🌋VolcanoAtlas

Campi Flegrei

Europe's Supervolcano Beneath Naples

Elevation

458 m

Last Eruption

1538

Type

Caldera

Country

Italy

Location

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Volcanic Hazards & Risk Assessment

Primary Hazards

  • Pyroclastic flows and surges
  • Large explosive eruptions (VEI 4+)
  • Ash fall and tephra deposits
  • Lahars and debris flows

Risk Level

Population at RiskHigh
Infrastructure RiskModerate
Aviation RiskSignificant

Geological Composition & Structure

Rock Types

Primary
Unknown
Silica Content
Varied composition

Tectonic Setting

Unknown
Intraplate setting with hotspot or regional volcanic activity.

Age & Formation

Epoch
Unknown
Evidence
Unknown

Eruption Statistics & Analysis

MetricValueGlobal RankingSignificance
Total Recorded EruptionsUnknownLowModerately active volcano
Maximum VEIVEI UnknownMinorLocal impact potential
Recent Activity488 years agoHistoricalHistorically active

Monitoring & Alert Status

Monitoring Networks

INGV Observatory
National Institute of Geophysics
Global Volcanism Program
International eruption database

Current Status

Normal
No recent activity. Routine monitoring continues.

Authority Sources

Smithsonian GVP
Official volcano database

Related Volcanoes

All Italy Volcanoes
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Caldera Volcanoes
By volcano type
Campania
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Interesting Facts

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The Campanian Ignimbrite eruption (~36,000 BP) ejected an estimated 200–300 km³ of material, making it the largest volcanic eruption in Europe during the past 200,000 years.

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Approximately 1.5 million people live directly within the Campi Flegrei caldera — most are unaware they inhabit an active volcanic system because the caldera has no prominent cone.

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The so-called 'Temple of Serapis' in Pozzuoli (actually a Roman marketplace) has columns bored by marine bivalves up to 7 m above their bases, providing a 2,000-year record of bradyseismic uplift and subsidence.

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Monte Nuovo, formed during the 1538 eruption, is the newest mountain in Europe — it grew to 130 m in just eight days.

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Since 2005, the center of Pozzuoli has risen by more than 1.1 m due to bradyseismic uplift, with acceleration to over 15 mm per month in 2023–2024.

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Lake Avernus, a flooded maar crater within the caldera, was identified by Virgil in the Aeneid as the entrance to the underworld — its name derives from the Greek áornos ('without birds'), supposedly because volcanic fumes killed birds flying over it.

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The Flavian Amphitheatre in Pozzuoli is the third-largest Roman amphitheatre ever built (after the Colosseum and Capua), and its underground chambers are among the best-preserved of any ancient arena.

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A magnitude 4.4 earthquake struck Campi Flegrei on May 20, 2024 — the strongest seismic event recorded at the caldera in more than 40 years.

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The Campanian Ignimbrite eruption has been hypothesized as a contributing factor in the extinction of Neanderthals in Europe, though this remains scientifically debated.

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Campi Flegrei and Vesuvius are just 15 km apart and monitored by the same observatory — together they create one of the most volcanically hazardous regions on Earth, threatening over 3 million people.

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In 2017, three members of a family (including an 11-year-old boy) died from volcanic gas inhalation after falling into a fumarolic pit at the Solfatara crater, leading to the closure of the site to tourists.

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Some of the submerged Roman ruins at Baia — including mosaics, statues, and villa foundations — lie 5–15 m below current sea level due to centuries of bradyseismic subsidence, creating an underwater archaeological park.

Frequently Asked Questions

Is Campi Flegrei a supervolcano?
Campi Flegrei is widely classified as a supervolcano based on its demonstrated ability to produce VEI 7 eruptions. The Campanian Ignimbrite eruption approximately 36,000 years ago ejected 200–300 km³ of material — meeting or exceeding the threshold (>450 km³ of deposits) commonly used to define 'super-eruptions.' The Neapolitan Yellow Tuff eruption ~15,000 years ago ejected over 40 km³. While the term 'supervolcano' is not a formal geological classification, Campi Flegrei is regularly listed alongside Yellowstone, Toba, and Taupo among the world's most significant caldera systems capable of producing civilization-threatening eruptions.
Is Campi Flegrei going to erupt?
Campi Flegrei is currently experiencing significant volcanic unrest — ground uplift exceeding 1.1 m since 2005, accelerating seismicity (including a magnitude 4.4 earthquake in May 2024), and rising temperatures in fumarolic fields. However, scientists emphasize that unrest does not necessarily lead to eruption. The caldera has experienced similar bradyseismic episodes in the past (notably 1969–1972 and 1982–1984) that subsided without eruption. Current monitoring data is being closely analyzed by INGV (Italy's National Institute of Geophysics and Volcanology), and the alert level stands at Yellow (Attention). The probability of eruption cannot be precisely quantified, but Italian authorities have updated evacuation plans as a precaution.
What is bradyseism at Campi Flegrei?
Bradyseism (from the Greek bradys, meaning 'slow,' and seismos, meaning 'movement') is the gradual uplift or subsidence of the ground surface caused by changes in pressure within a volcanic system's shallow magma chamber or hydrothermal reservoir. At Campi Flegrei, bradyseism has been occurring for millennia — Roman-era structures show evidence of both submersion and re-emergence. The modern bradyseismic crisis began in 2005, with the center of Pozzuoli rising over 1.1 m. The uplift is accompanied by earthquakes, increased fumarolic gas output, and structural damage to buildings. Whether the current episode is driven by fresh magma intrusion or heating of the hydrothermal system remains an active area of scientific research.
When did Campi Flegrei last erupt?
Campi Flegrei last erupted from September 29 to approximately October 6, 1538, in a VEI 3 event that created Monte Nuovo — a 130-m-tall cinder cone on the western shore of Lake Avernus. The eruption destroyed the village of Tripergole and killed approximately 24 people. It was preceded by years of notable ground uplift. The current repose period of nearly 500 years is the longest in Campi Flegrei's post-caldera history, which has led some volcanologists to suggest that the next eruption, when it comes, could involve a significant volume of accumulated magma.
How many people live on Campi Flegrei?
Approximately 1.5 million people live within the Campi Flegrei caldera and its immediate surroundings, including the cities of Pozzuoli (approximately 80,000), parts of western Naples, and the municipalities of Bacoli, Monte di Procida, Quarto, and Marano di Napoli. The 'zona rossa' (red zone) — the area at highest risk from pyroclastic flows in the event of an eruption — encompasses roughly 500,000 residents. The broader Naples metropolitan area, which could be affected by tephra fall and ashfall, is home to approximately 3 million people, making the Campi Flegrei–Vesuvius complex the most volcanically exposed urban region in Europe.
What would happen if Campi Flegrei erupted?
The impact would depend on the eruption's magnitude. A small eruption (VEI 2–3, similar to Monte Nuovo in 1538) would likely be localized, requiring evacuation of nearby communities and potentially affecting Pozzuoli. A moderate eruption (VEI 4–5, comparable to the Agnano Monte Spina event) could generate pyroclastic flows reaching densely populated areas within minutes, require evacuation of 500,000+ people from the red zone, and deposit ash across Naples. A worst-case VEI 7 super-eruption (like the Campanian Ignimbrite) would be a global catastrophe — devastating hundreds of square kilometers, collapsing European aviation, and inducing years of climate cooling. Current evacuation plans focus on VEI 4–5 scenarios as the most plausible high-impact outcome.
Can you visit Campi Flegrei?
Yes, Campi Flegrei is a fascinating destination accessible from Naples via the Cumana railway line or the Naples Metro Line 2. Notable sites include the Flavian Amphitheatre and Macellum (Temple of Serapis) in Pozzuoli, the volcanic crater lakes of Avernus and Agnano, the archaeological parks of Baia and Cumae, the Astroni nature reserve (inside a volcanic crater), and Monte Nuovo. The Solfatara crater, historically the most popular volcanic tourism site, has been closed since 2017 following fatal gas inhalation incidents, with reopening plans under discussion. The submerged Roman ruins at Baia can be viewed by glass-bottom boat or snorkeling tour. Spring and autumn offer the best visiting conditions.
Is Campi Flegrei more dangerous than Vesuvius?
Many volcanologists consider Campi Flegrei a greater long-term threat than Vesuvius because of its far larger caldera system, demonstrated capacity for VEI 7 super-eruptions, and the fact that more people live within its caldera boundaries. Vesuvius is capable of VEI 5 eruptions (like the one that destroyed Pompeii in 79 AD) but has never produced the continent-scale events recorded at Campi Flegrei. Additionally, because Campi Flegrei's vents can open at unpredictable locations across a 13-km-wide area, evacuation planning is more complex than for Vesuvius, which has a single well-defined cone. Both systems are monitored by the Osservatorio Vesuviano, and both pose extreme risk to the Naples region.