Marine Archaeology Survey by High-Resolution Sub-bottom Profilers

Abstract

Today’s focus on marine resources and environmental factors has supported a rapid development of technology for monitoring the coastal zones. Together with an increasing awareness of the historical and archaeological sites located under water as well as a growing understanding of the enormous research potential of the well-preserved submerged settlements and landscapes as an indispensable supplement to the investigations on land (Grøn & Skaarup 2004, 2006; Skaarup & Grøn 2004), it has been a logical step to attempt application of the technology to practical marine archaeological survey in shallow water (0.5-10m). Where side-scanners have become widely used in marine archaeological survey because of their ability to quickly create a high-resolution acoustic picture of the surface and texture of the sea-bottom, high-resolution sub- bottom profilers have not gained the same popularity in practical survey. It takes longer to cover an area with profiles with a reasonable resolution/ distance between them. Furthermore the sub-bottom profiles are significantly more difficult to interpret than the side-scan data. However, this should be weighed against the fact that a large part of the cultural heritage under water, and that is often the better preserved one, can be located only with high-resolution sub-bottom profilers because it is covered by re-deposited sediments. Furthermore the sub-bottom profilers can provide valuable detailed insights into the bottom’s small-scale geomorphology, which in relation to settlement investigations is added value (van Andel & Lianos 1984, Grøn 1990). 115