The 7.2 Ms Ionian earthquake shakes the southern Ionian Islands with a maximum Mercalli intensity of X (Extreme). Between 445 and 800 people were killed.

The 1953 Ionian earthquake (also known as the Great Kefalonia earthquake) struck the southern Ionian Islands in Greece on August 12. In mid-August, there were over 113 recorded earthquakes in the region between Kefalonia and Zakynthos, and the most destructive was the August 12 earthquake. The event measured 6.8 on the moment magnitude scale, raised the whole island of Kefalonia by 60 cm (24 in), and caused widespread damage throughout the islands of Kefalonia and Zakynthos. The maximum felt intensity of shaking was X (extreme) on the Mercalli intensity scale. Between 445 and 800 people were killed.