In order to ascertain the correlation between (a) varieties/amounts of investigations, analyses/evaluation technique and (b) accuracy of the results (to what extent the deep geological environment are understood), geological models are constructed. For each of the Shobasama site and the study area for groundwater flow simulation (ca.4kmca.6km), two models are constructed. First model is based on the data from literature survey and other geoscientific researches. Second model is based on the data including the results of the Phase I-a.

In the first modeling, the granite is divided into only two parts because of the lack of information regarding fractured zones in the granite. These two refer to the weathered part and the remaining rock mass.

In the second modeling, newly extracted geological units in the Phase I-a are added to the geological models to improve them. These elements are, specifically, the Biotite granite, Felsic granite, "Upper fracture zone", "Moderately fracture zone" and "Fracture zone along the fault". These models are utilized for the construction of a hydrogeological model and the groundwater flow simulation, afterwards.

However, the improved geological models contain the uncertainty related to the shortage of information on geological structures in the northeastern part of the Shobasama site, the depth exceeding 1,000m and the fractures with a high inclination.