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.

Repeated earthquakes are rattling Greece’s volcanic island of Santorini. The quakes are prompting authorities to dispatch rescuers with tents, a sniffer dog and drones and to shut down schools on four islands.

Hundreds of people scrambled to leave the Greek island of Santorini by ferry Monday after an increase in seismic activity raised concerns about a potential powerful earthquake. (AP Video by Lefteris P