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Seafloor mapping is closely related to studying and understanding the ocean, which has increasingly raised interest in the past years. Coastal management, habitat loss, underwater cultural heritage, natural disasters, marine resources and offshore installations have underlined the need of charting the seabed. This upturn has been encouraged by many national and international initiatives and culminated in the declaration of the Decade of Ocean Science for Sustainable Development (2021-2030) by the United Nations, 2017. Novel Underwater cloud services offered through the EC H2020 NEANIAS project support this joint quest by implementing Open Science procedures through the European Open Science Cloud (EOSC). The services produce user-friendly, cloud-based solutions addressing bathymetry processing, seafloor mosaicking and classification. Hence, NEANIAS Underwater services target various end-users, representing different scientific and professional communities by offering three applications.The Bathymetry Mapping from Acoustic Data (UW-BAT) service provides a user-friendly and cloud-based edition of the well known open-source MB-System, via Jupyter notebooks. This service produces bathymetric grids and maps after processing the data throughοut a flexible and fit-for-purpose workflow by implementing sound speed corrections, applying tides, filters and choosing the required spatial resolution.The Seafloor Mosaicking from Optical Data (UW-MOS) service provides a solution for representing a large area of the seafloor, in the order of tens of thousands of images, and tackling visibility limitations from the water column. The service performs several steps like camera calibration, image undistortion, enhancement, and quality control. The final product could be a 2D image Mosaic or a 3D model.The Seabed Classification from Multispectral, Multibeam Data (UW-MM) service focuses on seabed classification by implementing cutting-edge machine learning techniques and at the same time providing a user-friendly framework. The service unfolds within four steps: uploading the data, selecting the desired seabed classes, producing the classification map, and downloading the results.Therefore, NEANIAS Underwater services exploit cutting-edge technologies providing highly accurate results, regardless of the level of expertise of the end-user, and reducing the time and cost of the processing. Moreover, the accessibility to sophisticated services can simplify and promote the correlation of interdisciplinary data towards the comprehension of the ocean, and the contribution of these innovative services is expected to be of high value to the marine community.

International audience; 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 micro-structure. 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.

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Non-invasive geophysical methods have been increasingly applied in geoarchaeological research commonly showing the need of data calibration based on stratigraphical information deduced from outcrops or sediment cores. In this contribution, a methodological approach combining two-dimensional (2D) electrical resistivity tomography (ERT) and stratigraphical data based on coring and, for the first time in geoarchaeological research, direct-push electrical conductivity (DP-EC) logging is presented and discussed. The approach yields high resolution data based on studies of two different types of archives, the Holsterburg site in central Germany located in a fluvio-terrestrial zone and the Corfu City site in Greece located in a near-coastal zone. It is shown that DP-EC logs trace fluctuations over grain size in high resolution which reflect changes of depositional conditions in the course of time. In addition, constraints from DP-EC logs in the form of layer interfaces and electrical resistivities were incorporated into the ERT inversion process minimizing the ambiguity of inversion results. It is shown that incorporating regions with certain starting resistivities based on DP-EC logs exceed the advantage of using layer interfaces alone. It is concluded that in future geoarchaeological and geomorphological studies a combined application of coring, DP-EC logging and ERT measurements should be considered as a standard approach towards a more comprehensive stratigraphical characterization of the shallow subsurface. Copyright (c) 2016 John Wiley & Sons, Ltd.

In this paper, we present for the first time geomorphological, sedimentary and microfaunal evidence of palaeotsunami impact on Corfu (Ionian Islands, Greece). The island of Corfu is located in an area of exceptional tectonic stress: towards the south, the African oceanic plate is being subducted underneath the Aegean plate, whereas towards the north, the Adriatic and European plates form a continental collision zone. Recent publications provide evidence of earthquake related co-seismic movements that potentially trigger extreme wave events as well as relative sea level fluctuations. In this context, we investigated two selected near-coast geological archives – the Chalikiopoulou Lagoon in the east and the Korission Lagoon in the southwest of Corfu Island. Our results clearly document that the eastern as well as the southwestern coasts of Corfu were repeatedly affected by palaeotsunami impact during the Holocene. With regard to the local topographical constellation and the recent geomorphodynamic potential of each study area, evidence of high-energy wave impact is based on the stratigraphical and microfaunal record of selected vibracoring sites as well as on numerical modelling results. It is concluded that the eastern coast of Corfu is preferably affected by high-energy wave impacts from a southern direction. Such impacts are most likely related to teletsunamis from the major seismical zone of the Hellenic Trench. In contrast, the southwestern coast of Corfu is endangered by impacts from both western and southern directions. Such impacts may comprise teletsunamis triggered in the Hellenic Trench or the Etna regions but may also be caused by local submarine landslides at the steeply sloping continental shelf directly west of Corfu. Our study builds a bridge between palaeotsunami-research conducted in the southern Ionian Sea and the Adriatic Sea and allows to better discriminate between the effects of teletsunamis and locally triggered events within one of the seismically most active regions in the eastern Mediterranean.

The Late Bronze Age (LBA) tsunami and the A.D. 365 tsunami are supposed to have affected the northern coasts of Crete. However, near-coast sedimentary archives have been rarely investigated in this area, and sedimentary archives including palaeotsunami fingerprints are still unknown. The main objective of our research was to search for appropriate tsunami sediment traps in order to gain detailed insights into the Holocene palaeotsunami history of northern Crete. We found an excellent fine sediment archive near Pirgos, located to the west of Rethymnon. Based on a multi-electrode geoelectrical survey and an 11-m-deep sediment core, we analysed the event-geochronostratigraphical record by means of sedimentological, geochemical, geochronological, geomorphological, and microfossil investigations. The Pirgos record revealed a thick unit of homogeneous mud of a lagoonal environment starting ~6000 years ago. The lagoon was affected by five high-energy events, leaving layers of allochthonous sand. Microfossil analyses of these layers revealed a mixed foraminiferal assemblage including species from brackish habitats but also displaced and transported species from open marine and deep-water environments. Considering sedimentary characteristics, the local wave climate of the Cretan Sea, and the overall geomorphological setting, we interpret these layers as related to extreme wave events (EWE). Based on a local radiocarbon age-depth-model, we identified one EWE layer as a reliable candidate for the LBA Santorini tsunami. Another EWE layer is most probably associated with the A.D. 365 tsunami. This EWE ended abruptly the lagoonal conditions at Pirgos because of to the 1.64 m coseismic uplift at the site. The Pirgos lagoon existed between the first half of the 6th mill. B.C. and (at least) the end of the 2nd mill. B.C. We found that the area around Pirgos has continuously subsided over 3000 or so years, reflecting constant tectonogeomorphological conditions dominated by the nearby subduction zone between the Aegean and African plates.

Les contributions scientifiques relatives au port antique de Fos sont regroupées dans les pages 18 à 47.; Catalogue de l'exposition tenue dans le souterrain de l'Hauture, à Fos-sur-Mer, en 2019.

Programme collectif de recherche piloté par le Département des Recherches Archéologiques Subaquatiques et Sous-Marines et le Centre Camille Jullian-UMR7299.lieu de consultation : DRASSM; International audience

In antiquity, the harbour-city of Corcyra (modern: Corfu) was a prevailing naval power in the Mediterranean and had several harbours to host a considerable fleet. Today, these harbours are totally or partly silted and concealed under modern urban infrastructure. Comprehensive geoarchaeological studies were conducted on the northeastern fringe of the Analipsis Peninsula where excavations have revealed the archaeological remains of a massive quay wall (Pierri and Arion sites). These remains are located east of known ancient harbour structures that belong to the Alkinoos Harbour. Our study aimed to reconstruct the palaeoenvironmental setting of the harbour facilities at the Pierri site, including the analysis of the local sedimentary record in order to detect and differentiate natural and man-made triggers that caused environmental shifts. At the Pierri site, we found geoarchaeological evidence for an ancient harbour basin related to the prominent quay wall. Associated harbour sediments indicate a protected harbour which was developed from an open shallow marine environment, most probably by the construction of breakwaters. Harbour deposits were dated using radiocarbon analyses and diagnostic ceramic fragments to the 4 th to 3 rd cent. BC. This is in good agreement with the age of the harbour installations as such archaeologically assigned to the Classical and Hellenistic period. The Pierri site was possibly in function as a harbour facility even before the 4th cent. BC. In any case, it was strongly hit by an earthquake and associated tsunami event during Classical to Hellenistic times. By this event, the harbour was uplifted and covered by event deposits so that it was not usable any more. It was subsequently buried by anthropogenic and colluvial sediments. Overall, the Pierri coastal archive allowed to identify three distinct tsunami landfall events, namely before 2483–2400 cal BC (event I), after 2483–2400 cal BC and before 370–214 cal BC (event II), and during Classical to Hellenistic times, most probably between the 4 th and 3 rd cent. BC (event III). Another tsunami event (event IV) potentially hit the site when it was dry land. Ages of tsunami events I–II and candidate tsunami IV are consistent with tsunamis known from the coasts of western Greece and southern Italy and where thus classified as supra-regional tele-events. Event III was identified as associated to a local earthquake and tsunami by which Corfu Island was uplifted and, at the same time, tilted with a vertical offset of 1.74 m from W to E.

The southwestern coast of Crete, one of the most seismically active regions in Europe, experienced co-seismic crust uplift by 9 m during the Ms = 8.3 mega-earthquake that struck the eastern Mediterranean world on 21 July AD 365. An associated tsunami event caused thousands of fatalities and destroyed many coastal settlements and infrastructure between the Levante in the east and the Adriatic Sea in the northwest. So far, coastal sedimentary archives in southwestern Crete including distinct palaeotsunami fingerprints are rarely investigated. Therefore, a multi-proxy study including sedimentological, geochemical, geochronological, and microfaunal methods was conducted in order to detect onshore coastal sedimentary archives that functioned as fine sediment traps and document palaeotsunami imprint. We found adequate archives at the Sougia and Palaiochora coastal plains that were used to reconstruct the palaeogeographical evolution and the palaeoseismological history of SW Crete during the late Holocene. Our studies revealed distinct geomorphological, sedimentological, geochemical, and microfaunal traces of high-energy impact from the marine side related to seismic events. At the Sougia coastal plain a sheet of fine sand with a neat microfossil and geochemical fingerprint was found sandwiched between underlying pre-tsunami muds and overlying post-tsunami colluvial silt. In the Palaiochora coastal plain, tsunami overflow of a flat Neogene bedrock platform led to the accumulation of sand-dominated deposits that were subsequently covered by colluvial material from the adjacent hillslopes. Based on radiocarbon and luminescence dating approaches, it is shown that the AD 365 tsunami event is the best-fit candidate for the tsunami-related sediments deposited at both, Sougia and Palaiochora. This study, for the first time, presents multi-proxy evidence of the AD 365 tsunami imprint on fine-sedimentary archives along the western and southwestern coast of Crete.

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lieu de consultation : DRASSM

Published archaeological, palaeoenvironmental, and palaeoclimatic data from the Peloponnese in Greece are compiled, discussed and evaluated in order to analyse the interactions between humans and the environment over the last 9000 years. Our study indicates that the number of human settlements found scattered over the peninsula have quadrupled from the prehistoric to historical periods and that this evolution occurred over periods of climate change and seismo–tectonic activity. We show that societal development occurs both during periods of harsh as well as favourable climatic conditions. At some times, some settlements develop while others decline. Well-known climate events such as the 4.2 ka and 3.2 ka events are recognizable in some of the palaeoclimatic records and a regional decline in the number and sizes of settlements occurs roughly at the same time, but their precise chronological fit with the archaeological record remains uncertain. Local socio-political processes were probably always the key drivers behind the diverse strategies that human societies took in times of changing climate. The study thus reveals considerable chronological parallels between societal development and palaeoenvironmental records, but also demonstrates the ambiguities in these correspondences and, in doing so, highlights some of the challenges that will face future interdisciplinary projects. We suggest that there can be no general association made between societal expansion phases and periods of advantageous climate. We also propose that the relevance of climatic and environmental regionality, as well as any potential impacts of seismo-tectonics on societal development, need to be part of the interpretative frameworks.

International audience; At the ancient site of Akko/Acre, positioned on the northern side of the Haifa Bay, habitation patterns and anchorage locations changed over time. Causes for this are attributed to ecological and geomorphological fluctuations as well as the impact of human processes. The area is influenced by the silt deposited by the River Na'aman, and coastal sedimentation controlled by littoral currents. Akko/Acre is a UNESCO World Heritage Site and one of the oldest continuously inhabited sites in the area. This article reviews a variety of attempts using ground penetrating radar, electric resistivity tomography, coring, and limited archaeological excavations, to reveal the changing locations of anchorages and harbours, and link these to variations in habitation patterns.