Residents on the popular island of Santorini have experienced thousands of earthquakes this month while researchers have revealed a new magma chamber growing underneath the Kolumbo submarine volcano.

Multiple earthquakes are rattling Santorini, a volcanic island in Greece, prompting authorities to dispatch rescuers with tents, a sniffer dog and drones, and to shut schools on four islands. Residents have been warned to avoid indoor gatherings,

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.