Abstract
This paper presents the contents of the compact vertical seismic prospecting (VSP) system and its application to in-situ measurement. A new method of rock property investigation by using this compact vertical seismic prospecting system is proposed. This investigation system consists of a vibration sensor and a super elastic alloy pipe to press the sensor against the borehole surface, an A/D converter, a computer and a trigger system. The vibration sensor setting on the spring of VSP probe is pressed to the borehole surface and measures the vibration due to a transmitted wave caused by the impact of the hammer on the tunnel wall. The distribution of the P wave velocity in rock can easily be measured along a borehole drilled for rockbolts.