The hundreds of earthquakes that have rattled Greek islands on the Aegean Sea are a “seismic swarm” and could continue for weeks before eventually diminishing, the Santorini mayor told The Associated Press on Tuesday — pausing to chuckle as new tremors shook items on his desk.

Hundreds of quakes have been registered in recent days in the Aegean Sea between Santorini and Amorgos, prompting authorities to shut schools and the islands of Ios, Amorgos and Anafi.