Hydrothermal pressure-temperature control on CO2 emissions and seismicity at Campi Flegrei (Italy)

Fluids supplied by stored magma at depth are causal factors of volcanic unrest, as they can cause pressurization/heating hydrothermal systems. However, evidence for links between pressurization, CO2 emission and volcano seismicity have remained elusive. Here, we use recent (2010−2020) observations Campi Flegrei caldera (CFc) to show pressure, gas CFc share common source areas well-matching temporal evolutions. We interpret the escalation in surface emissions caused pressure-temperature increase top a vertically elongated (0.3–2 km deep) front. Using mass (steam) balance considerations, pressurization is causing energy transfer from fluids host rocks, ultimately triggering low magnitude earthquakes within seismogenetic volume containing system. This mechanism probably other worldwide calderas similar activity state.