Earthquake swarm recorded in Campi Flegrei, Italy
An earthquake swarm began in the Campi Flegrei area of southern Italy at 08:03 LT (07:03 UTC) on February 5, 2025.
Seismic activity map of Campi Flegrei on February 5, 2025. Image credit: INGV
An earthquake swarm was detected at Campi Flegrei between 08:03 and 13:05 LT (07:03 and 12:05 UTC) on February 5, 2025. A total of 63 earthquakes were detected, with the highest magnitude event measured at 3.1 at a depth of 0.3 km (984 feet), according to the Italian National Institute of Geophysics and Volcanology (INGV).
The earthquakes are concentrated within the Campi Flegrei, a large volcanic area west of Naples. The events vary in depth with the shallowest recorded at 0.1 km (328 feet) and the deepest reaching 4.4 km (2.7 miles).
The total number of localized earthquakes in the Campi Flegrei region for the year 2025 has now reached 449.
The Campi Flegrei area has been experiencing increased seismic activity in recent years, with scientists closely monitoring potential geophysical changes. Further analysis will determine if the swarm is linked to ongoing subsurface magmatic processes or tectonic adjustments within the caldera.
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The Campanian volcanoes, Vesuvius, Campi Flegrei, and the island of Ischia, represent the most monitored and studied volcanic areas in the world because of the risk associated with a possible resumption of volcanic activity.
The ongoing swarm adds to the long history of seismic activity in the Campi Flegrei which is a 13 km (8 miles) wide volcanic complex. It encompasses Naples and extends south into the Gulf of Pozzuoli.
The region’s geology is marked by extensive ground deformation, fumarolic activity, and seismicity because of the underlying magmatic and hydrothermal systems.
Campi Flegrei has experienced cycles of uplift and subsidence since Roman times. Its earliest known volcanic products date back approximately 47 000 years.
The caldera was formed after two major explosive eruptions, the Campanian Ignimbrite eruption about 36 000 years ago and the Neapolitan Yellow Tuff (NYT) eruption around 15 000 years ago, which ejected over 40 km3 (9.6 mi3) of material.
After the NYT eruption, numerous smaller eruptions occurred from scattered vents both on land and underwater. Most activity was concentrated in three periods: 15 000 – 9 500 years ago, 8 600 – 8 200 years ago, and 4 800 – 3 800 years ago.
The most recent eruptions were recorded in 1158 CE at Solfatara and in 1538 CE (VEI 3) when the Monte Nuovo cinder cone was formed.
Update
February 6
The earthquake swarm was officially declared over at 21:47 UTC on February 5. In total, 78 seismic events were recorded, with magnitudes ranging from 0.0 to a maximum of Md 3.1 ± 0.3.
The updated seismic data indicate that the swarm consisted of low-to-moderate magnitude earthquakes, with depths varying from 0.1 km (328 feet) to 4.4 km (2.7 miles).
References:
1 Campi Flegrei earthquake swarm – INGV – Accessed on February 5, 2025
2 Campi Flegrei – GVP – Accessed on January 13, 2025
Rishika holds a Master’s in International Studies from Stella Maris College, Chennai, India, where she earned a gold medal, and an MCA from the University of Mysore, Karnataka, India. Previously, she served as a Research Assistant at the National Institute of Advanced Studies, Indian Institute of Science, Bengaluru, India. During her tenure, she contributed as a Junior Writer for Europe Monitor on the Global Politics website and as an Assistant Editor for The World This Week. Her work has also been published in The Hindu newspaper, showing her expertise in global affairs. Rishika is also a recipient of the Women Empowerment Award at the district level in Haryana, India, in 2022.
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