The Phlegraean Fields, now considered one massive supervolcano, are beginning to stir, making the scientific community uneasy.
These volcanic fields, nestled just west of Naples, Italy, are among the top eight emitters of volcanic carbon dioxide worldwide.
Since 2005, one spot in particular—the Solfatara crater—has been releasing increased volumes of gas, catching the attention of researchers and locals alike.
Gas emissions at Solfatara crater
Gianmarco Buono, a volcanologist at the Italian National Institute of Geophysics and Volcanology (INGV), is leading a study to understand what’s behind this surge in gas emissions.
“Estimating the source of the carbon dioxide is important to properly reconstruct what is happening in the magmatic system and the hydrothermal system,” says Buono.
His team aims to provide a tool that can distinguish between carbon dioxide coming from magma and that released by other processes—a method that could be useful in volcanic regions around the world.
What exactly is a supervolcano?
In the simplest of terms, a supervolcano is essentially a volcano on steroids. It’s a massive volcanic system capable of producing eruptions thousands of times more powerful than a regular volcano.
These eruptions can eject more than 1,000 cubic kilometers of material into the atmosphere, which can have catastrophic effects on the global climate and environment.
You’ve probably heard of places like Yellowstone National Park in the United States—that’s one of the most famous supervolcanoes.
When a supervolcano erupts, it can form a giant caldera, which is a huge crater that can span dozens of miles.
The sheer scale of these eruptions makes them rare, but they’re definitely something scientists keep an eye on due to their potential impact on life across the planet.
Numbers speak volumes
Today, the Solfatara crater emits between 4,000 and 5,000 tons of carbon dioxide each day. To put that into perspective, that’s equivalent to the emissions from burning about 500,000 gallons of gasoline daily.
In their recent paper published in Geology, Buono and his colleagues estimate that 20% to 40% of this carbon dioxide comes from the dissolution of calcite in the surrounding rocks. The remaining 60% to 80% is traced back to underground magma.
Science behind the Solfatara crater gas
When magma moves closer to the Earth’s surface, the pressure decreases, causing gases that were trapped inside to escape. These gases include water vapor, carbon dioxide, and sulfur dioxide.
Scientists keep a close eye on volcanoes by monitoring earthquakes, measuring ground deformation, and analyzing gases emitted from fumaroles—openings in the Earth’s crust that release steam and gases.
An uptick in gas emissions can be a sign of potential volcanic activity. However, not every increase leads to an eruption.
Sometimes, carbon dioxide is released when hot underground fluids interact with the rocks above, rather than from magma itself.
Monitoring changes over decades
Since 1983, the Italian National Institute of Geophysics and Volcanology has been keeping tabs on the gas emissions from the Solfatara crater.
By studying the ratios of nitrogen, helium, and carbon dioxide, researchers initially concluded that the gases were primarily from deep magma sources.
“We focused mainly on geochemical variation, especially for carbon dioxide, helium, and nitrogen, because they are non-reactive species. They contain information about what is happening in the magma,” Buono explains.
But things started to change in 2005. The data began to deviate from the typical chemical signatures of magma-derived gases. This shift continued over time, accompanied by rising temperatures in the shallow hydrothermal system.
By 2012, the alert level for the region was raised from green to yellow, signaling heightened activity but not an immediate threat of eruption.
Clues from the Earth’s movements
The area didn’t just experience changes underground. Small earthquakes and noticeable ground deformation were also observed.
These signs pointed toward the circulation of hot fluids beneath the surface. When these hot, acidic fluids interact with calcite in the rocks, they can release additional carbon dioxide.
Previous studies involving drill cores of the local rocks revealed that the calcite present has a composition similar to the gases being emitted.
Based on this information, Buono’s team estimated that 20% to 40% of the carbon dioxide at the Solfatara crater comes from the breakdown of calcite in the host rocks.
The Phlegraean Fields have a long volcanic history, with activity dating back approximately 40,000 years. The most recent eruption occurred in 1538.
Since the 1950s, the region has experienced several phases of unrest, reminding us that Earth’s geology is always in motion.
Why does this matter?
Understanding the source of carbon dioxide emissions in volcanic regions is crucial for public safety and environmental monitoring.
By distinguishing between gases released from magma and those from other processes, scientists can better predict volcanic activity and assess potential risks.
Buono’s research not only sheds light on the complex interactions beneath the Phlegraean Fields but also provides tools that could be applied to other volcanic areas.
As he notes, “Our aim is to provide a tool to better discriminate the contribution of magmatic and non-magmatic carbon dioxide that can also be applied to other systems.”
Solfatara crater and the future
To sum it all up, figuring out what’s really going on beneath the Phlegraean Fields and Solfatara crater is a big deal—not just for the science buffs but for everyone living on Earth.
Buono’s team has shown that the spike in carbon dioxide emissions isn’t just magma pushing its way up. A good chunk of that gas is actually coming from hot fluids interacting with calcite-rich rocks underground.
This kind of information is gold because it helps us keep a closer eye on volcanic activity and, more importantly, keeps people safe.
Looking ahead, keeping tabs on these emissions, and understanding their sources is key. By knowing whether the carbon dioxide is from magma or from rock interactions, scientists can better predict what’s coming next.
The Phlegraean Fields are a vivid reminder that our planet is always on the move. Scientists like Buono will keep unraveling the mysteries beneath our feet, helping us understand the dynamic planet we call home.
The full study was published in the journal Geology.
