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Pachri, H.*; Mitani, Yasuhiro*; Ikemi, Hiroaki*; Nakanishi, Ryunosuke*; Kokubu, Yoko
Journal of Geological Resource and Engineering, 3(4), p.163 - 172, 2015/09
Recently, the contributions of slope failures have been difficult to quantify over the time scales of the sediment concentrations in Sangun catchment area, Fukuoka Prefecture. This paper describes how cosmogenic nuclide methods have provided information about the geomorphic process by utilizing Be. The Be/Be ratios were measured by AMS. We assume that the cosmogenic nuclide concentrations stored in the sediment of a river can increase or decrease, depending on the amount of mixing of sediments during transport through the fluvial system. As results, the Be concentrations have been calculated to determine the short term sediment mixing rate in the catchment area. Therefore, the relationship between the morphometrics of the drainage basin, the sediment concentration by Be analysis and the contribution of landslides to landscape changes over timescales of several years have been investigated in Sangun catchment area.
Ezaki, Tetsuro*; Jinno, Kenji*; Mitani, Yasuhiro*; ; Uchida, Masahiro; Yoshino, Naoto
JNC TY8400 2001-005, 93 Pages, 2001/06
no abstracts in English
Ezaki, Tetsuro*; Jinno, Kenji*; Mitani, Yasuhiro*; ; Uchida, Masahiro;
JNC TY8400 2000-004, 94 Pages, 2000/03
no abstracts in English
Ikemi, Hiroaki*; Pachri, H.*; Kokubu, Yoko; Mitani, Yasuhiro*; Kuroki, Takahito*
no journal, ,
One of issues in the comprehensive river-sediment management is to develop how to estimate a sediment production from a mountainous stream. In this study, beryllium isotopes of quartz extracted from sediment samples have been analyzed by JAEA-AMS-TONO to clarify a sediment dynamics in mountain streams. The sediment samples have been collected at four riverbeds and one hillslope in two different sub-catchments (A and B) of a Mesozoic granitic block located in the Umi-kawa river basin, Fukuoka. The sample of the catchment B shows a little bit higher value in Be-content than those of catchment A. This result indicates that the river sediment in the catchment B includes quartz grains that have been exposed on a ground surface for a long time compared with the catchment A. It is also possible that the river sediment in the catchments A contains more landslide materials because the landslide materials, which have come from a deeper part, might have a lower value in Be-content.