Schools on four Greek islands will remain closed next week as a series of earthquakes continue to shake the region, authorities said on Saturday. Santorini, Amorgos, Anafi, and Ios have experienced more than 800 tremors measuring magnitude 3 or higher since 1 February.

The last time Kolumbo experienced a major eruption was 1650, coughing out ash seen as far away as Turkey. Pyroclastic flows – fast-moving, searingly hot clouds of volcanic ash and gases – killed 70 people.