Assessment of Heterogeneous Geological Environment Using Geostatistical Techniques; A Technical Report

Toida, Masaru*; Suyama, Yasuhiro*; Shiogama, Yukihiro*; Atsumi, Hiroyuki*; Abe, Yasunori*; Furuichi, Mitsuaki*

"Geoscientific research" at Tono are developing site investigation and assessment techniques in geological environment. One of their important themes is to establish rational methodology to reduce uncertainties associated with the understanding of geological environment, which often exhibits significant heterogeneity. Purpose of this study is to identify and evaluate uncertainties associated with the understanding of geological environment. Because it is useful to guide designing effective site investigation techniques to reduce the uncertainty. For this, a methodology of the uncertainty analysis concerning the heterogeneous geological environment has been developed. In this report the methodology has also been tested through an exercise attempted in Tono area to demonstrate its applicability. This report summarizes as follows: 1)The exercise shows that the methodology considered 'variability' and 'ignorance' can demonstrate its applicability at three-dimensional case. 2)The exercise shows that the methodology can identity and evaluate uncertainties concerning ground water flow associated with performance assessment. 3)Based on sensitivity analysis, it is possible for the methodology to support designs of the following stage investigations to reduce the uncertainties efficiently.