Experimental measurements of the phase and group velocities of body waves in a transversely isotropic medium

Abstract

In this study, we perform an experimental result for measurements of the body wave phase and group velocities in transversely isotropic media (TIM) by through-transmission technique. After comparing the experimental and theoretical first arrival times of the waves, a difference between the phase velocity and group velocity is observed. When the ratio between propagation distance ( d) of the wave and the diameter ( D) of transducer is 2.4 for measuring phase velocity and the point probes configuration for measuring group velocity, the accuracy in velocity estimation can reach the limit of system's resolution. However if d/ D is 7.8, the wave will propagate with an intermediate velocity between the phase and group velocities. The rapid change of the wave velocity and waveform for qSV-wave propagation with the group velocity has been observed at the propagation direction near the cusps. Therefore, in order to reduce the error in group velocity estimation of qSV-waves, the optimum directions are suggested at 20 and 60°.