Olympia’s Harbour Site Pheia (Elis, Western Peloponnese, Greece) Destroyed by Tsunami Impact

Abstract

It is well known from historic catalogues that the Greek coast has repeatedly been struck by large earthquakes and associated tsunami events during the past millennia. The seismically highly active Hellenic Arc, where the African plate is being subducted by the Aegean microplate, is considered to be the most significant tsunami source in the wider region. The study presented in this paper focuses on sedimentary and geomorphological tsunami traces encountered at Pheia, western Peloponnese (Greece), one of the harbours of the nearby cult site Olympia. Sedimentological, pedological, geoarchaeological and geochemical analyses revealed tsunami sand and gravel of mostly marine origin reaching far inland. Wave refraction and channeling effects seem to have steepened tsunami waters up to 18-20 m above present sea level and induced tsunami water passage across the narrow Katakolo Pass into adjacent coastal plains. Tsunami deposits that were accumulated onshore were partly cemented and later exposed in the form of beachrock. By radiocarbon dating and archaeological age estimation of ceramic fragments, three distinct tsunami events were found, namely for the 6th millennium BC, for the time around 4300 ± 200 cal BC and for the Byzantine to post-Byzantine period. Olympia’s harbour site Pheia was finally destroyed by tsunami landfall, most probably in the 6th century AD and accompanied by co-seismic submergence.