The 8.5+ magnitude, AD365 earthquake in Crete: Coastal uplift, topography changes, archaeological and historical signature

Abstract

An up to 9 m uplift of western Crete, a cluster of coastal uplifts in the East Mediterranean radiocarbon dated approximately ∼1500 BP, as well as historical and archaeological data are evidence for major, although poorly documented seismic destruction on a nearly-Mediterranean scale in the 4th to 5th c. AD, including the destruction of the Nile Delta in Egypt by a tsunami in AD365. These data represent parts of a puzzle for historians, archaeologists, geologists and seismologists. Detailed analysis of geological, historical and archaeological data, including precise numismatic evidence, permits recognition of a major earthquake in Crete responsible for coastal uplift at AD365. Elastic dislocation analysis of coastal uplift data reveals that this earthquake was associated with a reverse fault offshore of southwestern Crete, that its minimum magnitude was 8.5, and that this model is consistent with the available seismological and large-scale tectonic data. Despite its magnitude, this earthquake cannot have produced the necessary short-period, high-energy waves which are necessary to explain the seismic damage which occurred circa AD365 in a very broad region, from Sicily to Cyprus and Libya. Hence, the AD365 earthquake sequence included at least two other major events, with epicentres close to Cyprus and Sicily. Although significant changes in the coastal morphology, widespread destruction, and a high human death toll occurred, the AD365 Crete earthquake was not responsible for any major cultural change. It occurred during the transition from the Roman to the Christian period, characterized by vast, luxurious villas and modest dwellings on Crete, respectively.