Geophysical seafloor exploration with a towed array in shallow water

S.M. Jesus
UCEH - Universidade do Algarve
PT-8000 Faro, Portugal
DSEA - Universita di Pisa
Pisa, Italia.

Comments: download pdf file .
Ref.: in 2nd MAST Days and EUROMAR Market Conference (ISBN 92-827-5012-4), p.1147-1160, Sorrento, Italy, 1995.

Abstract: The quantitative measurement or estimation of the geophysical properties of the seafloor upper sedimentary strata is a requirement in several marine applications, from geotechnical engineering to underwater acoustics. Traditional methods employ in-situ instrumentation (cone penetrometers, coring, etc.) and are able to probe the seafloor at selected points. This project aims at exploring the feasibility of seafloor model identification by acoustic means. In particular, the project has considered the use of an acoustic system, in which a ship tows both an acoustic source and an horizontal array of receivers. From the acoustic field measured at the receiving array, the seafloor parameters are estimated by suitable inversion algorithms. The project focused in particular on the use of such a system in shallow waters, and considered the advantages and limitations of the method from the  point of view of system requirementes, signal processing and inversion strategies. Sensitivity studies show that it is indeed possible to recover the seafloor parameters in shallow water with a moderate aperture towed array, and experimental results are shown to demonstrate the feasibility of the concept. Possible improvements and further lines of research are also discussed.

ACKNOWLEDGMENT: this work was partially supported by the EU project MAS2-CT920022.