Increasing CO₂ flux at Pisciarelli, Campi Flegrei, Italy

Abstract. The Campi Flegrei caldera is located in the metropolitan area of Naples (Italy) and has been undergoing different stages of unrest since 1950, evidenced by episodes of significant ground uplift followed by minor subsidence, increasing and fluctuating emission strengths of water vapor and CO₂ from fumaroles, and periodic seismic crises. We deployed a scanning laser remote-sensing spectrometer (LARSS) that measured path-integrated CO₂ concentrations in the Pisciarelli area in May 2017. The resulting mean CO₂ flux is 578 ± 246 t d⁻¹. Our data suggest a significant increase in CO₂ flux at this site since 2015. Together with recent geophysical observations, this suggests a greater contribution of the magmatic source to the degassing and/or an increase in permeability at shallow levels. Thanks to the integrated path soundings, LARSS may help to give representative measurements from large regions containing different CO₂ sources, including fumaroles, low-temperature vents, and degassing soils, helping to constrain the contribution of deep gases and their migration mechanisms towards the surface.