Tsunami deposits on the coastline of west Crete (Greece)

The eastern Mediterranean and the Aegean Sea in particular, are the most active seismic regions in Europe. Historically, numerous earthquakes have occurred in this part of the world and comprehensive tsunami recordings exist. Nevertheless, field evidence of tsunamis is rare, although many neotectonic movements certainly must have triggered very strong tsunami waves. Along the coastlines of western Crete, we found evidence for tsunami impacts, such as 1) bimodal deposits (large clasts floating in sands comprised of shell fragments); 2) dislocation of large boulders with tilting of biogenous notches; and 3) boulders (with Lithophaga or Cliona borings) weighing up to 75 tons thrown onshore and imbedded in strata of marine shells. This paper documents these deposits and discusses whether they originated from the sudden uplift that occurred in 365 AD. Moreover, numerical radiocarbon ages reveal the occurrence of two tsunamis dated to 5660 yrs BP and 500 yrs BP. Evidence for other tsunami impacts is discussed, but not supported by numerical dating due to the lack of suitable material.