Earthquakes are still rattling Greece’s volcanic island of Santorini every few minutes as authorities bolster their emergency plans in case the hundreds of temblors in recent days are a harbinger of a larger quake to come.

Tourists continued to flee the Greek island of Santorini on Wednesday — a fourth consecutive day of exodus sparked by a series of earthquakes that have rattled the incredibly popular European vacation destination.

Authorities have halted construction, closed schools, and ordered pools to be emptied as people flee Santorini amid ongoing seismic activity.