Seismic Prospecting in Shobu Landslide Area, Tokushima Prefecture

Abstract

Interpretations in seismic-refraction prospecting applied to a landslide area in Shikoku are described in detail. It is important to distinguish inherent velocities, which are consistent in an area concerned, from apparent ones before constructing a working model for interpretation. Delay-time method reveals to be useful in a case where the shot marker happens to be unreliable. Fan-shooting technique is employed for surveying deeper substratum by means of shorter spreads. A small scale low-velocity zone is detected by ordinary profile shooting as well as by fan shooting.