Compressional Wave Velocities in Basic Rocks

Abstract

Compressional wave velocities determined by measurement of travel times of pulses at pressures to 10 kilobars are given for specimens of basalt. Variations of velocity with propagation direction are related to feldspar orientation and inhomogeneity in alteration of the specimens. Velocity differences reported for diabase, gabbro, eclogite, and basalt can be explained in terms of variation of density and mean atomic weight . The basalts have the lowest compressional wave velocities of basic rocks. The low velocities are a consequence of slight alteration, high mean atomic weight, and relatively low density.