Compressional‐wave velocities in basalts from the Juan de Fuca Ridge

Compressional-wave velocities are reported to pressures of 10 kb for three samples of tholeiitic basalt dredged from the Juan de Fuca ridge. Average velocities for air-dried samples range from 3.90 km/sec at 0.2 kb to 6.44 km/sec at 10 kb. Low-pressure velocities are increased by as much as 25% with water saturation, whereas velocities above 3 kb are only slightly increased. Compressional-wave velocities for the basalts are clearly lower than seismic refraction velocities for lower oceanic crustal rocks near the Juan de Fuca ridge. The water-saturated basalt velocities are, however, within the range of reported velocities for layer 2 of the oceanic crust.