Event #2646: Tsunami drowns Persian army ending siege of Potidea, model for Exodus story

But when Artabazus¹ had besieged Potidaea for three months, there was a great ebb-tide in the sea, lasting for a long while, and when the foreigners saw that the sea was turned to a marsh they made to pass over it into Pallene. But when they had made their way over two fifths of it and three yet remained to cross ere they could be in Pallene, there came a great flood-tide, higher, as the people of the place say, than any one of the many that had been before ; and some of them that knew not how to swim were drowned, and those that knew were slain by the Potidaeans, who came among them in boats. The Potidaeans say that the cause of the high sea and flood and the Persian disaster lay herein, that those same Persians who now perished in the sea had profaned the temple and the image of Poseidon that was in the suburb of the city; and I think that in saying that this was the cause they say rightly. They that escaped alive were led away by Artabazus to Mardonius² in Thessaly. Thus fared these men, who had been the king’s escort.

After the battle of Salamis, the city of Potidaea revolted and Artazabus I of Phrygia, a satrap of Xerxes, was responsible for suppressing it. In front of this dangerous revolt, which might inspire others, Artazabus acted promptly and besieged Potidaea. The city survived all Artazabus’ attempts to take it, and the siege dragged on for three months (December 480 to 29 March 479). However, an opportunity appeared, in the shape of an exceptional low tide (the tidal rise and fall as rule in the Aegean amounts to only a few inches), which left a wide belt of sea-bottom and shallows exposed at the end of the wall of Potidaea. The sea showed no sign of coming back, and Artazabus with a prompt opportunism ordered his troops to go through. But when they were nearly half-way, the sea did come back, in an exceptional flood. According to Burn¹, the whole phenomenon was caused by an undersea-earth tremor, and could be the first description of a historical tsunami.

A study published in 2010 describes possible tsunami sediment deposits in Thermaikos Gulf that could be attributed to that historical event². In another study two years later and presented at the annual meeting of the Seismological Society of America in San Diego, Reicherter et al. found during the excavation of the proasteion at the ancient city of Mende on the Possidi peninsula of Kassandra, a high-energy layer containing a vast amount of ceramics along with shells of Acanthocardia sp dated to 500 BC. More evidence has been found on the Possidi penisula where the researchers drilled shallow cores (up to 10 m) and found sedimentary evidence for high-energy events³