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High resolution side scan sonar sonograph acquired at 900 kHz frequency in the examined area. (1): ancient shipwreck, (2): sedimentary seafloor substrates (medium to low reflectivity), (3): rocky substrates with elevation and microrelief (high reflectivity), (4) target of unknown origin, (5): anchoring marks.
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In the present paper we present the marine remote surveying conducted aiming to investigate an ancient shipwreck offshore Kefalonia island, in Ionian Sea, Greece. Within the framework of the survey efforts were given to examine the site formation of the wreck and to define the best practices for the detection and mapping of similar potential archae...
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... on the above backscatter and shape characteristics that site was considered to be the ancient shipwreck and led the fol- lowing field surveying to focus there. Figure 3 shows the sonograph of the studied area retrieved with 900 kHz frequen- cy. The site considered as the most possible for the ancient wreck appears here with a more clearly acoustic signal (Fig. 3). ...
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... backscatter and shape characteristics that site was considered to be the ancient shipwreck and led the fol- lowing field surveying to focus there. Figure 3 shows the sonograph of the studied area retrieved with 900 kHz frequen- cy. The site considered as the most possible for the ancient wreck appears here with a more clearly acoustic signal (Fig. 3). The large acoustic shadow zone which ac- companies the area implies elevation in relation to the surround seafloor and the strong patchy acoustic character suggests microrelief and material aggregation with- in the area. Photos obtained by drop camera confirmed the existence of the ship- wreck at the examined area and ascribed the ...
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... gap between mounds -i-and -ii-could be the result of human intervention in the wreck remains. An anchoring in the past could have drifted down slope these amphorae. The detec- tion of trenching marks due to anchoring on the seafloor, very close to the shipwreck, further suggests that modern vessels and their anchoring could damage the wreck site (Fig. 3). In order to verify all the above hypothesis regarding the wreck formation processes, a systematic archaeological excavation is ...
Citations
... These objects are considered an essential part of our cultural heritage and are part of our collective planetary history. They play an important role from the scientific, political, cultural, and economic point of view [9,10]. The presence of a large number of well-preserved wrecks was influenced by geographical, historical and political factors. ...
Multibeam echo sounders (MBES), side-scan sonars (SSS), and remotely operated vehicles (ROVs) are irreplaceable devices in contemporary hydrographic works. However, a highly reliable method of identifying detected wrecks is visual inspection through diving surveys. During underwater research, it is sometimes hard to obtain images in turbid water. Moreover, on-site diving operations are time-consuming and expensive. This article presents the results of the remote sensing surveys that were carried out at the site of a newly discovered wreck, in the southern part of the Baltic Sea (Poland). Remote sensing techniques can quickly provide a detailed overview of the wreckage area and thus considerably reduce the time required for ground truthing. The goal of this paper is to demonstrate the process of identification of a wreck based on acoustic data, without involving a team of divers. The findings, in conjunction with the collected archival documentation, allowed for the identification of the wreck of a Junkers Ju-88, a bomber from World War II.
... The microtidal regime of the Mediterranean Sea along with the carbonate rocky shores and bioconstruction favors the development of precise and well-preserved paleo sea-level archives (Boulton and Stewart, 2015;Furlani et al., 2014). Thus, the currently submerged areas accommodate a large number of natural paleo-RSLi shaped during previous sea-level stillstands and/or slowdowns, but also archaeological testimonies due to the great maritime tradition (Geraga et al., 2015Ferentinos et al., 2020;Georgiou et al., 2021a;Papatheodorou et al., 2021). Although discovering submerged paleo-landscapes is of utmost importance and can be accomplished through integrated methodological approaches (Georgiou et al., 2021b), the literature regarding their existence is quite limited due to the difficulties in mapping, collecting, and dating underwater data (Bilbao-Lasa et al., 2020). ...
Important evidence related to sea-level fluctuation, human evolution and dispersal that took place onshore during the Late Pleistocene and Holocene eras, are currently found underwater due to the sea-level rise. In this study, we present submarine relative paleo sea-level indicators found offshore the Lebanese coastline, at large from the prominent ancient city of Byblos. Two different submarine erosional terrace sequences were identified at depths ranging from −40 to −25m (“distant” sequence) and −11 to 0m (“nearshore” sequence) below present sea level, by using a combination of high-resolution geophysical means and terrain data analysis techniques. In the absence of datings, a model that uses relative sea-level curves for different uplift rates and examines the terraces' formation for various cliff retreat rates (derived from literature and on-field GPS measurements) was built. This model indicates the most possible time frames of the submarine terraces’ (STs) formation. The “nearshore” terrace sequence is suggested to have originally been formed during Marine Isotope Stage 5a (MIS5a) sea-level highstand, while it was possibly re-flattened during the first MIS1 sea-level slowdown (8–6 ka BP). The “distant” sequence formation is placed between the MIS4 to MIS3 transition (∼62–50 ka BP), and during MIS3 sea-level highstands within 45–35 ka BP. It was also found that a long-term uplift rate of 0.28–0.37 mm/a and cliff retreat rate of 0.03–0.09 m/a best fit our data and existing onshore relative sea-level indicators. The formation of the STs at this time was further supported by chronologically intercurrent uplifting events that facilitated their formation and preservation. Finally, our model supports recent ice-sheet reconstructions related to higher MIS3 values since sea-level curves that were tested for this scenario (eustatically reaching up to −37/-38m depth), proved more successful in the formation of the “distant” sequence.
... In the field of marine geophysics, wreck site assessments based on integrated geophysical survey techniques have been extensively reported through the literature in the past years [1][2][3][4]. These techniques provide the researchers with big volumes of geophysical data, usually in a fraction of the time, utilising geophysical instruments synchronously over the survey area. ...
Through the study of three wreck sites over the Methoni Bay (Greece), this article presents the benefits of spatio-temporal integration and correlation of marine geophysical data in a common three-dimensional (3D) geographical platform for analysis, and visualisation of shipwreck ruins and for interpretation of physical processes over wreck sites. The integration of 3D datasets has been proven to support identification of archaeological features over and under the seafloor, evaluation of the wreck structure state, and assessment on the wrecking event and the wreck site arrangement at that time, due to interactive cross-examination of datasets acquired in separate planes. Data synthesis is fundamental for 3D digital reconstruction of scattered and partially buried shipwreck ruins in complex geology as every dataset acts as interpretive and complimentary to each other. It is also shown that data synthesis highlights the signatures of physical processes over the wreck sites, and the interaction between the processes and the shipwrecks. The analysis of spatio-temporal, four-dimensional (4D) integrated datasets has proved to provide knowledge on the wreck site evolution through time, and highlights the disturbance of underwater archaeological resources due to human activities. The study has also shown that the creation of a shoalest depth true position bathymetric surface supports the realistic 3D wreck representation over the seafloor.
... The profile created through this is interpreted based on their continuity, sharpness, distinctiveness, and amplitude [85]. SBP is widely used in marine geo-archaeology for the reconstruction of paleogeography and the detection of buried features of archaeological interest [32,35,86]. SBP, while crucial to the detection of underwater antiquities, is not so widely used for mapping benthic habitats. ...
The rising human activities and resource exploitation have increased pressure in the coastal zone and the marine environment, risking the very existence of Marine Priority Habitats (MPH) and Underwater Cultural Heritage (UCH). The delimitation of these two priority areas in a time-and cost-effective way is essential for the sustainable management and exploitation of sea resources and natural-cultural heritage preservation. We propose an Integrated Methodological Approach for the Detection and Mapping of MPH and UCH. To achieve this, we used a downscale methodological approach of increasing spatial resolution based on three main methodological axes: (i) desk-based research, (ii) marine geophysics/seafloor classification, and (iii) in-depth visual inspection/3D mapping. This methodological scheme was implemented at the Saronic Gulf and focused on Aegina island. The methodology proposed, which combines existing and new techniques, proved successful in detecting and mapping the MPH and UCH in detail, while it compiled the information necessary for the establishment of Marine Spatial Planning (MSP) maps. Finally, the MSP map constructed for the Saronic Gulf demonstrated the lack of holistic coastal zone management plans due to impacts on UCH linked to anthropogenic intervention and the sparsity of marine habitats owing to marine pollution.
... Marine geophysical techniques are widely used in geoarchaeological surveys for the detection and mapping of submerged archaeological sites [7], shipwrecks [8][9][10][11], but also the reconstruction of coastal paleogeography [12,13]. By using multibeam and sidescan sonars scientists are able to acquire detailed bathymetric and backscatter intensity data respectively. ...
The documentation of underwater cultural heritage (UCH) is the basis for sustainable maritime development including its protection, preservation, and incorporation in coastal zone management plans. In this study, we present a multidisciplinary, non-intrusive downscale approach for the documentation of UCH implemented on the coastal area of Aegina Island, Greece, where a unique submerged harbour complex is preserved. This approach succeeded in obtaining information that serves both geomorphological and archaeological purposes in a time-and cost-effective way, while obtaining information of centimeters to millimeters scale. The geomorphology of the area was mapped in detail through marine geophysical means while ancient submerged conical rubble structures and breakwaters were documented using automatic seafloor segmentation techniques, revealing previously unknown sites of archaeological interest. The structures' parameters were extracted from the acoustic data to analyze their morphometry, while photogrammetry was realized using a Remotely Operated Vehicle to expose their microstructure. The spatial distribution of the structures revealed the construction of a well-planned harbour complex with multiple passages and different possible functionalities. Finally, through the structures' morphometric analysis (geometry and terrain statistical parameters) their preservation status was revealed, demonstrating the anthropogenic impact on the submerged ancient structures due to the modern harbor activity.
... That innovative survey was the opening of a new era in archaeological oceanography in the Greek and eastern Mediterranean Sea, where the seafloor shelters the remains of glorious moments in prehistoric and historic times of the civilizations that developed on the surrounding coastline. A series of respective surveys would follow, attempting to investigate ancient and historic shipwrecks, naval battles and marine routes in Greek seas by using remote sensing techniques [3][4][5][6][7][8][9][10]. Over the last 15 years, marine remote sensing techniques have proven themselves in underwater archaeology predominately to be effective and reliable means of detecting ancient and historic shipwrecks and for site-specific archaeological surveys [11][12][13][14]. ...
A series of marine remote sensing and ground-truth surveys were carried out at NW Gulf of Patras (W. Greece). The same area was surveyed in 1971 by Throckmorton, Edgerton and Yalouris, who are among the pioneers in the application of remote sensing techniques to underwater archaeology. The researchers conducted a surface reconnaissance survey to locate the site where the Battle of Lepanto took place on 7 October 1571. Their remote sensing surveying resulted in a map of two "target" areas that showed promise as possible remnants of wrecks from that battle and proposed a ground truth survey for their identification and in the detection of two modern shipwrecks. The ground truth survey was never fulfilled. The objectives of our repeat surveys, which were completed 50 years later, were to relocate the findings of this pioneer survey with higher spatial and vertical resolution, to ground-truth the targets, fulfilling their investigation, and to interpret the newly collected data in the light of modern developments in marine geosciences. Our repeat surveys detected mound clusters and individual mounds referred to "target" areas. These mounds could be interpreted as the surface expression of mud and fluid expulsion from the underlying deformed soft sediments. The ground truth survey demonstrated that the tops of mounds represent biogenic mounds. The ROV survey did not show any indication of wreck remnants of the Battle of Lepanto within the two survey areas. The site formation processes of the two modern shipwrecks were also studied in detail. Two noticeable seafloor morphological features were detected around the wreck sites; field of small-sized pockmarks and seafloor depressions. We would like to dedicate this work to the memory of Peter Throckmorton and Harold E. Edgerton, who are among the pioneers in the formative years of underwater archaeology in Greece.
... Remote sensing equipment and vehicles have great potential in hydrography, offshore industry, and marine archeology. They are also excellent at mapping shipwrecks or planes at various depths [10]. Their efficiency and testing accuracy significantly depend on the adopted measurement methodology and the so-called good hydrographic practice. ...
New shipwrecks are usually found during other work at sea. In 2006, the research vessel St. Barbara discovered probably the most massive wreck that lies on the bottom of the Baltic Sea. Its identity was unknown, and the Arctowski was sent to conduct research. In this study, the author describes how an adequately selected research methodology using remote sensing technology can lead to obtaining precious and accurate measurement data. The article proposes an appropriate approach to identifying the most massive underwater object in the Baltic Sea. The results of bathymetric and sonar tests are presented. Unconventional use of scanning sonar, which was undoubtedly not foreseen by the manufacturer, was also proposed. The article also shows how some remote sensing techniques support and complement each other when verifying objects on the bottom. Moreover, this paper addresses the impact of sonar frequency and survey methodology on image resolution and data quality. If imaged under the right conditions, side-scan sonar can deliver records based on which shipwreck identification is possible. The wreck of the aircraft carrier lies at the bottom of the Baltic Sea at a depth of about 90 m. Some difficulties in measurements were caused by the lack of a depressor, the use of a light cable line, or the lack of a standard side-scan sonar winch. However, these limitations did not significantly affect the quality of the recorded data. The research results prove that the proposed methodology for using side-scan sonar (SSS) or scanning sonar is correct, and the obtained measurement data make it possible to identify the detected object at the level of 99%.
... A detailed analysis of the "Fiskardo" shipwreck has been presented in [30,31]. In this section only the most important points-relevant to the present work-as analyzed in [30] are mentioned. ...
... The shipwreck is a Roman period wreck, dated between 1st century BC and 1st century AD. The dating was based on the type of the amphorae found [31]. The shipwreck is lying on a muddy seafloor and her debris field is small and scattered at a distance approximately 8 m around the wreck. ...
... In such a case, a small-scale and site-specific survey is needed in order to provide detailed sonar images of the highlighted objects/anomalies in the large-scale survey. The main aim of those detailed surveys is to maximize the separation between potential ancient shipwreck and other seafloor features such as scattered outcropping rocks and coralligenous communities, Posidonia oceanica and sea-grass prairies, which may have similar acoustic signature in the side scan sonar records [30,31]. ...
Underwater cultural heritage (UCH) sites constitute an important part of the overall cultural heritage both nationally and globally as they carry cultural, environmental, scientific, technological, political, economic and social viewpoints. UCH includes not only submerged sites and buildings, but also vessels and aircrafts. The Inner Ionian Sea in Greece is a place rich in a significant number of shipwrecks with a timespan ranging from ancient times right through to the 20th century. The results herein present the study of ancient, World War I (WWI), World War II (WWII) and more recent shipwrecks in the inner Ionian Sea. A total of 11 out of 36 known shipwrecks in the area have been systematically studied using marine remote sensing and ground truthing techniques. The marine remote sensing sensors include: side scan sonars, sub-bottom profilers and multi-beam echo-sounders. At each wreck site, the condition of the wreck, the debris field and man-made activities were determined based mainly on acoustic data. The history of each wreck is also briefly documented. The conclusion of the current research work is that there is an immediate need for a shipwreck protection framework in the Inner Ionian Sea; wrecks included in this work are a highly important part of UCH and man-made activities (e.g., fishing) threaten their integrity.
... The above presented SSS and "chirp" SBP data showed that the ship's dimensions would have been about 34 m long and 13 m wide, as the cargo's measured length and width is 30 and 12 m, respectively, whilst the hull height is about 3.3 m. The shipwreck, based on the type of the amphorae (Fig. 5b), is dated at between 1 st century BC and 1 st century AD (Geraga et al., 2015) and therefore, it is considered as a Roman period wreck. The dimension of the shipwreck makes it one of the four largest merchant shipwrecks from the above-mentioned period, that have been found in the Mediterranean to date. ...
... The elongated oval shaped mound of amphorae on the seafloor displayed on the sidescan sonar record and the photomosaic ( Fig. 5a and b) resembles the outline of ships of that period, as defined by the ship's side rail. This indicates that the cargo has kept the outline of the ship and along with the almost flat and gently sloping seafloor that prevails around the shipwreck (Fig. 4a) suggest that the ship sank very slowly in an up-right position and came to rest on its keel and then gradually tipped to one side with the hull keeping its overall structure, intact (Geraga et al., 2015). ...
... Furthermore, the shipwreck's sonar image and photo-mosaic show that the amphorae assemblage is crossed by a linear trench-zone about 1 m wide cleared of amphorae (Fig. 5a b). This zone, as suggested by Geraga et al. (2015), probably resulted from a vessel dragging an anchor over the seafloor during anchoring maneuvering. The presence on the seafloor of anchor dragging traces in the vicinity of the shipwreck is probably related to anchoring at the entrance to the Fiscardo embayment. ...
... The in situ preservation of underwater cultural heritage sites, proposed in these strategies as first option, requires the application of non-destructive and cost-effective methods to first locate and assess the archaeological sites, and then monitor and preserve them. For the detection, mapping, and study of underwater archaeological sites, state-of-the-art marine geophysical techniques [6][7][8][9][10], underwater photography, and photogrammetry [11] have been used as standalone techniques or in compilation, depending on the nature and the environmental conditions of the sites. The combined application of the marine geophysical and ground-truthing techniques (multibeam echosounders, side-scan sonars, sub-bottom profilers, marine magnetometers, and photogrammetry) provides an integrated information environment that is crucial for the understanding of archaeological deposits, in the management of sites, and in planning strategies for site excavation. ...
... The establishment of diving sites in the area would benefit from the distribution of the cultural heritage items, since the northern group of antiquities is very close to the shore and sheltered from the north winds, while the southern group lies one nautical mile off Methoni, sheltered from the south winds. An analysis of geophysical data and archaeological evidence [9,10] at short temporal scales show that the alongshore sediment transport processes affect the exposure of archaeological material close to the Methoni shore in a way that the burial of wreck sites and parts of settlement ruins in shifting sand coincides with the exposure of other remnants. Thus, the overall potential of exploitation of sites remains high. ...
The ‘Evolved GE.N.ESIS Project’ highlights the underwater cultural heritage resources off the coast of Methoni, Greece that could locally drive sustainable socioeconomic growth. An integrated marine geophysical survey, a hydrographic survey, and a GNSS survey were conducted off Methoni, recording six historic wreck sites, artefacts, the ruins of a submerged prehistoric settlement, and the town's ancient harbour/breakwater, as well as the geophysical properties of the underwater environment. The preliminary project results present bathymetric surfaces, backscatter intensity and magnetic maps, drawings, and seismic reflection profiles of the underwater antiquities and of the seabed, all fused in a 3D geographical platform. The results also shed light on the archaeological potential of the site, the nearshore physical processes, and their effect on the underwater archaeological resources. The project outcomes have shown that the establishment of an underwater archaeological park and diving sites at the cultural heritage sites will support cultural tourism development in the area and will have a positive impact on local socioeconomic development. The underwater archaeological park should comply with the basic principles of a site management plan – one that is established in the context of an integrated coastal management plan that identifies the maritime synergies or conflicts among human activities, archaeological resources, and the local environment, and utilises the 3D synthesis of marine knowledge from the project outcomes as a decision-making tool.
