Bulletin of Volcanology

, Volume 68, Issue 1, pp 76–90

Comparative soil CO2 flux measurements and geostatistical estimation methods on Masaya volcano, Nicaragua


    • Earth Sciences DivisionLawrence Berkeley National Laboratory
  • Deborah Bergfeld
    • U.S. Geological Survey
  • Carlo Cardellini
    • Dipartimento di Scienze della TerraUniversità di Perugia
  • Giovanni Chiodini
    • Osservatorio VesuvianoIstituto Nazionale di Geofisica e Vulcanologia
  • Domenico Granieri
    • Osservatorio VesuvianoIstituto Nazionale di Geofisica e Vulcanologia
  • Nick Varley
    • Facultad de CienciasUniversidad de Colima
  • Cynthia Werner
    • Institute of Geological and Nuclear Sciences
Research Article

DOI: 10.1007/s00445-005-0423-9

Cite this article as:
Lewicki, J.L., Bergfeld, D., Cardellini, C. et al. Bull Volcanol (2005) 68: 76. doi:10.1007/s00445-005-0423-9


We present a comparative study of soil CO2 flux (\(F_{{\rm CO}_2 }\)) measured by five groups (Groups 1–5) at the IAVCEI-CCVG Eighth Workshop on Volcanic Gases on Masaya volcano, Nicaragua. Groups 1–5 measured \(F_{{\rm CO}_2 }\) using the accumulation chamber method at 5-m spacing within a 900 m2 grid during a morning (AM) period. These measurements were repeated by Groups 1–3 during an afternoon (PM) period. Measured \(F_{{\rm CO}_2 }\) ranged from 218 to 14,719 g m−2 day−1. The variability of the five measurements made at each grid point ranged from ±5 to 167%. However, the arithmetic means of fluxes measured over the entire grid and associated total CO2 emission rate estimates varied between groups by only ±22%. All three groups that made PM measurements reported an 8–19% increase in total emissions over the AM results. Based on a comparison of measurements made during AM and PM times, we argue that this change is due in large part to natural temporal variability of gas flow, rather than to measurement error. In order to estimate the mean and associated CO2 emission rate of one data set and to map the spatial \(F_{{\rm CO}_2 }\) distribution, we compared six geostatistical methods: arithmetic and minimum variance unbiased estimator means of uninterpolated data, and arithmetic means of data interpolated by the multiquadric radial basis function, ordinary kriging, multi-Gaussian kriging, and sequential Gaussian simulation methods. While the total CO2 emission rates estimated using the different techniques only varied by ±4.4%, the \(F_{{\rm CO}_2 }\) maps showed important differences. We suggest that the sequential Gaussian simulation method yields the most realistic representation of the spatial distribution of \(F_{{\rm CO}_2 }\), but a variety of geostatistical methods are appropriate to estimate the total CO2 emission rate from a study area, which is a primary goal in volcano monitoring research.


Carbon dioxideSoil gasAccumulation chamber methodGeostatisticsMasaya volcanoVolcano monitoringEmission rates

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© Springer-Verlag 2005