In a quiet stretch of land just outside Naples, Italy, a slumbering colossus is stirring—and its restlessness is starting to unsettle those who study the inner workings of our planet. Campi Flegrei, a vast and ancient supervolcano, has been making headlines once again as scientists report a dramatic uptick in seismic activity and gas emissions that could signal a brewing eruption.
A Shaky Situation: Earthquakes Raise the Stakes
It all began, quite literally, with a jolt. In May, the region around Campi Flegrei also known as the Phlegraean Fields was rocked by a magnitude 4.4 earthquake, the strongest tremor to strike the area in four decades. But that was just one in a relentless series of over 3,000 smaller quakes recorded over the past six months.
For volcanologists, such a seismic swarm is more than just geological noise. These tremors, known as microquakes or tremors, may indicate that pressure is building up deep below the surface. In many volcanic systems, increased shaking often precedes eruptions. It’s the Earth’s way of signaling that something is shifting underground.
Think of Campi Flegrei like a pressure cooker: over time, steam builds beneath the lid. The more steam, the more strain on the seal. Eventually, something has to give. In the case of a supervolcano, that “give” could be catastrophic.
When Gas Becomes a Warning Sign
Aside from the shaking, another major red flag has caught scientists’ attention: a notable rise in volcanic gas emissions. Measurements from Italy’s National Institute of Geophysics and Volcanology (INGV) show daily carbon dioxide emissions ranging between 4,000 and 5,000 metric tons. That’s an enormous volume for a region that has, for centuries, remained largely inactive on the surface.
Gas releases from volcanic systems are often linked to magma rising closer to the Earth’s crust. As magma moves upward, it depressurizes and releases volatile gases, including carbon dioxide. This outgassing is not just a chemical curiosity—it’s a sign that magma is likely on the move.
According to scientists monitoring the situation, magma beneath Campi Flegrei is now just a few kilometers below ground. While that might sound like a comfortable buffer, it’s alarmingly shallow by volcanic standards.
Dr. Christopher R. J. Kilburn, a volcanologist working with INGV, emphasizes the importance of distinguishing between gases released by magma and those formed by hot water reacting with underground rock. Both are common in volcanic areas, but only one is a potential eruption precursor.
Read more: Trees Can Actually Warn Us When Volcanos Are Ready to Erupt
A City in the Crosshairs
More than four million people live in the shadow of Campi Flegrei, including the bustling city of Naples and nearby towns like Pozzuoli. These are not remote mountain villages; they are densely populated urban centers sitting atop an ancient caldera.
If the volcano were to erupt, the fallout could be catastrophic. Lava flows, ash plumes, and scalding pyroclastic surges could wipe out infrastructure, bury neighborhoods, and leave essential services like water and electricity in ruins.
It’s not just about molten rock. Volcanic ash can ground airplanes, destroy crops, clog engines, and cause respiratory distress. In worst-case scenarios, it can alter global weather patterns for years.
Authorities have not taken the threat lightly. In 2012, the official volcanic alert level for Campi Flegrei was raised from green (normal) to yellow (caution). Emergency evacuation protocols have been drafted and revised, but coordinating a mass movement of millions under sudden threat remains a logistical challenge of epic proportions.
The Science Behind the Concern
A team led by Gianmarco Buono, a doctoral researcher at the University of Naples Federico II, recently conducted a study analyzing gas emissions from Solfatara, one of the many volcanic vents within the Phlegraean Fields. Their findings are eye-opening: nearly 80% of the carbon dioxide in the area is directly linked to magma activity. The remaining 20% comes from interactions between hot fluids and subterranean rock, a less ominous phenomenon.
This study adds weight to the theory that magma is inching its way closer to the surface, creating mounting pressure beneath the Earth’s crust. Combined with swelling ground and persistent quakes, this trifecta of signals is cause for real concern.
One of the more intriguing tools in the scientists’ arsenal is a concept borrowed from engineering: mechanical failure modeling. Traditionally used to evaluate the stress and stability of man-made structures, this technique has been adapted to assess how rock layers behave under extreme subterranean forces.
According to recent analyses, the crust beneath Campi Flegrei is shifting from bending to cracking—a transition that often precedes volcanic eruptions. Cracks in the rock can act like escape hatches, allowing magma to surge upward more easily.
Read more: Scientists Once Drilled So Deep Into the Center of the Earth, They Knocked on the Mantle’s Door
What History Can Teach Us
To understand the potential scale of a Campi Flegrei eruption, we must look back—way back. Around 40,000 years ago, the supervolcano unleashed one of the most violent eruptions in Earth’s history. That event is believed to have triggered massive climate disruptions, possibly even accelerating the decline of Neanderthal populations in Europe.
Campi Flegrei’s last eruption, a relatively minor one, occurred in 1538. It created a new hill, Monte Nuovo, in just a few days. Since then, the volcano has remained superficially calm, but geologists have noted increasing unrest since the mid-20th century.
One ongoing phenomenon is known as bradyseism—a slow rising and sinking of the ground caused by underground shifts in magma and gas. In Pozzuoli, the ground has risen by nearly five feet since this latest phase began in 2005, a sure sign that things are shifting below.
This gentle lift might seem harmless, but it’s anything but. It’s like watching a balloon inflate slowly—you know it won’t stay that way forever.
A Global Domino Effect
Though located in Italy, an eruption of Campi Flegrei could have worldwide repercussions. Volcanic ash released into the upper atmosphere can travel vast distances, potentially covering parts of Europe in a thick, suffocating haze.
Beyond the local devastation, such an eruption could disrupt international air traffic, destroy agricultural production across regions, and cause longer-term atmospheric changes. A sufficiently powerful blast might release enough sulfur and ash to reduce global temperatures, akin to what occurred after the 1815 eruption of Mount Tambora in Indonesia—a disaster that led to the “Year Without a Summer” in 1816.
A similar cooling event today could stress already fragile food supply chains and spark economic instability. The shockwaves would be felt far beyond Naples.
Eyes on the Earth
As of now, there is no clear timetable for what may—or may not—happen next. Volcanoes are notoriously unpredictable. While warning signs can accumulate, the exact moment of eruption often remains elusive.
Nevertheless, scientists continue to monitor every rumble, bubble, and puff of gas with increasing urgency. Remote sensing tools, satellite data, ground deformation sensors, and gas spectrometers all play a part in the complex puzzle of forecasting volcanic behavior.
What makes Campi Flegrei particularly enigmatic is its dual nature: while it shows all the classic warning signs of volcanic unrest, it has also demonstrated periods of similar activity in the past without erupting.
Still, the current level of seismicity, coupled with the shallow depth of the magma and elevated gas output, suggests that this time could be different.
Read more: Researchers Are On High Alert After Sign That US Volcano Is About To Erupt
Nature’s Unpredictable Power
Campi Flegrei is not just another volcano; it is one of the few on Earth capable of altering the course of human history. While its slopes remain tranquil for now, the data coming in tells a story of pressure, movement, and potential rupture.
For those living near Naples, the Phlegraean Fields are a constant, if quiet, presence—a land that has seen civilizations rise and fall. For scientists, they are a living laboratory of planetary behavior. For the rest of the world, they are a reminder that even in the modern age, nature still holds the upper hand.
Preparedness, vigilance, and continued scientific observation are our best tools in the face of such unpredictable forces. One can only hope that this sleeping giant chooses to continue its nap.
