Santorini has been hit by a powerful, shallow 5.3 magnitude earthquake, which is the strongest to strike the Greek island during recent seismic activity in the area. The tremors were felt in Athens on Monday evening and measured a focal depth of 17km (10.6 miles).

The Greek island has a long history of earthquakes, but what is causing the recent series of quakes has scientists perplexed.

A state of emergency has been declred in Santorini, a volcanic island and popular tourist destination in Greece, as an 'earthquake swarm' that began earlier this month continues. Since 31 January, more than 800 tremors with a magnitude of three and above have been recorded.

Greek islands continue to shake as experts fear stronger earthquakes - The activity has led to a significant exodus of residents and tourists