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.

In Fira, Santorini’s main town, local authorities have set up gathering points for residents though no evacuation orders are in place right now. However, it’s been agreed by seismologists that these quakes could be an indicator of an impending seismic event.

The Greek island of Santorini remains on high alert as earthquake tremors persist for the fourth consecutive day, prompting the authorities to close schools and arrange additional flights to facilitate evacuations.