High-resolution marine magnetic surveys for searching underwater cultural resources

Abstract

Recently two marine magnetic surveys, combined with the use of a multi-beam sonar (Kongsberg Marittime EM 300 multibeam: 30 KHz frequency echosounder for hydrographic purposes; acoustic lobe composed of 128 beams able to cover a 150° sector) a side-scan sonar (Simrad MS 992 dual-frequency sidescan sonar with echo sounder transducers 150 Hz and 330 KHz) and a Remote Operated Vehicle (ROV – a mobile tools used in environments which are too dangerous for humans), were executed in two sites respectively in the Ligurian Sea and the Asinara Gulf. The aim of these investigations was to test modern instrumentations and set new working procedures for searching underwater cultural resources. The collected and processed magnetic data yielded very satisfactory results: we detected submerged and buried features of cultural interest at both sites, at depths of 40 m and 400 m respectively.