period longer than ~100,000 years. To acquire knowledge about chronological limitation of higher marine terraces, we conducted a case study in the northern side of Nanao Bay, Noto Peninsula, where higher marine terraces are well-preserved in Japan. Cryptotephra and pollen analysis of terrace-forming material was carried out in a higher-marine terrace, previously correlated with MIS 13 estimated from its morphostratigraphical position. The results suggest that the higher marine terrace was created during an interglacial period before MIS 19, possibly MIS 21.
Ogata, Manabu; Tsukahara, Yuzuko; Nishiyama, Nariaki; Komatsu, Tetsuya; Uchida, Mao; Kawamura, Makoto; Ishihara, Takanori; Nakanishi, Toshimichi*
no journal, ,
Terrace to terrace (TT) method is mainly used for estimating uplift rate on mountain areas of Japan on 10
-year time scale. However, this method cannot be applied to the area with poor distribution of fluvial terraces. In such area, the method based on the emergence ages of the fluvial landform, e.g., an abandoned river valley around a cutoff spur, and the relative elevation between old and present reiver bed is expected instead of TT method. This method calculates the river-incision rate by dividing the relative elevation by the emergence age. The river-incision rate is equal to the uplift rate if the river is at equilibrium (graded stream). We are investigating the fluvial landform in the Oi River basin for verifying this method. In this presentation, we will present the incision and uplift rate estimated by feldspar OSL dating results.
Tsukahara, Yuzuko; Saito, Toshihito*; Nakanishi, Toshimichi*; Nishiyama, Nariaki; Fujita, Natsuko; Kawamura, Makoto; Umeda, Koji*
no journal, ,
Paleo-sea levels estimated from the elevation and age of emerged shoreline features and fossil calcareous assemblages are one of the useful tools for reconstructing the tectonic features of the Holocene. In this study, we reconstruct the paleo-sea levels around the eastern part of Izu Peninsula using fossil calcareous assemblages to verify case studies in areas with active volcanism and seismic activity. In addition, we will infer the characteristics of crustal deformation through comparison with previous studies. Shishikura et al. (2023) surveyed emerged shoreline features and fossil calcareous assemblages around the coast in the vicinity of Ito, the northeastern part of the Izu Peninsula, to clarify the emerged process. They concluded that the cause of the emergence is associated with a volcanotectonic uplift due to subsurface magma movement. In order to verify the representativeness of this crustal feature, we conducted a field survey of the Jogasaki Coast, 8
9 km south of the area studied by Shishikura et al. (2023). We found four fossil calcareous assemblages at three sites on the Jogasaki Coast, and dated them to 13561470 CE using the C. Fossil assemblages with similar ages have been reported by Shishikura et al. (2023), but the elevation in this study is about 1 m higher. This difference may suggest a spatial variation in tectonic features in this area.
Tanaka, Kiriha; Ogata, Manabu; Tsukahara, Yuzuko; Nishiyama, Nariaki
no journal, ,
Electron spin resonance (ESR) dating of a quaternary sediment is a technology with the potential to directly determine the age of the last sedimentation. This method assumes that charges trapped in defects (trapped charges) in quartz in a sediment have been released by sunlight exposure (optically bleaching) during processes of erosion, transportation, and/or sedimentation, then trapped charges are accumulated by natural radiation during a process of burial. A sediment which has exposed to sunlight during a burial process must avoid being used for ESR dating, because its depositional age is underestimated. Thus, sediment under 
cm depth from an outcrop surface in strike direction, which is not exposed to sunlight, is conventionally used for ESR dating. However, the correct depth to be remove is not clearly demonstrated and unchecked each time. Therefore, it is crucial to reveal the effect of sunlight exposure on trapped charges detected by ESR measurements in a surface layer of an outcrop. In this study, silty aeolian loam and silt to fine marine sand samples were collected with poly vinyl chloride pipes with a diameter of 4 cm and a length of 35 cm from a terrace deposit located at the altitude of 30-33 m in Nanao-shi, Ishikawa prefecture. The loam and marine sand samples were cut into three and seven pieces, respectively. Quartz grains isolated by chemical processing were used for ESR measurements. For the loam sample, ESR intensity for the E
' center remained constant regardless of depth in the strike direction. Whereas ESR intensities for the Al and Ti center at depths of 20 and 30 cm were greater than that at a depth of 10 cm, respectively. For the marine sand sample, ESR intensities for all the trapped charges at depths of 3-14, and 33 cm were approximately equal, whereas the intensities were greater than those at depth of 20-30 cm.