[Reading Science] Naples, Italy Issues 'Alert' for Ultra-Powerful Volcanic Eruption

London College London Research Team
"Signs of Campi Flegrei Volcano Eruption"
VEI 7 Grade 'Superpower Volcano'
Risk of 'Mass Extinction' in Case of Maximum Eruption
"Crust Weakening Increases Possibility of Small Earthquakes and Eruptions"

A 'Baekdusan-level' supervolcano located in Naples, Italy, is showing signs of erupting again after 500 years, raising alarms.

Campi Flegrei volcano near Naples, Italy. The photo was taken in June 2013, showing mud erupting around the fumaroles. Photo by Yonhap News

A research team from University College London in the UK published a paper on this topic on the 9th in the international journal Communications Earth & Environment. The volcano identified as being at risk of eruption is the Campi Flegrei volcano near Naples, a city in southern Italy famous for its "beautiful harbor." Naples has recently become familiar to us due to the outstanding performance of national soccer player Kim Min-jae. The last eruption occurred about 500 years ago in 1538, and activity has recently increased again. Italian authorities raised the alert level for this volcano from the normal "Green" to the cautionary "Yellow" in 2012. In December 2016, Italian scientists also published research indicating signs of awakening from dormancy and potential re-eruption.

The Campi Flegrei volcano was formed about 39,000 years ago by a massive lava eruption, and a huge disaster is expected if it erupts. It is located near Naples, which has a population of 1.5 million. Within 11 km of the crater, there are 500,000 residents. The research team particularly warned that if this volcano erupts at its predicted maximum intensity, it could cause a worst-case scenario of "mass extinctions." Volcanic ash and gases are expected to spread into the stratosphere at altitudes above 10 km, and a tsunami with a height of 33.5 meters is anticipated. The paper states that sulfur and toxic volcanic ash could plunge the Earth into a winter lasting several years, killing crops and causing mass extinction events. Campi Flegrei means "burning fields" in Italian and is located opposite the famous volcano Vesuvius, which lies to the west of Naples. It consists of 24 large and small craters extending from the massive caldera lake to the nearby Bay of Pozzuoli.

Campi Flegrei is generally considered a supervolcano (Volcanic Explosivity Index, VEI 7?8). The scale and intensity of a volcano are classified by the Volcanic Explosivity Index (VEI), which is based on crater size, expected explosive power, and eruption cloud height. It is divided into nine levels from 0 to 8. The most powerful volcano in the last 10,000 years, Baekdusan, was VEI 7. The underwater volcano in Tonga, which erupted last year in the South Pacific, is classified as VEI 6. Typically, supervolcanoes are VEI 7?8, meaning they can eject about 100 to 1,000 cubic kilometers or more of material. Campi Flegrei’s largest eruption in history produced about 285 cubic kilometers of ejecta, corresponding to VEI 7, similar to Baekdusan. Although it is slightly less than VEI 8, it remains extremely dangerous. In particular, the fluorine contained in volcanic ash and gas clouds can be released in amounts sufficient to kill plants and cause fluorosis in animals.

2018 Hawaii volcanic eruption. Archive photo. Not related to the article. [Image source=Yonhap News]

The Campi Flegrei volcano showed active phases three times in the mid-20th century?in the 1950s, 1970s, and 1980s. Experts say volcanic activity resumed about 10 years ago, causing ground instability in the nearby town of Pozzuoli. The ground has risen about 4 meters since the 1950s, increasing by about 10 cm annually over the past decade. Activity has become even more intense recently. In April alone, a record-breaking 600 small earthquakes occurred, unsettling local residents.

The research team attributes these frequent earthquakes to volcanic gas activity occurring about 2 km beneath the surface, causing the crust to stretch, twist, and slip like a sponge. To analyze the eruption potential, the team combined seismic and ground uplift measurements to assess the tensile strength (maximum stress) and rupture probability of the crust in the area. The results showed that strong gas and magma activity deep within the crust has gradually weakened and bent the surface since the 1950s, reducing the crust’s tensile strength to one-third of what it was in 1984.

However, the research team believes the likelihood of a large-scale eruption in the immediate future is low. Instead, they concluded that weaker earthquakes and eruptions will become more frequent as the crust weakens. For a powerful volcanic explosion to occur, volcanic gases must be trapped and accumulate pressure inside solid rock beneath the surface, and lava must be able to move rapidly through fractured crust. Currently, the ground around Campi Flegrei is weakened by continuous activity, so even small pressure or minor lava accumulation could cause rupture, making smaller eruptions more likely.

Stefano Calino, a researcher at the Vesuvius Observatory, said, "Like other volcanoes that have been quiet for generations, Campi Flegrei may exhibit small-scale activity before becoming quiet again rather than a sudden, powerful eruption." However, he added, "We cannot say what will happen yet, and we must prepare for all possibilities."