At the feasibility stage of a high-level radioactive waste facility in the eastern Paris Basin, the
French National Radioactive Waste Management Agency (Andra) has conducted innovative and
extensive characterization of the Callovo-Oxfordian argillaceous rock (Cox) and neighboring
Oxfordian and Dogger limestones; High resolution 3D seismic data were used to model the
distribution of mechanical and hydrogeological properties of the geological formations. Assessing the
reliability of the geophysical modelling is crucial for making decision on the design of the level
radioactive waste facility. Probabilistic modeling (geostatistics) has been successfully introduced in
the geophysical workflow to quantify uncertainty attached to processing and modeling outputs. The
result of such a hybrid geophysical- geostatistical processing is increased confidence in seismic
interpretation and modeling and reliable operational risk assessment.