The Tsukiyoshi fault intersects granites at depth in the Shobasama Site. Taking advantage of this geological feature and the results of the previous investigations, techniques for systematic investigations and modelling of the geological environment, especially for the estimation of hydrology around fault zone, will be developed and advanced.

In particular, geological, hydrological and hydrochemical investigations of the geological environment, including identification of permeable fractures, are carried out for hydrogeological modeling and groundwater flow simulation. After identification and characterization of permeable fractures, hydrological and hydrochemical studies with surface-based investigation and in deep boreholes, and hydrogeological modeling and groundwater flow simulation will be carried out.

Thereafter, the monitoring of groundwater flow in the deep boreholes will be further carried out.