Synthetic 3D Recording of a Shipwreck Embedded in Seafloor Sediments: Distinguishing Internal Details

Abstract

3D recording of shipwrecks completely buried in seafloor sediments has great potential as an important aspect of maritime archaeological surveys and management. Buried shipwrecks have been recorded directly with seismic 3D Chirp sub-bottom profilers on an experimental basis. This method is, however, expensive, time-consuming and complicated. This article outlines the application of a faster, cheaper, and less complicated method of synthetic 3D recording, which is also less sensitive to weather conditions. It involves the acquisition of a larger number of seismic 2D high-resolution sub-bottom profiles in a dense grid that does not need to be regular. The method is based on the results of survey work conducted in the Akko Harbour area, on the Carmel coast of Israel, which shows that the shape of the hull of a shipwreck can be precisely determined, and that the sedimentary units bounding it can be outlined and interpreted. Based on an interpretation of the shape of the hull, the depth of the structure was measured, and a 3D image of the shipwreck was subsequently generated. Samples of the sub-seafloor were obtained across the area, and the sample located within the area of the mapped shipwreck was found to contain wood fragments and a piece of rope. This article demonstrates that 2D surveying is a viable and cost-effective alternative to 3D surveying that is able to produce good results.