June 426 BC Tsunami: Corinthos-Patras Gulf, Greece

Ref #2130:

426 BC Summer (possibly 425), 38.75 N, 22.75 E, earthquake magnitude 7.1, intensity XI, tsunami intensity v. Aegean Sea, eastern Greece. Island of Euboea, Gulf of Maliacus. Evidence provided by Thucidides indicates that a series of earthquakes occurred in the regions of Attica, Boeotia, Euboea in the autumn of 427 B.C. ... Several shocks in the summer and autumn of 426 B.C. occurred in the strait separating the Euboea Island from the continent.

According to eyewitness Demetrios Kallatianos, a significant part of the Lichades Island and the Cape Cenaeon sank under water. The shore near Orobies also sank and the coastal line shifted deep into dry land. The base of one of the peninsulas opposite the continental shore sank, and the Island of Atalanti appeared (Talantonissi).

After one of the earthquakes, the sea in Orobies retreated from the coastal line, but later on, coming back in the form of huge "swelling", it partly flooded the settlement and this was repeated many times. According to Strabo, the waves flooded the shore three times, penetrating the continental coast of Greece 3-4 miles inland. Gullies in the vicinity of Tarfi, Thronium, Thermoplyles and Daphus were flooded, and many settlements were destroyed. A similar flood took place on the Atalanti Island: here, waves caught up triremes and dragged them along the shore for more than 2 miles; another trireme was torn away from a moorage and smashed against the walls. The sea also retreated from the coast in Peparithos and Skopelos, too, but no flood accompanied this process. The wave was observed in Opus near Kiparissi. On the eastern shore of Euboea Island no waves were observed. Judging from descriptions, a tectonic collapse occurred in the strait between the Euboea Island and the continent, resulting in great seiches. One must agree with Antonopoulos that possible local landslides of friable material were not the main cause of variations in the water level in the strait.

Ref #4139:

426 BC June, earthquake magnitude 7.1, intensity X, 38 deg 54 min N, 22 deg 42 min E, tsunami intensity v, event validity 4. This is one of the most disastrous earthquakes recorded in ancient sources. The shock occurred in the Isthmus of Corinth area and particularly in the city of Orobiae in NW Euboea. Buildings collapsing, destruction caused by seismic sea waves and thousand of victims. Profound hydro-geological disturbances reported. Permanent changes in the shoreline. Extensive seismic sea wave affecting Orobiae, the Island of Atalante and the Aegean island of Paparethus. At the time of the earthquake the sea at Orobiae receded from the shoreline, then a great sea wave engulfed part of the city. Many people perished. A similar flood occurred at the island of Atalante carrying away part of the Athenian fort and wrecked one of two ships which had been drawn up on the shore. The sea also receded at Paparenthus but there was no flood.

Ref #9116:

426 BC October, Maliac Gulf. A destructive earthquake in central Greece. According to Thucydides and Demosthenes it occurred during the celebration of the Thesmophotia (October/November) in the Athenian calendar), in the sixth year of the Peloponesian War (426 BC). Much of the destruction caused by the earthquake and the associated seismic sea wave occurred on both sides of the coasts of the Euboean, Maliac and Oreus Gulfs.

Ref #109:

A destructive shock in the Gulf Maliakos and on the island Euboea, with large effects on terrain, was followed by three devastating tsunamis. They say, the waves overwhelmed Orobiae (now Roviae), swept clean the island Atalanti (now Talantonisi), and entered in Opous (near Kyparissi) a half mile inland.