The role of the aquifer in soil CO2 degassing in volcanic peripheral areas: A case study of Stromboli Island (Italy)

The results of this study show that in the volcanic peripheral area, the degassing process of soil CO2 is determined not only by the CO2 released directly from the magma but also by gas-water interactions in the aquifer. The aquifer is able to dissolve the high amount of CO2 discharged by the magmatic system. Moreover, the “residuals” of CO2 flux diffused from the soil show a delay on the order of ~ 1 month with respect to the pCO2 in equilibrium with the aquifer. The soil CO2 flux is therefore not directly linked to the uprising of magmatic CO2 but instead depends on the CO2 discharged from the aquifer, which buffers and modulates the volatile changes released by the magmatic system.