UV camera measurements of fumarole field degassing (La Fossa crater, Vulcano Island)

Abstract

The UV camera is becoming an important new tool in the armory of volcano geochemists to derive high time resolution SO 2 flux measurements. Furthermore, the high camera spatial resolution is particularly useful for exploring multiple-source SO 2 gas emissions, for instance the composite fumarolic systems topping most quiescent volcanoes. Here, we report on the first SO 2 flux measurements from individual fumaroles of the fumarolic field of La Fossa crater (Vulcano Island, Aeolian Island), which we performed using a UV camera in two field campaigns: in November 12, 2009 and February 4, 2010. We derived ~ 0.5 Hz SO 2 flux time-series finding fluxes from individual fumaroles, ranging from 2 to 8.7 t d −1, with a total emission from the entire system of ~ 20 t d −1 and ~ 13 t d −1, in November 2009 and February 2010 respectively. These data were augmented with molar H 2S/SO 2, CO 2/SO 2 and H 2O/SO 2 ratios, measured using a portable MultiGAS analyzer, for the individual fumaroles. Using the SO 2 flux data in tandem with the molar ratios, we calculated the flux of volcanic species from individual fumaroles, and the crater as a whole: CO 2 (684 t d −1 and 293 t d −1), H 2S (8 t d −1 and 7.5 t d −1) and H 2O (580 t d −1 and 225 t d −1).