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

Greece’s government declared a state of emergency on Santorini on Thursday after hundreds of undersea earthquakes shook the resort island for nearly a week. The ministry of civil protection’s announcement will provide authorities faster access to state resources.

A series of earthquakes near Santorini, Greece has prompted tourists to flee the area and the country to declare a state of emergency.