Development of 3-D lithostratigraphic and confidence models at Yucca Mountain, Nevada

Computerized three-dimensional geologic models of potential high-level nuclear waste repositories such as Yucca Moutain, Nevada, are important for visualizing the complex interplay of (1) thickness and facies variations in lithostratigraphic units and (2) the disruption of these units by faults. The concept of a 'model of confidence' in the lithostratigraphic model is introduced to show where data are located versus regions where interpolations are included. Models of confidence can be based on (1) expert judgment, (2) geostatistical analysis, or (3) a simplified combination of these two methods. Linking of lithostratigraphic models and models of confidence provide guidelines for future characterization and modeling activities, as well as for design and construction of the Exploratory Studies Facility.