A new study by the National Institute of Geophysics and Volcanology (Ingv), published in the scientific journal AGU Advancesreveals the presence of one weaker layer of what was thought in the crust under the Caldera dei Campi Flegrei, located between 3 and 4 km deepwhich could help explain the phenomenon of bradyseism he is earthquakes in the area. Being very porousin fact, would favor theaccumulation of fluids of magmatic originwhich when they increase in volume can cause soil deformations. This feature has been identified by examining the speed of propagation of seismic waves in the subsoil of the caldera and analyzing rock samples extracted from a geothermal well about 3 km deep. The study was published a few days after that of the University of Stanford, which attributes the responsibility of seismic phenomena to waters of meteoric origin which accumulate in the geothermal tank at 2 km deep. The discovery of the Ingv, which constantly monitors the situation of the Flegrei fields with the weekly bulletins, contributes to the increasingly in -depth understanding of the volcano behavior and consequently to one more effective risk prevention.
The study of the fragile layer of crust under the Caldera dei Campi Flegrei
The study was conducted within the Love CF projectfinanced by the Ingv, and is the result of a collaboration between theIngvtheUniversity of Grenoble Alpes and theUniversity of Bologna. The researchers analyzed rocky samples extracted from a geothermal well about 3 km deep located near the center of the Caldera and the data of the seismic tomography of the subsoil of the Caldera, which is based on the speed of the seismic waves, variable according to the materials they meet. The tomography, in particular, provided high -resolution three -dimensional images of the subsoil up to 4 km deep. An area was thus identified that is particularly porous, and therefore less resistantlocated between 2.7 and 4 km deep Among the deep carbonate rocks and superficial volcanic tuffs. In the voids of this layer they can accumulate fluids of magmatic origin. “These fluids, trapped”explains Lucia Pappalardo, Ingv researcher and co -author of the study, “They progressively increase in volume and pressure, triggering soil deformations and seismic activity”.
Inside the weak layer during the eruptive phases of the past are Infiltrated small accumulations of magma (called dicchi) which then cooled without reaching the surface and contributed to making the area less resistant. In the past, for example during the eruption of 1538, after a phase of stasis these accumulations have started up again before having cooled down, then on the surface. The researchers also found that i earthquakes of magnitude greater than 3 occurred between 2000 and 2025 are concentrated above the weak layer. In conclusion, the weak layer can carry out a crucial role in the accumulation of overpressurecausing deformations and seismicity and influencing in the future a possible ascent of magma.
The importance of discovery on the functioning of the volcano
The discovery shows the importance of examining the deep structure of the Caldera dei Campi Flegrei to better understand the mechanisms at the origin of seismicity. To do this, we need continuous monitoring that involves different disciplines as underlined by Mauro Antonio di Vito, Director of the Vesuvian Observatory (Ingv-Ov):
This research does not directly affect our short -term forecasts, but it is a fundamental piece to understand the behavior of the volcano and improve our ability to monitor it. Only with an increasingly detailed knowledge of the volcanic system and its dynamic can we hope to anticipate critical signals and reduce the risks for people.
