Static stress changes and fault interactions in Lefkada Island, Western Greece

The complicated tectonics of the Mediterranean region, dominated by the subduction of the African plate under Eurasia, affects the whole of Greece. A significant extension rate across the Aegean sea is estimated from satellite geodetic observations, while intense seismicity is observed in parts of the Hellenic arc, manifested by strong earthquakes (Ms > 6) of intermediate depth that take place along it.In Western Greece, the Ionian Islands are situated in a transitional zone (from the Hellenic subduction to the Adriatic collision), characterised by a high crustal deformation rate as revealed by the high seismicity of this zone, the highest in Greece, and the GPS velocity field estimated for the region. In this part of the Aegean plate, transcurrent fault systems dominate, one of which is the Kephalonia Transform Fault (KTF), located offshore the Kephalonia and Lefkada Islands, with a right-lateral slip of the order of 3 cm/year.In the present work an attempt is made to assess the Coulomb stress change associated with well documented earthquake activity, from 1973 to 2003, in the Ionian Island of Lefkada. The results of this study suggest that the early 1973 event did not influence any subsequent moderate earthquakes in the area. On the other hand, the 1994 earthquake may have triggered the north segment of the 2003 event, while the 2003 earthquake ruptured two segments with the north one initiating rupture on the south segment.