Greece has declared a state of emergency on the island of Santorini due to frequent earthquakes, some with magnitudes above 4.0. The “earthquake swarm” is affecting nearby islands in the Aegean Sea and has been ongoing since late January.
Seismologists say the activity is likely an earthquake swarm, characterized by multiple small earthquakes over days or weeks, rather than a mainshock- aftershock sequence with a single large event. The region’s unique geology, near the Hellenic subduction zone, makes it prone to seismic activity.
Local scientists have reported no signs of a Santorini eruption imminent, and the swarms can be less dramatic than strong mainshocks. However, seismologists are monitoring the situation closely, as a larger earthquake is still possible.
The current swarm has seen thousands of earthquakes with magnitudes between 4.0 and 5.0, and has caused minor damage to buildings and rock falls along coastal cliffs. The largest earthquake recorded was magnitude 5.1 on February 6, felt in Athens and parts of Turkey.
Santorini is now largely empty due to fears of a potential volcanic eruption, with over 11,000 people leaving the island in the past week. Earthquake swarms can persist for months or slow down and intensify again, causing intermittent ground shaking.
Source: https://www.sciencealert.com/earthquake-swarm-emergency-in-santorini-after-thousands-of-quakes