New Insights Into the Recent Magma Dynamics Under Campi Flegrei Caldera (Italy) From Petrological and Geochemical Evidence

Abstract

The Campi Flegrei caldera is considered the most dangerous volcano in Europe and is currently in a new phase of unrest (started in 2000 and still ongoing) that has persisted intermittently for several decades (main crisis occurred from 1950 to 1952, 1970–1972, and 1982–1984). Here, by combining the petrological and geochemical data collected in recent decades with numerical simulations, we place new constraints on the source(s) of the current dynamics of the volcano. In particular, we show that the measured (N2‐He‐CO2) geochemical changes at the fumaroles of Solfatara hydrothermal site are the result of massive (about 3 km3) magma degassing in the deep portion (≥200 MPa, 8 km of depth) of the plumbing system. This degassing mechanism would be able to flood the overlying hydrothermal system with hot gas, thus heating and fracturing the upper crust inducing shallow seismicity and deformation. This implies that the deep magma transfer process (≥8 km) has been decoupled from the source of deformation and seismicity, localized in the first kilometers (0–4 km) of caldera‐filling rocks. This information on magma transfer depth can have important implications for defining the best monitoring strategies and for forecasting a future eruption. Finally, this study highlights how petrological and geochemical data allow us to explore the dynamics of the deep portion of the plumbing system and thus trace the occurrence of recharge episodes, in a portion of the ductile lower crust where magma transfer occurs in the absence of earthquakes.

Data analysis of the unsteadily accelerating GPS and seismic records at Campi Flegrei caldera from 2000 to 2020

“…The interpretation of the current prolonged unrest of CFc is a matter of open debate 28 , 32 , 108 . Various theories have been proposed and tested either on the bradyseism of 1983–1984 and on the mini-uplifts 62 , as well as on the decennial-like accelerating uplift after 2005.…”

Magma Transfer at Campi Flegrei Caldera (Italy) After the 1538 AD Eruption

“…This deep reservoir allows a better description of the post-eruptive subsidence along the caldera periphery, not explained using only the central shallower source. Also, this reservoir at 8 km depth is the top of the deeper portion of the plumbing system at Campi Flegrei, as constrained by petrological and geochemical data (Buono et al, 2022).…”

Exploring microstructure and petrophysical properties of microporous volcanic rocks through 3D multiscale and super-resolution imaging

“…Although attention must be paid to extend our results to all the types of microporous volcanic rocks, this study represents the first effort to systematically explore these “unconventional” digital rocks through digital rock physics, as well as offers a framework to deal with similar microporous structures and innovative imaging challenges (e.g., high-resolution imaging of large samples or materials to be preserved, 4D imaging with large experimental apparatus and/or high temporal resolution). Moreover, Campanian Ignimbrite tuff is thought to be one the most widespread subsurface rock at the Campi Flegrei caldera 37 , 38 , currently in a state of unrest since 2005 28 , 29 . Our findings will be employed in future studies to optimize the 3D investigation of core samples from geothermal drills in this area and time-resolved (4D) imaging during in-situ and/or ex-situ experiments to better constrain the ongoing dynamics at this large active caldera.…”