A new artificial intelligence model developed at Stanford University has enabled scientists to detect thousands of previously undetected earthquakes in Italy’s Campi Flegrei volcanic region. The technology allows researchers to identify seismic events that earlier tools could not discern from large sets of monitoring data.
The research is a collaboration between Stanford University, Italy’s National Institute of Geophysics and Volcanology (INGV) – Osservatorio Vesuviano, and the University of Naples Federico II. According to the study, published in Science on September 4, the AI model identified four times as many earthquakes as previous methods and revealed previously unknown faults in the area.
“Seismicity could change at any time, and that may be the most important thing about this study: this capability of getting a clear view is now operational,” said Greg Beroza, a geophysics professor at the Stanford Doerr School of Sustainability and co-author of the study. “INGV is now running the tool by themselves as needed, so it should be helpful for scientific response and ultimately public response if something changes.”
Campi Flegrei is an active volcano located near Naples in a densely populated area with more than 500,000 residents. The region has experienced periods of unrest since the late 1950s. Seismic activity increased significantly in 2018, with five earthquakes above magnitude 4 recorded in early 2025. The new approach expanded detected seismic events from about 12,000 to over 54,000 between 2022 and 2025.
The data uncovered two faults converging under Pozzuoli—a town west of Naples—which has been closely monitored since unrest in the early 1980s led to land uplift exceeding six feet and prompted evacuation orders for approximately 40,000 people.
“These long faults suggest that an earthquake in the magnitude 5 range is not out of the question,” said Bill Ellsworth, co-director of the Stanford Center for Induced and Triggered Seismicity and study co-author. “We’ve known that this is a risky place for a long time, since the ’80s when part of the city was evacuated, and now we’re seeing for the first time the geologic structures that are responsible.”
Campi Flegrei’s caldera—an eight-mile-wide depression formed by major eruptions nearly 39,000 and 15,000 years ago—has produced some of Europe’s largest eruptions within the past 40 millennia. However, Beroza noted: “One of the biggest concerns in the short term in Campi Flegrei is not an eruption, but a moderate earthquake at shallow depth.”
Beroza also commented on new insights into seismic structure: “Previously, the structure of seismicity in the caldera was indistinct, and now we’ve seen a very thin and well-marked ring fault that is consistent with surface features especially offshore—and also with areas being uplifted.”
Lead author Xing Tan described how Italian collaborators were surprised by these findings: “Our Italian colleagues were surprised to see the ring so clearly,” Tan said. “They expected to see something in the south where previous data had revealed scattered seismicity but in north they’d never seen it so clearly.”
The researchers concluded that inflation within Campi Flegrei’s caldera appears to be driving earthquake activity through pressure rather than magma movement upward toward Earth’s surface. They found no evidence suggesting imminent magmatic eruption risk.
The project received support from several sources including Dipartimental Project LOVE-CF; Pianeta Dinamico project Nemesis; a Stanford University Doerr School Discovery Grant; RETURN Extended Partnership; and European Union Next-GenerationEU funding.
