Laboratory simulation of impact cratering with high explosives

Impact and explosion craters have been formed at the same scale in the laboratory. Impact craters were produced with cylinders of aluminum of mass 0.4350 gram that were impacted with velocity of 2.0 km/sec and kinetic energy of 8.7×109 ergs against quartz-sand targets. Explosion craters were produced by detonating 0.150-gram charges of PETN high explosive yielding a chemical energy of 8.7×109 ergs at various depths beneath the target surface. Crater size and shape, ejecta-plume growth, and subsurface deformation have been determined. Measurements of cratering effects show that impact-crater formation can be simulated by detonation of the explosive placed at a depth of burst of 6.3 mm±2 mm (λ = 0.26±0.10 for cube-root scaling). Caution should be used in applying these results to estimate kinetic energy of formation of large impact craters because knowledge of projectile velocity might be needed in addition to knowledge of crater size to estimate kinetic energy of formation of the crater using an explosion-crater analog.