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.

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

Thousands of locals and travelers have evacuated the Greek island of Santorini amidst a spike in seismic activity.