ATHENS, Greece — 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.

A seismologist from the European-Mediterranean Seismological Centre has said it may take “weeks” to see how the ongoing earthquakes disrupting Santorini and other Greek islands evolve, warning that the disruption seen so far could amount to foreshocks ahead of a larger quake.

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.