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Balkanska, E.*; Georgiev, S.*; Kounov, A.*; Peytcheva, I.*; 田上 高広*; 末岡 茂
no journal, ,
ブルガリア・Sredna Gora帯のVariscan期の基盤における冷却・削剥史の推定を目的として、アパタイトFT解析を実施した。標高の異なる4試料からは年代と標高に正の相関がみられ、見掛けの削剥速度は0.45mm/yrと推定された。FTデータに基づいた熱履歴逆解析の結果では、45-35Ma頃に中程度の冷却が認められた。この冷却は、造山運動後の削剥と、始新世のThrace盆地形成に伴う引張に関連している可能性がある。
Cs emitted from Fukushima Daiichi Nuclear Power Plant, and application of MIPs' results for usage in an emergency山澤 弘実*; 佐藤 陽祐*; 関山 剛*; 梶野 瑞王*; Fang, S.*; Qu
rel, A.*; Qulo, D.*; 近藤 裕昭*; 寺田 宏明; 門脇 正尚; et al.
no journal, ,
2011年3月に福島第一原子力発電所(FDNPP)から放出されたCsを対象とした大気拡散モデルの第3回相互比較(MIP)が実施された。前回の第2回MIPと同様、参加した全9モデルで共通の放出源情報と気象データが利用されたが、FDNPP近傍で測定された大気中Csの挙動の理解のため水平格子解像度は前回の3kmより高い1kmとされた。その結果、第2回MIP同様にほとんどの観測された高い大気中Cs濃度が良好に再現され、性能の高い数モデルにより性能の低いモデルの影響が打ち消されるマルチモデルアンサンブルの利点が示された。また、高い格子解像度により気象場が改善した結果、FDNPP近傍でのCsの挙動が第2回MIPより合理的に再現された。さらにMIPの結果の解析により大気拡散シミュレーション結果の緊急時における有用性について調べたところ、各モデルのCs濃度計算値の絶対値の差異がファクター3からファクター6である場合もマルチモデルアンサンブルによる観測されたプルームの見逃しはわずか3%であり、有効なマルチモデルアンサンブルには6から8モデルが必要であることが示された。
Di Palma, A.*; Adamo, P.*; 土肥 輝美; 藤原 健壮; 萩原 大樹; 飯島 和毅
no journal, ,
Nine years after the FDNPP accident, in line with the strong efforts to devise ever more effective methods to monitor airborne radioactive dusts, in the present study we proposed for the first time the use of mosses transplanted in bags as biointerceptors of 
Cs and Cs in the evacuated zone of the Fukushima territory and according to a standardised protocol. The work aimed to investigate the ability of the moss transplants to accumulate radiocaesium (RCs) and therefore to act as RCs biointerceptors. To this purpose, the activity concentrations of RCs were measured in moss bags filled with 3 widely studied moss species (Sphagnum palustre, Hypnum cupressiforme, Hypnum plumaeforme) and exposed for 3, 6 and 9 weeks at 5 residential sites within Fukushima area. The moss bags accumulated Cs in all exposure sites and periods, with S. palustre acting as the most performant moss species.
Cs wash-off from bareland in Fukushima五十嵐 康記*; 恩田 裕一*; 脇山 義史*; 吉村 和也; 加藤 弘亮*; 小塚 翔平*; 馬目 凌*
no journal, ,
The impact of freeze-thaw processes and subsequent runoff affecting the Cs flux and concentration in sediment discharge were revealed in bareland erosion plot following the Fukushima nuclear power plant accident by detailed monitoring and laser scanner measurement on the soil surface. We found that surface topographic changes due to the frost-heaving during the winter-spring period, and rill formation during the summer. We also found the evident seasonal changes in Cs concentration; high during the early spring and gradually decreased thereafter, then surface runoff from the plot frequently occurred during spring and autumn when rainfall was high and reached a maximum in summer. From these results, the higher Cs concentration in spring was caused by a mixture of unstable surface sediment following freeze- thaw processes and then transported in the early spring, but erosion amount is not significant because of the less rainfall event. The sediment with a lower Cs concentration, which was supplied from the rill erosion and its expansion, was wash-offed during the summer, contributing most of the flux from erosion in bareland in Fukushima region.
恩田 裕一*; 谷口 圭輔*; 吉村 和也; 脇山 義史*
no journal, ,
The Fukushima Daiichi Nuclear Power Plant (FDNPP) accident released the largest quantity of radiocaesium into the terrestrial environment since the Chernobyl nuclear accident. The surrounding land received 2.7 PBq of radiocaesium to forests, agricultural lands, grasslands, and urban areas, from which the radionuclides migrated through soil and waterways. In this presentation, the deposition and distribution of radionuclides, especially radiocaesium, in the terrestrial environment as a result of the FDNPP accident are discussed based on the past 10 years' intensive dataset. Anthropogenic activities such as rice and vegetable cultivation and residential activities in the upstream area have led to a rapid decline in the activity concertation of Cs of suspended sediment (SS) transport in the river network, and these declines directly control the dissolved Cs concentration in the river water. We outline the environmental and anthropogenic factors that in uenced the subsequent transport and impacts of radionuclides through the environment. The environmental aftermath of the accident at Fukushima is compared to Chernobyl, and the relatively rapid remediation of the Fukushima region relative to the region surrounding Chernobyl will be explained.
田中 桐葉*; 長濱 裕幸*; 武藤 潤*; 岡 壽崇; 矢部 康男*
no journal, ,
地震に先行する電磁気現象の観測は地震予測に利用できると考えられているが、電磁気現象の発現メカニズムの詳細は不明である。本研究では、電子スピン共鳴法を用いて電子・正孔捕獲中心の濃度を調べたところ、石英砂中の破砕が電磁気現象における表面帯電を引き起こす可能性があることがわかった。