In-situ evaluation of high accuracy elastic wave measurement system with pseudo random wave

Ishiyama, Koji*; Yoshino, Osamu*; Hikima, Ryoichi*; Matsui, Hiroya ; Ozaki, Yusuke  ; Takeuchi, Ryuji  ; Sakakibara, Junichi*; Sanoki, Satoru*; Hayashi, Kunihiko*

In this study, we evaluate the high accurate elastic wave measurement system at the 500m stage in Mizunami underground research laboratory. We used the sine and pseudo random wave between 0.5 kHz and 20 kHz as source signals and received them by 6 receivers. We observed that the elastic wave became low speed and high attenuation around the zone where the rock classification was lower than surroundings. From this result, we could capture the damaged zone by elastic wave. For the capability of deeper exploration, we need to improve the transmission system.