Hydrogeological invesitigation in Mizunami Underground Research Laboratory Project; Multiple lines of evidence for hydrogeological characterization in Mizunami Underground Research Laboratory Project

Takeuchi, Ryuji  ; Saegusa, Hiromitsu; Oyama, Takuya ; Matsuoka, Toshiyuki; Takeuchi, Shinji

The Mizunami Underground Research Laboratory (MIU) is now under construction by Japan Atomic Energy Agency in the Cretaceous Toki granite in the Tono area of central Japan. The project is implemented in three overlapping phases: Surface-based Investigation (Phase I), Construction (Phase II) and Operation (Phase III), with a total duration of 20 years. Phase II of the MIU project is now carried out. The long-term monitoring, which are hydro-pressure, surface tilt and self-potential measurement, are carried out in/around the MIU construction site. This paper shows the possible application of using long-term monitoring data for characterizing the hydrogeological structures of the site.