The PARASOUND system (Krupp Atlas Elektronik GmbH, Bremen; details see Grant & Schreiber, 1990) is a high-resolution sediment echo sounder system able to penetrate the topmost 10 – 80 metres of the seafloor. Its advantage over standard 3.5 kHz systems is its utilization of the so-called parametric effect, which results in both higher vertical and spatial resolution. The system combines a narrow beam survey (NBS) system for the accurate determination of water depth with a sediment echo sounding system (Sub-Bottom Profiler) for sedimentological and echostratigraphic surveys. It is used to identify and evaluate lithological variations as well as sediment layers in deep-sea sediment sequences (Rostek et al, 1991).
During SO106 transit profiling the system was set to a frequency of 4 kHz, a pulse length of 0.25ms, and a registration window of 200 metres; the ship's speed was about 11 knots. During on-site work, additional frequency and pulse length tests were run using higher resolution windows (100, 50, and 20 metres). For 4, especially selected PARASOUND profiles in working areas 2 and 5 the speed was reduced to 7 knots to improve the quality of the DESO b/w analog printout.
Grant, J. A. and Schreiber, R. (1990): Modern swaths sounding and sub-bottom profiling technology for research applications: The Atlas HYDROSWEEP and PARASOUND systems; Mar. Geophys. Res. 12; 9-19
Rostek, F., Spiess, V. and Bleil, U. (1991): Parasound echosounding: Comparison of analogue and digital echosounder records and physical properties of sediments from the Equatorial South Atlantic; Marine Geology 99; 1-18; Elsevier Science Publishers B.V.; Amsterdam