Crosshole seismology and seismic imaging in crystalline rocks

Abstract

A borehole‐to‐borehole audiofrequency seismic system using piezoelectric transducers as active elements has been developed and used to investigate crystalline rocks in Canada. High‐quality seismograms have been recorded for transmitter‐receiver distances of up to 230 meters. It has been found that both travel times and signal amplitudes provide diagnostic information about rock quality. Two‐dimensional images of seismic velocity and transparency distributions between two boreholes, derived from observed arrival times and amplitudes by simple back‐projection tomography, reflect lithology and geological structure. The results indicate the potential usefulness of crosshole seismic imaging as a tool for rock mass characterization.