Carbon Dioxide Emissions from the Rotorua Hydrothermal System, New Zealand

Abstract

Carbon dioxide fluxes were measured at 952 locations across the greater Rotorua hydrothermal system in the Taupo Volcanic Zone of New Zealand during 2003. Measurements were concentrated in regions that previously exhibited elevated levels of carbon dioxide in soil gas measurements (20-50 m spacing), and also dispersed across the greater Rotorua city area (100-200 m spacing). Flux measurements and modeling concur with previous analysis of the hydrothermal system with upwelling regions showing the highest CO2 emissions. The highest fluxes were measured in the Ngapuna region suggesting that flow into this area is the most primitive (i.e., least degassed). Similar high fluxes were measured in the Whakawareware, Arikikapakapa Golfcourse, and Kuirau park region suggesting partially degassed fluids supplying these regions. The greatest extents of degassing areas were observed in known thermal regions; however, elevated levels of soil CO2 flux were also observed in isolated patches throughout residential and commercial areas presenting a probable health risk.