Tectonic Risk Forecasting Through Expert Elicitation for Geological Repositories: The TOPAZ Project

This paper describes the development of a probabilistic methodology for the evaluation of tectonic hazards to geological repositories in Japan. The approach is a development of NUMO’s ITM methodology, which produced probabilistic hazard maps for volcanism and rock deformation for periods up to about 100,000 years in a set of Case Studies that covered a large area of the country. To address potential regulatory requirements, the TOPAZ project has extended the ITM methodology to look into the period between 100,000 and 1 million years, where significant uncertainties begin to emerge about the tectonic framework within which quantitative forecasting can be made. Part of this methodology extension has been to adopt expert elicitation techniques to capture differing expert views as a means of addressing such uncertainties. This paper briefly outlines progress in this development work to date.