Ultrasound P-wave velocity and anisotropy of various rock types measured on spherical samples at confining pressures up to 400 MPa

Ultrasound P-wave velocity was measured on 152 spherical samples (5 cm in diameter) prepared from various rocks sampled at various localities on several continents. The method developed by Pros and Babuška (1968) was used. The measurements were executed at confining pressures in majority corresponding to 13 steps of a pressurization-depressurization cycle: 0.1, 10, 20, 50, 100, 200, 400, 200, 100, 50, 20, 10, 0.1 MPa. For each sample and for each pressure step the P-wave velocity was measured in 132 independent directions corresponding to a regular grid of 15 times 15 degrees. The density of each sample was calculated from the sample weight and volume measured during the sample preparation. The P-wave velocity and density data were acquired from late 1960' to late 2010' corresponding to the operational period of the related laboratory at the Institute of Geophysics CAS where all the physical data were acquired. The measured data are supplemented by calculated P-wave velocity anisotropy and by minimum, mean and maximum P-wave velocity per each sample and confining pressure level. Basic petrographic properties of the samples were described. The petrographic description given in the dataset is based either on our own observations of thin sections under the optical microscope or reported from the literature or the historical record on the samples preserved in the archive of the Institute of Geophysics CAS. The data were collected for various research purposes during the laboratory history as documented in the references mentioned for some of the samples in the dataset. The most prominent research topics the data has been and can further be used for are: 1) deciphering the relation between the rock microstructure and the rock elastic properties, 2) revealing the orientation of microporosity (mostly of cracks) and its compliance with confining pressure (depth) and 3) introduction of the directly measured elastic properties into geophysical modeling based on indirect (typically seismic) methods.