A Teledyne Benthos CHIRP SBP system (16 hull-mounted transducers) was used. The data were acquired by the SWANPRO software by Communication Technology, with direct interfacing to the DGPS, therefore actual positioning data have to be converted according to the offsets of Tab.3. The system setting (multiping mode) was: power full, length 20ms, trigger rate variyng from 0.5 to 0.687 s,gain 9dbm preamp gain ranging from 1.5 to 3 db. The data were recorded in the XTF format and converted also into the SEG-Y format for processing with ISMAR's SEISPRHO package [Gasperini and Stanghellini(2008)].