Breakthrough at Campi Flegrei: Signal discovered that precedes the strongest earthquakes

Naples - A potentially decisive step forward in understanding seismic phenomena at Campi Flegrei. A new study, published in the prestigious journal JGR Solid Earth, has identified for the first time a clear "preparatory phase" preceding the highest magnitude earthquakes.

The research, the result of a collaboration between the Federico II University of Naples, the National Institute of Oceanography and Experimental Geophysics (OGS), and the University of Genoa, opens up new possibilities for the future development of predictive models.

So, what happens before a significant earthquake? According to the team of scientists, there's a combined increase in ground uplift, known as bradyseism, and the energy released by swarms of microearthquakes.

"We analyzed twenty seismic sequences recorded between 2015 and 2024," explains Antonio Giovanni Iaccarino of the University of Naples, lead author of the study. "We wanted to understand whether these phenomena were connected and whether it was possible to recognize precursor signals."

The answer was yes, leading to the identification of a key parameter, the 'residual strain', which describes the balance between accumulated deformation and released seismic energy.

Based on this data, integrated with measurements from the Vesuvius Observatory (INGV), the research team was able to develop a first, promising predictive model. "The model can estimate the potential magnitude of major events several days in advance," continues Iaccarino.

However, the researcher tempers enthusiasm: "It's still too early to talk about real forecasts. Uncertainties are still large, and the risk of false or missed alerts makes these tools unusable for civil defense purposes."

The link between ground deformation and seismicity is the main driver of the Phlegraean Fields phenomenon. "Understanding this connection is crucial to interpreting the system's evolution and improving risk assessment," comments Matteo Picozzi, Director of the OGS Seismological Research Center. Understanding how these preparatory phases evolve, he adds, "can help us make more timely and informed decisions in the event of a crisis."

The research doesn't stop there. The goal is now to expand the study, in collaboration with the INGV, and test the approach on other active volcanic systems around the world. "I believe that thanks to the joint effort of volcanologists and seismologists, we can refine our predictive capabilities," concludes Iaccarino. This is the first step on a journey that could, in the future, revolutionize seismic and volcanic risk management, not only in Naples but globally.