The 373 BC Helike (Gulf of Corinth, Greece) Earthquake and Tsunami, Revisited

Ancient authors report the destruction and drowning in 373 B.C. in the Gulf of Corinth (Greece) of Helike (Helice and Eliki), an important, nearly coastal town, and of Boura (Bura, Buris, Bouris, and Voura), another town in the hinterland, as a punishment by the ancient God Poseidon because of a serious crime committed in his shrine. This narrative has been regarded as a description of a true event, though with some exaggerations, and the 373 B.C. event is included in earthquake and tsunami catalogs. In the first part of this article, it is shown that (1) local natural hazards exclude the possibility (risk) of total loss of the ancient "polis" (town state) of ancient Helike because of its vulnerability due to its geography. (2) Systematic geoarchaeological studies confirm this prediction because they reveal essentially undisturbed archaeological layers predating and postdating 373 B.C., with no signs of a tsunami. (3) Archaeological excavations have recently brought to light, among other findings, remains of the harbor of Boura and of the shrine of Poseidon at Helike, as well as coins issued by Helike several decades after its alleged loss. This evidence permits a reconsideration of ancient texts related to the loss of Helike in a supervised learning-type approach. It was found that genuine ancient Greek texts do not mention any catastrophe of Helike, but rather that the legend of its total loss appeared several centuries later in Roman times, in local legends, rumors, and forged or manipulated ancient texts (e.g., by pseudo-Aristotle). The ancient legend became important because it explained the collapse of the town state of Helike and it fit ancient religious ideas in a tectonically active region because of the rapid burial ("disappearance") of ancient Greek remains under sediments in a young delta and because of the prominent location of Helike in the seafaring route between Rome and the eastern Mediterranean. For earthquakes before our era, historical and archaeological data have attracted interpretations... attributing to earthquakes... the demise of flourishing city-states. ...The reason for the revival of catastrophe hypotheses is perhaps that they are easy to explain. They are too simple, too obvious and too coincidental and chiefly because they have become fashionable in recent years. (Ambraseys, 2006)