Study on geological environment model using geostatistics method (Joint research)

Honda, Makoto*; Sakurai, Hideyuki*; Suzuki, Makoto*; Iwasa, Kengo*; Matsui, Hiroya 

The purpose of this study is to develop a geostatistical procedure for modeling on geological environments and to evaluate quantitative relationship between amount of geological information and reliability of the models using data sets obtained in surface-based investigation phase (Phase 1) of the Horonobe Underground Research Laboratory Project. This study is a joint research with Shimizu Corporation carried out in four years from FY2003 to FY2006. In the first three years, by using the data sets obtained by the geological investigations in each FY, three dimensional models of the resistivity, the chemical composition of groundwater and the hydraulic conductivity were built and undated by the geostatistical method developed in this study. The relationship between the amount of information and the reliability of the models were demonstrated as well through comparisons of the models at each step which corresponds to the investigation stage in each FY. In FY2006, as a summary of this study in the final FY, to confirm the validity of the present method, the above three models were compared with models built by a conventional method. Relationship between the procedure of geological survey and the reliability of the models were also studied by newly computing three sets of models based on fictitious investigation plans, their procedures are different form the actual one, and comparing these four models.