Morphological data and definition of tsunamigenic areas between Apulia (Italy) and Ionian Islands (Greece)

The investigated coastal sector is characterized by morphological evidence of palaeotsunami impact. Some of these palaeotsunamis, constrained by morphological surveys, absolute dating and historical investigations, show a good time correlation with strong earthquakes characterised by epicentres located in the eastern part of the Adriatic Sea. Here we present the results of new morphological studies carried out along the coasts of Montenegro, Albania and Greece, which improved the knowledge of the tectonic behaviour of this part of Adria. In particular, the coasts of the Kerkira Island (Corfù) show abundant evidence of relevant coseismic uplift occurred about 3.0-3.5 ka BP and more recently (uncalibrated age). Sedimentological and morphological studies carried out on and near the Lefkada Island allowed the identification of different tsunami events occurred 3.0-3.5 ka BP and more recently. Finally, ridges of megaboulders have been identified along the Ionian coast of Salento between Otranto and Leuca, and they have been ascribed to the strong (M 6.9) earthquake occurred on February 20th, 1743 with epicentre generically located in the Ionian Sea between the Ionian Islands and Salento. All these data suggest that many of the tsunamis affecting southern Adria could have been generated to the south of the Otranto Straits, possibly near the Kerkira and Lefkada Islands. Due to the overall geodynamic setting of the region and considering the particular high potential associated with reverse faults cutting the sea bottom, the most likely tsunamigenic structures, possibly causative of the observed coastal effects, can be associated with the still active collision between Adria and the External Hellenides