Impact of Holocene tsunamis detected in lagoonal environments on Corfu (Ionian Islands, Greece): Geomorphological, sedimentary and microfaunal evidence

Abstract 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 La…

Landscape reconstruction and major flood events of the River Main (Hesse, Germany) in the environs of the Roman fort at Groβkrotzenburg

Abstract Detailed geoarchaeological studies were conducted at the Groβkrotzenburg floodplain (Southern Hesse, Germany) in order to reconstruct the fluvial palaeogeography and search for Roman harbour installations. Another objective was to reconstruct the local flood history based on stratigraphic and geochronological data. Prospection based on electrical resistivity tomography, vibracoring and direct push electrical conductivity logging were carried out to detect and analyze subsurface stratigraphies. Altogether, 6 sediment cores, up to 7 m long, were drilled along transects along and perpendicular to the present course of the River Main. Based on sedimentological and geochemical data, we …

Potential and limits of combining studies of coarse- and fine-grained sediments for the coastal event history of a Caribbean carbonate environment

The coastal deposits of Bonaire, Leeward Antilles, are among the most studied archives for extreme-wave events (EWEs) in the Caribbean. Here we present more than 400 electron spin resonance (ESR) and radiocarbon data on coarse-clast deposits from Bonaire’s eastern and western coasts. The chronological data are compared to the occurrence and age of fine-grained extremewave deposits detected in lagoons and floodplains. Both approaches are aimed at the identification of EWEs, the differentiation between extraordinary storms and tsunamis, improving reconstructions of the coastal evolution, and establishing a geochronological framework for the events. Although the combination of different method…

Tracing tsunami signatures of thead551 andad1303 tsunamis at the Gulf of Kyparissia (Peloponnese, Greece) using direct pushin situsensing techniques combined with geophysical studies

Dyke failures in the Province of Groningen (Netherlands) associated with the 1717 Christmas flood: a reconstruction based on geoscientific field data and numerical simulations

AbstractThe 1717 Christmas flood is one of the most catastrophic storm surges the Frisian coast (Netherlands and Germany) has ever experienced. With more than 13,700 casualties it is the last severe storm surge with a death toll of this order. At the same time, little is known about the hydrodynamic conditions and the morphological effects associated with this storm surge.In this study, 41 potential dyke failures in the Province of Groningen (Netherlands) associated with the 1717 Christmas flood were systematically reconstructed and mapped by using historical maps and literature and by analysing the recent topography in search of typical pothole structures and sediment fans. The dimensions …

Combined Electrical Resistivity Tomography (ERT), Direct-Push Electrical Conductivity (DP-EC) Logging and Coring - A New Methodological Approach in Geoarchaeological Research

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 C…

The sedimentary and geomorphological imprint of the AD 365 tsunami on the coasts of southwestern Crete (Greece): Examples from Sougia and Palaiochora

Abstract 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 det…

Detection and localization of chamber tombs in the environs of ancient Olympia, Peloponnese, Greece, based on a combination of archaeological survey and geophysical prospection

Geoarchaeological evidence of marshland destruction in the area of Rungholt, present-day Wadden Sea around Hallig Südfall (North Frisia, Germany), by the Grote Mandrenke in 1362 AD

Abstract Geophysical and geoarchaeological investigations were carried out in the Wadden Sea of North Frisia (Schleswig-Holstein, Germany) to elucidate major environmental changes that considerably altered the coastal landscape since medieval times. Between the 12 th and 14 th cent. AD, the present-day tidal flats around the marsh island Hallig Sudfall belonged to the historical Edomsharde district and its main settlement Rungholt . For North Frisia, it is well known that during medieval and early modern times, extreme storm surges caused major land losses associated with a massive landward shift of the coastline. Today, cultural traces like remains of dikes, drainage ditches, terps or even…

Automated facies identification by Direct Push-based sensing methods (CPT, HPT) and multivariate linear discriminant analysis to decipher geomorphological changes and storm surge impact on a medieval coastal landscape

In ad 1362, a major storm surge drowned wide areas of cultivated medieval marshland along the north‐western coast of Germany and turned them into tidal flats. This study presents a new methodological approach for the reconstruction of changing coastal landscapes developed from a study site in the Wadden Sea of North Frisia. Initially, we deciphered long‐term as well as event‐related short‐term geomorphological changes, using a geoscientific standard approach of vibracoring, analyses of sedimentary, geochemical and microfaunal palaeoenvironmental parameters and radiocarbon dating. In a next step, Direct Push (DP)‐based Cone Penetration Testing (CPT) and the Hydraulic Profiling Tool (HPT) wer…

The Mycenaean drainage works of north Kopais, Greece: a new project incorporating surface surveys, geophysical research and excavation

The attempt to drain the Kopais Lake was one of the most impressive and ambitious technical works of prehistoric times in Greece, inspiring myths and traditions referring to its construction and operation. The impressive remnants of the Mycenaean hydraulic works represent the most important land reclamation effort during prehistoric Greek antiquity, thus attracting the attention of the international scientific community. Nevertheless, in spite of the minor or extended contemporary surveys, the picture of the prehistoric drainage works in Kopais has remained ambiguous. Concerning the function of these works and their precise date within the Bronze Age, the proposed theories were based solely…

TERRESTRIAL LASER SCANNING FOR COASTAL GEOMORPHOLOGIC RESEARCH IN WESTERN GREECE

We used terrestrial laser scanning (TLS) for (i) accurate volume estimations of dislocated boulders moved by high-energy impacts and for (ii) monitoring of annual coastal changes. In this contribution, we present three selected sites in Western Greece that were surveyed during a time span of four years (2008-2011). The Riegl LMS-Z420i laser scanner was used in combination with a precise DGPS system (Topcon HiPer Pro). Each scan position and a further target were recorded for georeferencing and merging of the point clouds. For the annual detection of changes, reference points for the base station of the DGPS system were marked. Our studies show that TLS is capable to accurately estimate volu…

Sedimentological and geoarchaeological evidence of multiple tsunamigenic imprint on the Bay of Palairos-Pogonia (Akarnania, NW Greece)

Abstract This paper presents evidence of multiple tsunami impact on the Bay of Palairos-Pogonia, NW Greece, during the Holocene based on detailed geo-scientific studies. Altogether, 41 vibracores were drilled to detect high-energy influence in the stratigraphical record. Layers of coarse-grained allochthonous marine deposits were found intersecting autochthonous fine-grained back beach sediments in the Palairos coastal plain, on top of beach or marly bedrock units at Pogonia beach and along the Pogonia cliff section. High-energy deposits are associated with specific sedimentary structures such as fining upward sequences, rip up-clasts, basal erosional contact, bi- to multimodal grain size d…

Potential and limits of combining studies of coarse- and fine-grained sediments for the coastal event history of a Caribbean carbonate environment

The coastal deposits of Bonaire, Leeward Antilles, are among the most studied archives for extreme-wave events (EWEs) in the Caribbean. Here we present more than 400 electron spin resonance (ESR) and radiocarbon data on coarse-clast deposits from Bonaire’s eastern and western coasts. The chronological data are compared to the occurrence and age of fine-grained extreme-wave deposits detected in lagoons and floodplains. Both approaches are aimed at the identification of EWEs, the differentiation between extraordinary storms and tsunamis, improving reconstructions of the coastal evolution, and establishing a geochronological framework for the events. Although the combination of different metho…