Table T1 summarizes the cores that were selected for shore-based analysis. Nine of the cores were sampled from the whole core and were 5-6 cm long. (Normal cores acquired from just the working half are typically 2-2.5 cm long.) Vertical cores (z) were cut through the center of the whole core before splitting. The cross-core sample (x) was acquired in the direction of splitting. The into-core sample (y) was acquired perpendicular to the direction of splitting. After splitting into the working and archival halves, looking down on the working half with up away from you, +z is to the top of the core, +x is to the right, and +y is down. The x and y cores are mutually perpendicular and subhorizontal, but they are not oriented azimuthally because the drill core is not oriented. All but two of the minicores were classified as olivine gabbros. The other two cores were a troctolitic gabbro and a gabbronorite. The cores were stored in seawater immediately after sampling and were kept saturated until the velocity and attenuation measurements were made. They were then dried to get the dry bulk density and saturation porosity information.
The density, porosity, and compressional and shear wave velocity data, as acquired by New England Research, Inc. (Coyner, 1984), are presented in "Appendix A." The velocity measurements were made with the pulse-transmission technique. The confining pressure, Pc, was applied to the jacketed sample hydrostatically. The pore pressure, Pp, was kept at ~2 MPa. The velocities of compressional waves and of shear waves at two orthogonal polarizations through the core were made as confining pressure was increased from 10 to 200 MPa and then as pressure was decreased again. The difference in velocities at the same pressure measured during a pressure increase and during a pressure decrease is called hysteresis. Usually the velocities measured during the decrease are higher.