Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo; Sanga, Tomoji*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 18(1), p.3 - 23, 2011/06
Evaluation of the radionuclide migration toward the human environment associated with groundwater flow is an issue of importance in safety assessment of geological disposal. We constructed models depicting the influences of geomorphological evolution on long-term groundwater flow. This was done by reconstructing the processes of river deepening with historical simulation of the profiles of four rivers in the Boso Peninsula. The study resulted in the sum of erosion during the past 125,000 years which is the equivalent of one glacial to interglacial cycle. The profiles of four rivers during the last glacial age to the present were successfully reconstructed using similar parameters. It was found that the profiles were sculpted in accordance with the uplifting rates with very little influence of initial topography owing to the relatively soft and easily dissected characteristics of the geological units.
Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo; Sanga, Tomoji*
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 17(2), p.55 - 70, 2010/12
We conducted a study on key factors regarding changes of groundwater flow from the last glacial to the postglacial stages in the Horonobe. Specifically, geomorphological analysis was carried out using aerial photographs and a high resolution (10 m) DEM to obtain the distribution of the slopes that had been formed after the last glacial stage, and the erosion depth of those slopes was analyzed. The results are summarized as follows: (1) Although periglacial smooth slopes which expanded widely in Horonobe region over the last glacial stage were eroded by rainfall increase and steeper slopes had been formed in the postglacial stage, this postglacial erosion is not uniform and is strongly influenced by the geology. (2) The drainage density is low and less than 40% of periglacial smooth slopes have been eroded to the present in the Koetoi and Wakkanai Formations while it is high and 60% or more of those slopes have already been eroded in the Yuchi and Sarabetsu Formations.
Kimura, Hideo; Munakata, Masahiro; Hanatani, Ikuo; Sakai, Ryutaro; Namekawa, Maki; Matsuba, Hisashi
no journal, ,
Site selection of high-level radioactive waste geologic disposal on the detailed site investigation will be performed in the early of Heisei 20 years. In such case, the regulatory authority will be need to be concerned on the safety of geologic disposal, migration of radionuclides by groundwater flow from the disposal facility to human environment on the ground surface is very important key issue. We have been developed for the safety assessment methodologies of the regional groundwater flow on the geologic disposal site taking account of the naturally occurring events such as up-lift and erosion, variation of sea level.
Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo
no journal, ,
In order to evaluate the influence on a long-term groundwater flow system by geomorphic change, we carried out the numerical simulation of the changes in the longitudinal profile of river-bed for four rivers in a sedimentary rock area, and plotted the distribution map of the amount of gully erosion for 125,000 years. According to the results, the erosion estimates of the two rivers emptying into the inner bay ware different from the two rivers emptying into broad ocean. The estimates of the former group ware 50-300 m that varied widely from downstream site to upstream site. On the other hand, they ware 150-250 m ranging over the whole watershed in the latter group. Furthermore, the movement rates to the upstream of the erosional fronts formed with sea level decrease ware estimated 0.7-1.0 meter per year.
Munakata, Masahiro; Fuchiwaki, Hirotaka; Sakai, Ryutaro; Hanatani, Ikuo; Kimura, Hideo
no journal, ,
A long-term groundwater flow for reginal area of sedimentary rock was studied in order to develop the safety assessment code for groundwater flow. The area (40
50 km) consists of sandstone and mudstone with the monoclinal structure of their layers. The hydraulic data of the stratum was used from existing surveys and literatures. In addition, taking account of the geomorphic changes in long-term evaluation, uplift and erosion data in this area was adopted in the analysis. Analytical results show that the groundwater flow velocity after 100,000 years is increased by 5% in the 500 m depth of the center of the domain because of increasing hydraulic gradient caused by the geomorphic changes.
Hanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo
no journal, ,
In order that paleoclimatic changes might evaluate quantitatively the effect which it has on regional and long-term groundwater flow, the modern analogue technique was applied to the pollen data of 2 sites in northeast Japan, and it analyzed about past temperature and precipitation.
Kimura, Hideo; Munakata, Masahiro; Hanatani, Ikuo; Sakai, Ryutaro; Fuchiwaki, Hirotaka; Matsuba, Hisashi
no journal, ,
no abstracts in English
-ray detectionHanatani, Ikuo; Munakata, Masahiro; Kimura, Hideo; Sanga, Tomoji*
no journal, ,
In Japan Atomic Energy Agency, surveillance studies are currently underway with the aims of establishing the evaluation system of a groundwater flow for a regional scale over long periods and verifying a hydrologic groundwater flow model with survey data etc. As part of these studies, the lineament extraction and natural -ray detection were conducted in two granite distribution regions in order to estimate the distribution of fractures and the hydrogeological structure at the crystalline terrain in a mountain area deficient in the existing information such as a drilling investigation. This report describes the result of combinatorial utilization of lineament extraction and natural -ray detection.
