Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Tanikawa, Shinichi; Sanga, Tomoji*; Yasue, Kenichi
Chikei, 37(2), p.189 - 207, 2016/04
JP, 2009-239446
Patent publication (In Japanese)
Existing 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, Yuichi*; Sugai, Toshihiko*; Yasue, Kenichi; Kokubu, Yoko
Chikei, 32(2), p.201 - 206, 2011/04
Analyses data of 24 shallow cores obtained from the Nobi plain, on the footwall side of the Yoro fault, suggest river channel change to west and temporal sea-level rise. The cores are represented by delta system and overlying fluvial system. Stacking patterns of the sedimentary units in the cross sections from the northern plain and 
C ages indicate the possibility that river channel change to the west has been occurred at ca. 2300 cal BP. High electrical conductivity, and brackish-marine diatom species identified in back swamp deposits in the cross section from the southern delta plain suggest temporal relative sea-level rise occurred at 1600 to 2700 cal BP. There is synchronism of the above-mentioned channel change and temporal sea-level rise events. Two possibility is considered as cause of these events; one is tectonic tilting and coseismic subsidence by the faulting at the Yoro fault, another is transgression at the Middle Ages.
Sanga, Tomoji*; Yasue, Kenichi
Chikei, 29(1), p.27 - 49, 2008/01
We will first show in this paper that the longitudinal river profile can be estimated by model simulation. Then the results of application of similar algorithm to an actual river profile will be laid out. Also the results of application to a number of river profiles will be reported. Also it will be shown that the erosion process varies with rivers, particularly the location of the erosional front varied considerably. This difference of erosional process can be explained by the distribution of geologic units, and thus the past changes of topographic features can be reproduced by this simulation.
; *
Nicchu (Unnan) Chikeigaku Godo Gakujutsu Taikai (JAPAN-CHINA (YUNNAN) GEOMORPHOLOGI, 0 Pages, 2002/00
None
