Comparison of the Maritime Sites and Monuments Record with side-scan sonar and diver surveys: A case study from Rathlin Island, Ireland
01 Jun 2002-Geoarchaeology-an International Journal (Wiley Subscription Services, Inc., A Wiley Company)-Vol. 17, Iss: 5, pp 441-451
TL;DR: In this article, a side-scan sonar survey confirmed the presence of 46 targets of possible archaeological potential around Rathlin Island and 13 of these anomalies were positively identified as shipwrecks.
Abstract: Rathlin Island, off the north coast of Ireland, has a history of settlement and seafaring from the Late Mesolithic period to the present day. The maritime Sites and Monuments Record (SMR) for Rathlin indicates many wrecking incidents. In 1999, a reconnaissance side-scan sonar survey confirmed the presence of 46 targets of possible archaeological potential around Rathlin Island. Thirteen of these anomalies were positively identified as shipwrecks. Of the remaining 33 targets, nine were dived on in order to ground-truth the geophysical data. A successful and rapid methodology of ground-truthing side-scan sonar data for archaeological purposes was developed. The results confirmed the presence of a Danforth Anchor at one site, while the remaining anomalies were identified as geological features. The results from the side-scan survey and diver-truthing exercise enhanced the existing maritime SMR. (C) 2002 Wiley Periodicals, Inc.
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TL;DR: In this paper, the authors describe the first phase of the project "Archaeological Applications of the Joint Irish Bathymetric Survey (JIBS) Data" which analyzes bathymetric and backscatter data derived from multibeam surveys off the north coast of Ireland.
Abstract: This paper describes Phase 1 of the project ‘Archaeological Applications of the Joint Irish Bathymetric Survey (JIBS) Data’, analysing bathymetric and backscatter data derived from multibeam surveys off the north coast of Ireland. In particular, the usability of the data for shipwreck detection, identification and site characterization is explored. In Phase 1, the data was screened for anomalous sea-bed features, which were subsequently described, catalogued and categorized according to their archaeological potential and cross-referenced against existing records. A planned second phase of this project will examine each anomaly in greater detail together with the local and regional hydrodynamic conditions.
50 citations
Cites background from "Comparison of the Maritime Sites an..."
...The records frequently depend on post-18th century documentary evidence and word-of-mouth reports, or DECCA or latitude-longitude readings from sources varying from fishermen and sports divers to the Hydrographic Office (Quinn et al., 2002: 448)....
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TL;DR: The 3D chirp subbottom profiler provides high-resolution imaging of coastal and inshore seabed and subseabed structure by combining the known, highly repeatable source waveform of chirpprofilers with the coherent processing and interpretation afforded by true 3D seismic volumes as discussed by the authors.
Abstract: The 3D chirp subbottom profiler provides high-resolution imaging of coastal and inshore seabed and subseabed structure by combining the known, highly repeatable source waveformofchirpprofilerswiththecoherentprocessingand interpretation afforded by true 3D seismic volumes. Comprising 60 hydrophone groups arranged around a Maltese cross of four chirp transducers, 3D chirp permits acquisition of a true 3D volume with a horizontal resolution of 12.5 cm, providing an excellent base for shallow-water engineering, archaeological, military, and geologic studies. Here, we presentresultsfromsurveyinganatidalbasinonthesouthern coastofEnglandtomapbedrockprotrusionsandthesizeand distributionofburiedobjects.Thestudyareaof150250 m provided a series of unique challenges, including a large number of discrete objects ranging from tens of centimeters toseveralmetersinsize,buriedinathinveneer0.5to1.5 m of unconsolidated silt overlaying a flat bedrock surface that showed high acoustic contrast and short wavelength roughness. By comparing comprehensive postsurvey dredging of the entire site with a prestack time-migrated 3D volume, it is possibletoconfirma100%detectionrateforalldiscreteburied objects larger than 0.300.30 m in an illuminated area, although one acoustic anomaly could not be accounted for in thedredgingresults.
41 citations
Cites background from "Comparison of the Maritime Sites an..."
...subsurface. Consequently, there has been much recent work to develophigh-frequencysurface-scanningacoustics,e.g.,side-scansonar, sector-scanning sonar, and swath bathymetry, for object detection on the seabedSimms andAlbertson, 2000; Quinn et al., 2002 ....
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TL;DR: The backscatter responses of submerged archaeological material remain poorly understood, and a control experiment was conducted in Belfast Lough during July and August 2001 as discussed by the authors to address this, a selection of material and targets was arranged on the seabed in varying orientations.
39 citations
TL;DR: The results of two deep-water archaeological surveys recently conducted in the Aegean Sea, and the advantages of using conventional marine geological techniques in deepwater archaeology are presented in this article.
Abstract: This paper presents the results of two deep-water archaeological surveys recently conducted in the Aegean Sea, and the advantages of using conventional marine geological techniques in deep-water archaeology. Two Hellenistic wrecks were discovered: one in the Chios-Oinousses strait at 70 m, was a concentration of over 400 amphoras in a 1.5-m-high, high-backscattering, morphological high; the second, west of Kythnos island, at 495 m, consisted of a few amphoras scattered in a 20 × 20-m-wide area. Side-scan sonar was integrated with high-resolution sub-bottom profiling, and the integration of the two data-sets proved to contribute significantly to realistic interpretation of the sonar targets.
© 2007 The Authors
32 citations
TL;DR: The goal of this paper is to discuss the methodology of various search methods that are employed for submerged objects and how these various methods can be integrated as part of a comprehensive protocol for water searches depending upon the type of underwater terrain.
27 citations
References
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TL;DR: In this article, two models are proposed and presented to explain the sea-bed reflection in chirp data: the first incorporates changes in an acoustic impedance gradient at the sea bed; the second uses changes in the thickness of the uppermost sediment layer.
Abstract: Chirp sub-bottom profilers produce high-resolution images of the near-surface. An attribute of the sea-bed reflection in chirp data are fluctuations in polarity between adjacent traces. Two models are proposed and presented to explain this: the first incorporates changes in an acoustic impedance gradient at the sea bed; the second uses changes in the thickness of the uppermost sediment layer. Mixing of adjacent traces produces a consistent polarity for the sea-bed reflector. Reflection coefficients are calculated, using amplitude information derived from single-traces, and polarity information from trace mixing, with application to a marine archaeological case study. The reflection coefficient calculated for the top of a buried 18th century wooden wreck is -0.26.
60 citations
"Comparison of the Maritime Sites an..." refers background in this paper
...Although some research has focused on the geophysical signatures of anthropogenic materials submerged and buried in the marine environment (Quinn et al., 1997a; Bull et al., 1998; Newell, 1999), it remains a poorly understood subject....
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TL;DR: In this paper, the authors investigated the potential for imaging submerged and buried wooden artefacts in the marine environment using high-resolution seismic reflection techniques and developed models to calculate theoretical reflection coefficients of 11 wood species buried in shallow marine sediments.
Abstract: This paper investigates the potential for imaging submerged and buried wooden artefacts in the marine environment using high-resolution seismic reflection techniques. Models to calculate theoretical reflection coefficients of 11 wood species buried in shallow marine sediments are developed. The models use estimates of acoustic impedance contrasts to predict the strength of reflections resulting from buried wooden artefacts. Traditionally, wooden wrecks are composed of oak, with lesser components of mahogany, pine and elm. Experimental results on wood samples from a sixteenth century oak wreck (the Mary Rose) are presented as a control on theory. Results indicate that wooden wrecks may be readily imaged by a suitable sub-bottom profiler operating under appropriate survey conditions. Particular reference is made to Chirp sonar which transmits a frequency-modulated pulse, providing high-resolution digital seismic data. Chirp data acquired over an eighteenth century buried oak wreck (the Invincible, Horsetail, East Solent) is presented. Calculations of reflection coefficients acquired over the site support both the theoretically and experimentally derived data.
47 citations
TL;DR: In this article, the authors focus on desk-top assessments, non-intrusive evaluations such as fieldwalking and geophysical surveys, and the associated task of building Sites' and Monuments' Records (SMRs) to better quantify and manage the resource.
Abstract: Introduction Since the development-led boom in rescue archaeology in the 1960s and 1970s, the vicissitudes of funding and the growing recognition of the non-renewable nature of the archaeological resource, have prompted much more circumspect attitudes to excavation (Cleere, 1989; Hunter & Ralston, 1993). Hence the justification of decisions to excavate are generally based either on the threat from development or other agency, or the need for research, where excavation is viewed as the best or only way to answer certain questions, or occasionally both. As a result, greater emphasis is now based on desk-top assessments, non-intrusive evaluations such as fieldwalking and geophysical surveys, and on the associated task of building Sites’ and Monuments’ Records (SMRs) to better quantify and manage the resource. Over the same period archaeology underwater focused on the development of appropriate excavation and recording methods and the collection of data. Since the mid 1980s, this area of research has moved in a broadly similar direction, concentrating less on the excavation of single sites (often as a reaction to chance discoveries) and more on assessment and recording. An increasing number of projects in coastal regions are more proactive in character, involving regionally
45 citations
TL;DR: Chirp sub-bottom profiler and repeat sidescan sonar imaging of the Invincible wreck site (1758) in the Solent (U.K.), interpretation, and implications for management of the site.
Abstract: Chirp sub-bottom profiler and repeat sidescan sonar imaging of the Invincible wreck site (1758) in the Solent (U.K.), interpretation, and implications for management of the site.
24 citations
TL;DR: In this paper, a suite of geophysical equipment including a side-scan sonar, a Chirp sub-bottom profiler and a proton precession magnetometer were used for seabed mapping in an attempt to record the submerged and buried archaeological resource.
Abstract: Northern Ireland has been subject to significant maritime influences throughout its 9000-year known human history. In 1997 the University of Ulster in partnership with the Environment and Heritage Service (DoE, NI) embarked on a programme of seabed mapping in an attempt to record the submerged and buried archaeological resource using a suite of geophysical equipment including a side-scan sonar, a Chirp sub-bottom profiler and a proton precession magnetometer. The geophysical research programme has successfully imaged 80 19th- and 20th-century wrecks, and 20 targets of further archaeological potential. These data will aid the production of wreck-prediction indices for the coastline of Northern Ireland based on site formation processes and site stability. This information will make valuable additions to both Sites and Monuments Records and to the shipwreck database currently under consideration at the University of Ulster. Copyright 2000 The Nautical Archaeology Society
18 citations
Additional excerpts
...The Rathlin Island case study is one component of an ongoing Department of Environment for Northern Ireland sponsoredMarine Geophysical Investigation of the Inshore Coastal Waters of Northern Ireland (Quinn et al., 2000)....
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