New magnetic surveys of an active underwater volcanic system off the western coast of Italy, near the Phlegraean Fields and the Island of Ischia, have uncovered a series of previously unknown geological structures on the seabed. These include the remnants of an ancient caldera and a large submarine landslide. The findings come from a study conducted by a team of researchers from the National Institute of Geophysics and Volcanology (INGV) and the Institute of Marine Sciences of the National Research Council (Cnr-Ismar), published in the scientific journal Geomorphology.

While the Phlegraean Fields have been the focus of numerous studies, their underwater extension had not yet been analyzed and integrated with the nearby marine sectors. The new magnetic surveys identified significant anomalies, suggesting the presence of an ancient submerged volcano located slightly west of Ischia.

“One of the main outcomes of our study is undoubtedly the identification, based on seabed morphological analysis and magnetic anomalies, of a previously undescribed large caldera. This discovery could prove crucial for understanding the evolutionary history and volcanic activity of the Phlegraean Fields and Ischia,” explains Riccardo De Ritis, a researcher at INGV and the study’s lead author.

The research also highlighted magnetic features corresponding to both known regional faults and newly identified structures, which may reflect ongoing tectonic and volcanic processes in the area. “This study opens up significant avenues for mitigating volcanic risk in one of Italy’s most densely populated regions, while underscoring the critical role of marine geophysics in monitoring and investigating high-risk volcanic zones,” adds Salvatore Passaro, a researcher at Cnr-Ismar and co-author of the article.