Recent geophysical exploration of the ocean floor

Seismic Velocities of Leg 37 Rocks and Their Geophysical Implications

“…AND COMPOSITION Early studies of oceanic crustal seismic structure by Hill (1957) and a summary of numerous refraction profiles by Raitt (1963) proposed a three-layer model for the oceanic crust which is still generally accepted today. This model consists of a 0.5 to 1 km layer of sediments overlying a second layer with a relatively well defined thickness (1.0 to 2.5 km) and a highly variable compressional wave velocity (3.5 to 6.5 km/sec).…”

Are Cells Viable at Gigapascal Pressures?

“…Because of the geothermal gradient, the temperature in a subduction zone (12) at depths where the pressure is 1 GPa far exceeds the permissible limit for life.…”

Saudi Arabian seismic deep-refraction profiles; final project report

“…Girdler (1969) interpreted the high-velocity basement in the axial trough as oceanic crust and the 29 lower-velocity basement on the shelves as continental material. For oceanic basins, the arithmetic mean seismic P-wave velocity of layer two, the upper layer of oceanic crust, is only about 5.1 km/s (Hill, 1957, and Raitt, 1963, cited in Le Pichon and others, 1973, with a standard deviation of 0.6 km/s; if velocities for oceanic crust of Tertiary age are not greatly different from the arithmetic mean figures, then the lower-velocity basement reported by Girdler (1969) could be oceanic or continental.…”