Santorini, the popular Greek holiday island, is taking emergency measures in response to intense seismic activity

Schools remain shut and evacuation flights are underway as Greek holiday island Santorini was rattled by earthquakes for the fourth day in a row. A spike in seismic activity has been recorded on the volcanic island in the Aegean Sea since Friday,

The strongest earthquake recorded was magnitude 4.6 at 3:55 p.m. Sunday, at a depth of 14 kilometers (9 miles), the Athens Geodynamic Institute said.