Geo-Descriptive Modeling of Water Conducting Features Characterized in Sedimentary Formations in Horonobe Area of Japan
- PDF / 484,988 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 101 Downloads / 147 Views
1265-AA06-04
Geo-Descriptive Modeling of Water Conducting Features Characterized in Sedimentary Formations in Horonobe Area of Japan Koichiro Hatanaka1, Doo-Hyun Lim2, Eiichi Ishii1 1 Horonobe Underground Research Center, Japan Atomic Energy Agency, Hokushin 432-2, Horonobe, Hokkaido 098-3224, Japan 2 Golder Associates, 18300 NE Union Hill Road, Redmond, WA98052, U.S.A. ABSTRACT A three-dimensional (3-D) discrete fracture network (DFN) geo-descriptive model is developed for water conducting features (WCFs) in the sedimentary formations of Horonobe underground research laboratory (URL) in Japan. Fracturing and faulting system in/around the URL area, which is the main investigation area of the Horonobe URL project, is characterized by taking into account borehole geophysical logging data, regional geologic/structural data, and fracture/fault data (orientation, intensity, size) obtained from the surface-based investigations. Volumetric fracture intensity potential is estimated by the correlation and the multi-linear regression analysis of observed data, and is used as one of controls for 3-D DFN model. A regional scale 3-D geo-descriptive DFN model is constructed based on the analyzed fracturing system identified for the WCFs. The current 3-D geo-descriptive model could be utilized explicitly to derive performance assessment (PA) parameters for the hypothetical repository of the high-level radioactive wastes in Japan, and to assist optimization of the safe repository design. INTRODUCTION Japan Atomic Energy Agency (JAEA) has been carrying out the Horonobe URL project to establish/demonstrate methodologies for site characterization, repository design, and performance assessment in the geological environment consisting of sedimentary formations distributed in the Horonobe Town area, Hokkaido, Japan. In the Horonobe Town area, Neogene to Quaternary sedimentary sequences are underlain by igneous and Palaeogene to Cretaceous sedimentary basement. There are some major faults in the area of interest, such as the Omagari Fault and the Horonobe Fault. The Wakkanai and Koetoi Formations, which are Neogene argillaceous sedimentary formations, have been selected as the hosts for the URL construction and the investigations. Saline groundwater is found to be distributed in the deeper part of the geological formations. In the Horonobe URL project, the surface-based investigations of Phase I started in March 2001 and completed in 2005, and the obtained Phase 1 data has been utilized for this study. In the geoscientific investigations of the URL project, a geo-synthesis methodology has been applied to characterize the relevant properties and processes in the geological environment [1] with required data collected & synthesized since initiation of the URL project. By synthesizing the multidisciplinary data, the Omagri Fault, which is one of main focuses for the investigations and is running over the URL area, was identified as a major WCF, and the 3-D geological structure and hydro-geological properties were estimated. In addition, min
Data Loading...
