Seafloor Exploration Using the Multibeam Echo Sounder Technology: Some Examples.

Until the late 70's bathymetry data of the oceans were commonly acquired by
means of single beam echo sounders, along discontinue track lines with an uneven
spatial distribution. More recently, the MultiBeam Echo Sounder (MBES) technology
was made available to the academic research. These systems provide a full sea
floor search and a high resolution imaging of the seafloor. The MBES systems provide
depth values along a swath instead of a single point value by means of acoustic
pulses arrays. There are several MBES models characterizing by different technical
equipments in terms of frequencies, beam number and spacing. MBES systems are
used in archaeological and engineering fields, where high resolution data in small areas
are required, as well as in deep seafloor mapping aimed at large scale structures
detection. MBES may provide also grain size information besides bathymetric data,
recording the backscatter values that result from the interaction of acoustic pulses
with the seafloor. This tool is particularly important to characterize the distribution
of some features on the seafloor such as submarine landslides and other elements
that may play an important role in the assessment of the geological hazard along
the coasts. Actually some research groups are improving the backscatter analysis to
generate a semi-automatic seabed classification method. This contribution will provide
an overview of some recent examples studied within the framework of the CNR
research projects.