The Kefalonia Fault, also called the Kefalonia Transform Fault Zone, runs offshore along the western edge of the Ionian Islands in Greece. It is a right-lateral strike-slip boundary that accommodates the transition between subduction of the African Plate to the south and the continental collision of the Hellenic Arc to the north, making it one of the most seismically active spots in Europe.
The fault marks a sharp change in crustal behaviour, and the islands of Kefalonia and Lefkada sit directly astride it. High slip rates concentrate energy into frequent moderate-to-strong earthquakes, and the local geology and building stock make the islands especially vulnerable to repeated damaging shocks.
The catastrophic 1953 Ionian earthquake sequence (with a main shock near magnitude 7.2) levelled most towns on Kefalonia and Zakynthos, forcing mass reconstruction and emigration. More recently, twin magnitude-6 earthquakes struck Kefalonia in early 2014, and the 2015 Lefkada quake caused fatalities and landslides, confirming the fault's continued threat.