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

Santorini's earthquakes are intensifying as a rare earthquake swarm continues to rattle the Mediterranean's Aegean Sea. The earthquakes are probably caused by faults rather than volcanic activity.

Multiple earthquakes are rattling Santorini, a volcanic island in Greece, prompting authorities to dispatch rescuers with tents, a sniffer dog and drones, and to shut schools on four islands. Residents have been warned to avoid indoor gatherings,