Reverse vertical seismic profiling using the research gallery in granite

Yamada, Nobuto; Matsuoka, Toshiyuki; Ishigaki, Koichi*; Kanazawa, Yohei*; Tokuyasu, Shingo*; Nakahara, Junichi*

Evaluation on the geological discontinuity is one of the important issues for safety assessment of high-level radioactive waste disposal. A Reverse Vertical Seismic Profiling (RVSP) investigation using blasting vibration for excavation of the research gallery and survey lines placed in the -300m research galleries of the Mizunami Underground Research Laboratory has been carried out to obtain three-dimensional information on the geological discontinuity such as faults and fracture zones in granite during the research galleries excavation works. In this study, results of RVSP are compared with existing information such as sonic logging to estimate spatial distribution of faults and fracture zones, and the applicability of this method to estimate geological structure in the granite is discussed.