Soil CO2 flux measurements in volcanic and geothermal areas

The accumulation chamber methodology allows one to obtain reliable values of the soil CO₂ flux, ϕ_{soil CO2}, in the range 0.2 to over 10 000 g m⁻² d⁻¹, as proven by both laboratory tests and field surveys in geothermal and volcanic areas. A strong negative correlation is observed between Δϕ_{soil CO2}/Δt and ΔP_atm/Δt. Maps of classes of log ϕ_{soil CO2} for the northern sector of Vulcano Island, Solfatara of Pozzuoli, Nea Kameni Islet and Yanbajain geothermal field evidence that active faults and fractures act as uprising channels of deep, CO₂-rich geothermal or magmatic gases. The total diffuse CO₂ output was evaluated for each surveyed area.