Palaeoenvironmental evolution of the ancient harbor of Lechaion (Corinth Gulf, Greece): Were changes driven by human impacts and gradual coastal processes or catastrophic tsunamis?

The Corinth Gulf, Central Greece, is one of the most rapidly widening tectonic rifts on Earth, where large earthquakes with magnitudes of up 7.0 have been documented not only by instrumental records but also assessed from historical reports extending back to the 5th century BCE. Several of these earthquakes were associated with tsunamis, particularly in the western part of the Gulf. Of particular interest is the ancient harbor of Lechaion in the eastern side of Corinth Gulf. We reexamine the hypothesis that Lechaion was hit by high-energy tsunami waves in the 8th-6th century BCE, 1st-2nd century CE, and during the 6th century CE. On the basis of sedimentological, seismotectonic, archaeological and historical data, completed with field observations, we support that there is no evidence for tsunami impact in Lechaion. Local stratigraphy and environmental changes are rather interpreted by human impacts and gradual coastal processes. Such interpretations confirm that the tsunami potential in the east Corinth Gulf is relatively low.