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Sueoka, Shigeru; Tagami, Takahiro*
no journal, ,
We compiled themochronometric data along the Niigata-Kobe Tectonic Zone, a high-strain rate zone located in Japan, and its vicinity areas to illustrate its vertical deformation over geological time scale. We discuss uplift/denudation histories in the five subareas: the Pacific coast region of the NE Japan, the Japanese Sea coast region of the NE Japan, the northern Japanese Alps region, the Japanese Sea coast region of the western Chubu district, and the Japanese Sea coast region of the Kinki district.
Mizuno, Takashi; Matsuoka, Toshiyuki; Ishii, Eiichi
no journal, ,
This study is aimed to extract important factors for increasing the reliability of GEMs based on cross-reference of geological, rock-mechanical, hydraulic and hydrochemical models of Horonobe area northern Hokkaido, Japan. As the result, distribution and evolution processes of geological structures which define the high-permeable area and hydrochemical distribution, and rock mechanical property which control the variation of permeability in rock matrix are extracted as important factors. In future, we will conduct FEP analysis and PID construction for more detail study.
Takeuchi, Ryuji; Saegusa, Hiromitsu; Onoe, Hironori; Beppu, Shinji
no journal, ,
Saegusa, Hiromitsu; Takeuchi, Ryuji; Onoe, Hironori; Beppu, Shinji
no journal, ,
Ishii, Yasuo; Sasaki, Yoshito; Watanabe, Takayoshi; Oyama, Takuya; Abe, Hironobu; Niizato, Tadafumi; Sato, Haruo
no journal, ,
As part of the project entitled "Long-Term Assessment of Transport of Radioactive Contaminant in the Environment of Fukushima" (F-TRACE project), JAEA has researched since November 2012 to predict the transport behavior of radioactive caesium, which now Cs-134 and Cs137 are the main radiological contribution, from contaminated mountain forests to estuary and coast through dam, pond, river etc. based on their investigated data survey data in the Fukushima prefecture. In this study, we report characterization and radio assay of the surface run-off substances obtained (or collected) at the forest observation plots in the Ogi district of Kawauchi-mura and the Yamakiya district of Kawamata-machi, and at the soil-saving dam in the Ogaki district of Namie-machi, Fukishima prefecture, Japan. The air dose rates measured at 1m in height were about 2-3 
Sv/h at the forest observation plots in Ogi and Yamakiya, and about 10 Sv/h at the soil-saving dam in Ogaki. Both Cs-134 and Cs-137 were detected from soil samples taken in these areas, and their concentrations were high particularly in the muddy substances (silts and clay). This tendency was similar to the sediment samples taken in dam and river areas in Fukushima.
Umeki, Hiroyuki; McKinley, I. G.*; Russell, A.*; Hardie, S. M. L.*
no journal, ,
Takeuchi, Shinji*; Saegusa, Hiromitsu; Takeuchi, Ryuji
no journal, ,
Inagaki, Daisuke; Ijiri, Yuji*; Nago, Makito*; Hatsuyama, Yoshihiro*; Sato, Masaru*; Kunimaru, Takanori*
no journal, ,
no abstracts in English
Niizato, Tadafumi; Ishii, Yasuo; Abe, Hironobu; Watanabe, Takayoshi; Sasaki, Yoshito
no journal, ,
Understanding the environmental dynamics of the radiocaesium (particularly Cs-134 and 137) released from the Fukushima Daiichi Nuclear Power Plant provides the firm foundation for a remediation of the Fukushima environment because it is the main radionuclide to radiological dose within the contaminated area. One of the main sources of radiocaesium under the current situation is a mountain forest, where the decontamination work has not been carried out as yet. Therefore, transport process, flux and chemical form of the radiocaesium flowing from the mountain forest are crucial issues for an evaluation of a radiation exposure, taking into a dynamics behavior of radiocaesium from the highest contaminated mountain forests down through the river to eventual deposition in the sea. This paper discusses the predominant process of the radiocaesium transport in the mountainous region, Fukushima, Japan.
Sato, Haruo; Niizato, Tadafumi; Tanaka, Shingo*; Abe, Hironobu; Aoki, Kazuhiro
no journal, ,
This work was conducted as one of the researches relating to distribution maps of radiation dose rate, etc. which the government has promoted as one of the counter-measures to the Fukushima Dai-ichi Nuclear Power Plant (1F-NPP) accident in March 2011, and the 1st and 2nd investigations on the depth distribution of radionuclides (RNs) were conducted in June 2011 after about 3 months and in February and March 2012 after about 1 year from the 1F-NPP accident, respectively. The authors investigated at 11 locations in Nihonmatsu-city, Kawamata-town and Namie-town in the 1st investigation and obtained the distribution coefficients (Kd) of Cs-137 and I-131 onto soil and the apparent diffusion coefficients of RNs. The 2nd investigation was also conducted at the same locations basically. Sorption-desorption experiments of Cs-137 and I-131, CEC and AEC measurements and mineralogical analyses by XRD were conducted for 3 types of soils (sandy, clayey, organic) and those elutriated components (clay, silt, sand). Radiocaesium (Cs-134 and Cs-137) and Ag-110m were detected at all locations investigated and only at locations where radiation dose rate is high, respectively. Radiocaesium more than 95% and 99% of the inventory distributed within 5cm and 10cm deep in soil in the surface layer (mainly sandy soil is the support layer), respectively, and little evolution in the penetration profile was found. Whilst, radiocaesium more than 95% and 99% of the inventory distributed within 16cm and 20 cm deep in organic soil and in soil at locations where are supposed to have been used as farmland, respectively, and penetration profile tended to extend to deeper parts in soil that organic and clayey soils are the support layer, particularly in organic soil. The Kd-values of Cs-137 onto organic soil and its elutriated components were also lower than that onto other soils. This is consistent with trend of penetration profile.