Diffuse CO2 emission rate from Pululahua and the lake-filled Cuicocha calderas,Ecuador

We report herein the first results of two soil CO₂ efflux surveys carried out at Cuicocha lake-filled and Pululahua caldera volcanic systems, Ecuador. A total of 172 and 217 soil CO₂ efflux measurements were taken at the surface environment of Pululahua and Cuicocha calderas respectively, by means of the “accumulation chamber” method during the summer of 2006 to constrain the total CO₂ output from the studied area. Soil CO₂ efflux values ranged from non-detectable up to 48.5 and 141.7 g m^{− 2} d^{− 1} for Cuicocha and Pululahua calderas respectively. In addition, probability graphs were used to distinguish the existence of different geochemical populations. Sequential Gaussian Simulation was used to construct an average map for 100 simulations and to compute the total CO₂ emission at each studied area: 106 and 270 t d^{− 1} (metric tons per day) for Cuicocha (13.3 km²) and Pululahua (27.6 km²) volcanoes respectively.