Particle motions near explosions in halite

Peak particle velocities and displacements were measured for tamped (coupled) and cavity (decoupled) explosions in halite. Recordings are illustrated of particle velocity versus time in the salt medium and of pressure versus time on the cavity wall. Peak particle velocities from tamped shots decrease as d−1.65 over distances equivalent to 40 to 800 feet for 1000 pounds of high explosive. Decoupling factors that were directly observed apply only to close-in stations. One method of extrapolating close-in data yields distant decoupling factors ranging from 40 to 100 for these particular experiments. Actual measurements (verbal communication from Herbst, 1960) of distant decoupling factors give larger numbers by a factor of 2. Extrapolation to nuclear explosions is not attempted here.