A transition from an elastic phase to an inelastic one, ie with possible fractures: these are the changes in the crust of the caldera of the Phlegraean Fields identified by the research published in the journal Nature and born from the collaboration between University College London and the National Institute of Geophysics and Volcanology. The data indicate that the observed change in the complex dynamics of the great caldera could lead to the halting of ground uplift phenomena and the resumption of slow subsidence.
"The study – explained Stefano Carlino of the Vesuvius Observatory of INGV – shows that, despite the ground level reached today is more than 10 centimeters higher than that reached during the bradyseismic crisis of 1984, the inelastic deformation is occurring with a lower level of stress than in 1984. This result suggests that during the caldera uplift episodes of the past decades, changes in the physical state of the crust have progressively occurred."
Changes that cannot be overlooked in the study of future evolution, in a current situation in which fluids (probably also magma and gas) are believed to be present moving at a depth of about 3 kilometers.
Since the 50s there have been many episodes of lifting of the territory of the Phlegraean Fields and this change of state, from elastic and inelastic regime, could mark an important passage: even a reversal of the current dynamics. "In the most critical scenario – observed Nicola Alessandro Pino of the Vesuvius Observatory of INGV – the persistence of the inelastic regime could lead to rapid fracturing of the most superficial crustal layers, with precursors that could be less intense than generally expected in the event of magma rising. However, the progressive and diffuse reactivation of fractures could cause depressurization of the hydrothermal system, with arrest of soil uplift and, therefore, the resumption of slow subsidence."