Have you ever seen the boiling water in a pressure cooker push against the lid, making it vibrate? Well, imagine the same thing, but under your feet, on a gigantic scale. According to Tiziana Vanorio, geophysicist from Pozzuoli and professor at Stanford University, this is exactly what is happening in the context of the bradyseism that is affecting the Campi Flegrei, in Campania. Not magma ascents, as has always been believed, but a colossal geothermal system fed by rainwater from the Campanian Plain.
And the good news is that this bradyseism could be mitigated with targeted interventions, such as the draining of some large wells built by Agip forty years ago, to reduce the pressure that is literally lifting the ground.
Bradyseism, a pressure cooker under our feet
I know that talking about bradyseism in this period generates concern: the person speaking to you lives in the Campi Flegrei and can testify to it, but understanding what is really happening can help us feel more at ease. According to the studies of Dr. vain, as mentioned, what is raising the ground in the Campi Flegrei is not the rising magma (which would cause earthquakes much stronger than the current ones), but a mechanism that is simpler to understand.
Imagine a system made of three elements: a “burner” (the deep magma chamber), a “pot” full of water (the geothermal reservoir), and a “lid” (the overlying rock that covers everything). Rainwater (technically called “meteoric water”) infiltrates the ground from the Campanian Plain, traveling underground from Nola to Caserta through porous rocks. When this water reaches the geothermal reservoir about 3 km deep, it is heated to over 350 degrees by the magma chamber below.
At these temperatures and pressures, water behaves like steam in a pressure cooker: it pushes upwards and, when the pressure becomes too high, it causes small fractures in the rocks that we perceive on the surface as earthquakes.
A practical and innovative solution
The most interesting part of Tiziana Vanorio’s theory is that, if confirmed, it also offers a practical solution: removing the “fuel” from the system. How? In two ways:
- Improve stormwater drainage through the Camaldoli and Regi Lagni riverbeds, to reduce the amount of water that infiltrates into the subsoil.
- Drain the thirteen wells built by Agip in the 80s in the San Vito area, to reduce the pressure already present in the geothermal system.
Bradyseism is like a pressure cooker in which rainwater, heated to over 350 degrees, generates an upward thrust that lifts the ground and causes earthquakes.
Another interesting point raised by the scientist concerns drilling carried out in 2020 in the Pisciarelli area. If this well was not properly sealed, this hypothesis needs to be verified further, could continue to feed the tank with new water, worsening the phenomenon instead of alleviating it.
A paradigm shift
These studies, the result of collaboration between the Stanford University andUniversity of Naples, are a radical change compared to the interpretations proposed so far by theINGV and by 'Vesuvius Observatory. Using techniques such as the seismic tomography (a kind of CT scan of the subsoil) and core sampling analysis (rock samples extracted from various depths), the team precisely identified the structure of the caldera.
If this theory is correct, bradyseism becomes a more manageable phenomenon than previously thought. We could continue to live in the Campi Flegrei, “but with awareness and precaution,” to use the words of Bishop Carlo Villano, present at the conference “Mechanisms, Causes and Mitigation Strategies” in which this theory was presented.
Knowing the “enemy” (and then, when man and nature are involved, Leopardi forgive me, you always have to understand who is the enemy of whom) is the first step to defeat it, or at least to live with it safely. And Vanorio's theory offers us a new perspective that, if confirmed, could represent an important step towards the mitigation of bradyseism in the Campi Flegrei.
