Black Sea Tsunamis and Paleotsunami Studies on the Thrace Coasts of Turkey

Abstract

It is identified that 23 moderate tsunamis hit the Black Sea's coasts during the last 2000 years. Some of these tsunamis had been catastrophic at some vulnerable spots of the coast, flooding coastal areas and drowning a few thousand people in towns and villages; such as the ones in 544/545 and 1598. Tsunamis may leave their fingerprints typically in low-energy depositional environments such as coastal wetlands, lagoons and places protected from the sea by sandy barriers. Such places protect tsunami deposits from post-depositional erosion. The topographic conditions of the Black Sea coastline of Turkey are not favourable in preservation of marine flood deposits. A few low lying beaches or marsh-filled depositional sedimentary basins on the Thrace coasts may have geomorphologic potential, even usually intercalated with fluvial effects of nearby creeks, to record and keep the clues of historical tsunami impacts. Yet there have been relatively few studies of the processes associated with tsunami sediment transport, their deposition and nature; the present study attempts to understand if a coarse grained sedimentary unit mixed with marine shell fragments observed in a trench in Kiyikoy could have been related to a historical tsunami. The soil samples were tested for their particle characterization, micro-fossil contents, standard sediment chemistry and biochemical conditions. Even though some effects of a marine intrusion were observed, the results are open to debate. For more meaningful regional explanations and to give way to numerical modelling which make the main tasks for tsunami hunting in the Black Sea, similar studies throughout the basin are needed.