Palaeotsunami history of the Elos Plain (Evrotas River delta, Peloponnese, Greece)
Ntageretzis, Konstantin; Vött, Andreas; Fischer, Peter; Hadler, Hanna; Emde, Kurt; Röbke, Björn Roman; Willershäuser, Timo
published: Dec 1, 2015
Central Lakonia is directly exposed to the Hellenic Trench, one of Europe's most seismically active and tsunamigenic regions. Aside from historical accounts on past tsunami events the aim of this study was to search for geomorphological and sedimentological traces of palaeotsunamis in near-coast geological archives. Based on geophysical surveys, systematic stratigraphical studies were carried out in the Elos Plain in the Evrotas River delta using a multi-proxy approach. Palaeotsunami signatures were searched along two south-north running vibracore transects. Our methodological approach comprised sedimentological, geomorphological, geochemical, geochronological, microfaunal and geophysical investigations. We identified three allochthonous marine-borne sediment layers intersecting autochthonous limniclagoonal deposits over a distance of up to two kilometers. These intersecting sheets out of allochthonous marine sand document repeated tsunami landfall in the Elos Plain. The oldest tsunami signature encountered in the Elos Plain (T1) was radiocarbon dated to the time shortly after approximately 4400 cal BC. A second event occurred between approximately 1300 cal BC and 850 cal BC (T2), and a third one was dated to the time shortly before approximately 1450 cal AD (T3). The youngest event (T3) is a reasonable candidate for the historically known tsunami that occurred in 1303 AD associated to a strong earthquake. Events T1 and T2 occurred during prehistoric times; compa- rable findings in terms of sedimentary, geochemical and geochronological fingerprints are known from the Ionian Islands, northwestern Akarnania and the northwestern Peloponnese which allows to conclude that these events were of supra-regional nature.