ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02

2aUW6. Acoustical properties of undisturbed sands from the West Florida sand sheet.

Horst G. Brandes

Armand J. Silva

Dept. of Ocean Eng., Univ. of Rhode Island, Narragansett, RI 02882

Eight undisturbed large-diameter (10.1-cm) gravity cores, ranging in length from 13.5 to 50.5 cm, were collected at the CBBL-SRP study site southeast of Panama City, FL. The recovered sediments varied from coarse sand and shell fragments near the surface to fine/medium sand at depth. The Multi Sensor Core Logger was used to measure compressional wave velocity, density, and attenuation as a function of depth in each of the unsplit cores in two mutually perpendicular directions. Two spring-loaded compressional wave transducers operating at 500 kHz, mounted on the outside of the liner, were used to measure velocity and attenuation, and a Cs-137 gamma ray source with scintillation counter were used to measure bulk density. In the longest of the cores, PC-GC-623, compressional wave velocity varied between 1700 and 1730 m/s in the upper 10 cm and between 1650 and 1700 m/s below that depth. Attenuation decreased slightly with depth, with most values falling between 0.3 and 0.5 dB/kHz/m (with reference to core liner filled with water). Density was relatively depth-independent and ranged between 1.8 and 1.9 g/cm[sup 3].