A New Instrument for Making In-situ Acoustic and Geotechnical Measurements in Seafloor Sediments

摘要

The SAPPA (Sediment Acoustic and Physical Properties Apparatus) is a new instrument designed for the rapid acquisition of seafloor geophysical and geotechnical data. The pres- ent system can measure P-wave velocity and attenuation down to 1 m sub-bottom depth in sands and gravels, and the velocities of hori- zontally and vertically polarised shear waves at the surface. Preliminary tests show that s uffi- cient energy is produced to propagate P-waves at frequencies up to 10 kHz in water and S- waves at about 120 Hz through at least 1 m of wetsand