Seismic Swarms Strike Greece and Italy: Ongoing Earthquakes Raise Concerns

A series of powerful seismic events are shaking both Greece and Italy, raising concerns in regions known for volcanic activity. The most recent swarms are happening in two notable locations: the Aegean Sea between the islands of Santorini and Amorgos in Greece, and the Campi Flegrei volcanic caldera in southern Italy.

On February 18, 2025, two M5.1 earthquakes struck between the islands of Santorini and Amorgos. The quakes, recorded at a depth of 8 km, were part of an ongoing seismic swarm that began in late January. These tremors were the fourth strongest recorded in the series so far.

The seismic activity has led authorities to declare a state of emergency on multiple islands, including Santorini, Amorgos, Anafi, and the newly added Ios as of February 15. The state of emergency is set to remain in effect until March 14, 2025, while officials continue to assess the stability of the region. Despite fears of volcanic activity, seismologists such as Dimitris Papanikolaou and Kostas Papazachos have dismissed concerns about an impending eruption, affirming that while magma movement is detected at significant depths, the likelihood of an eruption is low.

In response to the ongoing tremors, Athens and Airbnb have launched a program offering temporary housing for displaced families from the affected islands, with covered costs for up to ten days. Additionally, Greece’s Minister of Climate Crisis and Civil Protection, Vassilis Kikilias, announced the construction of an emergency evacuation port on Santorini, developed in collaboration with the Greek Armed Forces, to facilitate a swift evacuation of residents in the event of a major earthquake.

The recent seismic activity has also taken a toll on the local economy. Santorini, a top tourist destination, has seen economic losses as cruise lines reroute ships to alternative ports like Crete and Syros. The Greek government has promised financial aid for affected businesses while schools on the islands remain closed for safety.

Italy: Campi Flegrei Seismic Swarm Intensifies

In Italy, the Campi Flegrei volcanic caldera, located near Naples, has been experiencing its own seismic activity. Since February 15, 2025, the area has been rocked by more than 550 earthquakes, with magnitudes reaching up to M3.9. This intense swarm has prompted local authorities to close schools in the town of Pozzuoli, close to the epicenter, for safety inspections.

The ongoing swarm is linked to a phenomenon called bradyseism, where the ground rises or falls due to underground magma or hydrothermal activity. While this is not an unprecedented event, the scale of the swarm and the region's history of volcanic eruptions has led to concerns. Campi Flegrei has a long history of seismicity and ground deformation, and while this current swarm is significant, it has not yet reached crisis levels similar to the 1982-1984 bradyseismic crisis, which led to the evacuation of 40,000 residents.

The Italian Civil Protection Department has deployed emergency responders and set up temporary shelters in Pozzuoli, Bacoli, and Naples. Nello Musumeci, Civil Protection Minister, has raised concerns about urban development in this seismically active region, and authorities are monitoring the situation closely.

What Lies Ahead

Both Greece and Italy are grappling with the effects of unusual seismic activity. In Greece, the continuing swarm between Santorini and Amorgos is causing significant disruptions to daily life, while in Italy, the Campi Flegrei caldera remains under close scrutiny for any signs of further escalation. Seismologists in both countries stress the importance of responsible communication to the public, as the situation develops.

In both regions, authorities and residents are on high alert, prepared for the possibility of more tremors or ground deformation in the coming weeks. For now, while the events remain significant, experts emphasize that full-scale eruptions or catastrophic events are not imminent.