Dispersion of seismic waves near a small explosion

Abstract

The characteristics of the ground vibrations caused by the detonation of small dynamite charges were studied at distances from ten to 3070 ft from the point of detonation. The motion which was observed could be separated into several types on the basis of velocity and particle motion paths. The major part of the recorded motion following the arrival of body waves exhibited strong dispersion. A comparison of this dispersion with that theoretically predicted for Rayleigh waves by Love, Sezawa, and others, showed that these motions are probably Rayleigh waves of the first and second types. The complex particle motion orbits observed near the shot point are probably a result of the overlap of these two normal modes of surface wave propagation.