Tsunami hazard in the Eastern Mediterranean: geological evidence from the Anatolian coastal area (Silifke, southern Turkey)

Abstract

Tsunami deposits are used worldwide to provide a record of past offshore earthquakes and submarine landslides, which is essential for tsunami hazard evaluation. This work shows for the first time geological evidence of tsunamis along the coast of southern central Turkey. The occurrence of onshore, m-scale out-of-place boulders at 2.6 m a.s.l. in the Silifke district (southern Anatolia) is here interpreted as transported by tsunami waves with a minimum run-up of 3.0 m. AMS 14C dating on vermetids (Bivonia triquetra) from those boulders point to a tsunami event younger than 1950 AD. From the Eastern Mediterranean tsunami catalog, the only tsunamigenic event within the chronicles that is supposed to have impacted southern Anatolia after 1950 AD is the 10 September 1953 M = 6.2 earthquake, which resulted from activity along the SW Cyprus subduction zone and Paphos transform fault. However, given the low magnitude of the 10 September 1953 earthquake which could have been insufficient to generate a tsunami with minimum run-up of 3.0 m, a local tsunami triggered by a marine landslide from the southern margin of the southern Anatolia cannot be ruled out. Considering the proximity of earthquake tsunamigenic zones (e.g., Hellenic and Cyprean arc subduction zones) and the potential for local landslide-generated tsunamis, tsunami waves with run-ups higher than 3.0 m could be expected to have struck the southern Anatolian coast in the past and will likely strike in the future. Evidence for past tsunamis that affected the Mediterranean coast of southern Turkey has to be taken into account for tsunami risk assessment, particularly in areas where strategic infrastructure has been planned (e.g., Akkuyu Nuclear Power Plant).