AI reveals hidden 'ring fault' that is unleashing earthquakes in Italy Technology So far in 2025, Campi Flegrei has produced five earthquakes above magnitude 4, and the volcano has been showing signs of unrest since 2005. Follow on Published On: Tue, 14 Oct 2025 06:01:32 PKT (Web Desk) - A new AI tool reveals that Campi Flegrei experienced more than 54,000 earthquakes between 2022 and 2025. By mapping these events, researchers discovered a huge, crisp, ring-shaped fault. An artificial intelligence (AI) model has revealed never-before-seen geological structures at Italy's Campi Flegrei volcano, including a clear "ring fault" that could unleash magnitude 5 earthquakes.

So far in 2025, Campi Flegrei has produced five earthquakes above magnitude 4, and the volcano has been showing signs of unrest since 2005. But most of the earthquakes triggered in the region are going undetected, according to a new study that used AI to pinpoint tens of thousands of seismic events that have gone under the radar over the past few years. "We've known that this is a risky place for a long time," study co-author William Ellsworth, a professor emeritus of geophysics at Stanford University, said in a statement. "Now we're seeing for the first time the geologic structures that are responsible." Over the past 40,000 years, Campi Flegrei has produced two of the largest eruptions in Europe, and evidence suggests the volcano's earlier history was just as explosive.

Scientists have been recording unrest at Campi Flegrei since the 1950s, but monitoring efforts increased in the 1980s after a swarm of 16,000 earthquakes prompted the evacuation of 40,000 residents. To investigate modern threats from Campi Flegrei, Ellsworth and his colleagues developed an AI tool capable of identifying earthquakes that previous methods couldn't pick out. Traditionally, seismologists identify earthquakes by analyzing seismograms, which are graphs with wiggly lines that represent shaking in the ground over time. Researchers look for a sudden increase in the wiggles' size, and this process is known as "phase picking," said study co-author Greg Beroza, a professor of geophysics at Stanford University.

"That's a simple and often effective means of picking a phase, but it doesn't 'learn' how to do it better so that it improves with time," Beroza told Live Science in an email. "In our approach, we train a machine learning model to pick phases. We base it on the collection of millions of examples where experts have done this already, and our method is designed to learn how to do this more effectively." The team chose to have their tool analyze Campi Flegrei before other volcanoes for several reasons, including there being an urgent need to better understand this volcano's behavior, Beroza said. More than 360,000 people live inside Campi Flegrei's 7-mile-long (11 kilometers) caldera, and roughly 1.5 million people reside in the wider area.

Unrest over the past 20 years ticked up in 2018 — and while there are currently no signs of an eruption, a particularly violent or shallow earthquake could present a huge danger to people as well as damage buildings, according to the statement. The results from the AI tool, published Sept. 4 in the journal Science, reveal that three-quarters of earthquakes at Campi Flegrei between 2022 and mid-2025 went undetected. While traditional methods documented 12,000 earthquakes in this period, AI shows the number was closer to 54,000.

By mapping the location of these earthquakes, the researchers discovered faults — cracks in Earth's crust that can grind against each other and cause earthquakes — that previous methods hadn't highlighted. Notably, the team found two faults converging beneath Pozzuoli, a town west of Naples where evacuations took place in the 1980s. The location of these faults suggests "an earthquake in the magnitude 5 range is not out of the question," Ellsworth said.