Research Article Chirping for Large-Scale Maritime Archaeological Survey: A Strategy Developed from a Practical Experience-Based Approach Ole Grøn 1 and Lars Ole Boldreel 2 1 Strandingsmuseet St. George, Vesterhavsgade 1E, orsminde, 6990 Ulborg, Denmark 2 Department of Geosciences and Natural Resource Management, Section of Geology, University of Copenhagen, Øster Voldgade 10, 1350 Copenhagen K, Denmark Correspondence should be addressed to Ole Grøn; olegron111@gmail.com Received 7 August 2013; Accepted 10 December 2013; Published 29 January 2014 Academic Editor: Vega P´ erez-Gracia Copyright © 2014 O. Grøn and L. O. Boldreel. his is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Archaeological wrecks exposed on the sea loor are mapped using side-scan and multibeam techniques, whereas the detection of submerged archaeological sites, such as Stone Age settlements, and wrecks, partially or wholly embedded in sea-loor sediments, requires the application of high-resolution subbottom proilers. his paper presents a strategy for cost-efective, large-scale mapping of previously undetected sediment-embedded sites and wrecks based on subbottom proiling with chirp systems. he mapping strategy described includes (a) deinition of line spacing depending on the target; (b) interactive surveying, for example, immediate detailed investigation of potential archaeological anomalies on detection with a denser pattern of subbottom survey lines; (c) onboard interpretation during data acquisition; (d) recognition of nongeological anomalies. Consequently, this strategy difers from those employed in several detailed studies of known wreck sites and from the way in which geologists map the sea loor and the geological column beneath it. he strategy has been developed on the basis of extensive practical experience gained during the use of an of-the-shelf 2D chirp system and, given the present state of this technology, it appears well suited to large-scale maritime archaeological mapping. 1. Introduction 1.1. Background. From 1993 to 1996, a project at the National Museum of Denmark’s Centre for Maritime Archaeology, funded by the Danish National Research Foundation, pro- vided the opportunity to begin development of an approach to large-scale mapping and identiication of archaeological anomalies embedded in sea-loor sediments. Side-scan and multibeam systems are suited exclusively to the detection of anomalies visible as bathymetrical or microbathymetrical features on the sea loor. hey cannot detect anomalies located in sediments below this level. In contrast, subbottom proilers are able, on the basis of vertical proiles, to provide high-resolution information on archaeological features on the sea loor and those totally or partially embedded within the sediments beneath it. Since 1993, chirp subbottom pro- ilers have naturally become the technological mainstay in the development of methods for locating “thin” elements, or elements of restricted size, submerged in sea-loor sed- iments [1–5]. During this project it was seen as essential to develop a practically applicable strategy for large-scale mapping of sediment-embedded archaeological anomalies, based on of-the-shelf technology, which could readily be replicated by others. Furthermore, because a large part of Denmark’s submerged cultural heritage is located in shallow water (zero to a few metres of depth), it was essential that the seismic system employed could be used with acceptable results in water as shallow as 0.5 m. he aim of this paper is, through the presentation of a number of case studies, to demonstrate a cost-efective strategy for the large-scale mapping of submerged archaeological elements embedded in sea-loor sediments. It can also be useful to supplement surveys of larger objects, such as wrecks, with other types of subbottom proilers (boomers, sparkers, etc.). However, Hindawi Publishing Corporation Journal of Archaeology Volume 2014, Article ID 147390, 11 pages http://dx.doi.org/10.1155/2014/147390