Sulfur dioxide emissions from Papandayan and Bromo, two Indonesian volcanoes
Indonesia hosts 79 active volcanoes, representing 14% of all active volcanoes worldwide. However, little is known about their SO 2 contribution into the atmosphere, due to isolation and access difficulties. Existing SO 2 emission budgets for the Indonesian archipelago are based on extrapolations and inferences as there is a considerable lack of field assessments of degassing. Here, we present the first SO 2 flux measurements using differential optical absorption spectroscopy (DOAS) for Papandayan and Bromo, two of the most active volcanoes in Indonesia. Results indicate mean SO 2 emission rates of 1.4 t d −1 from the fumarolic activity of Papandayan and more than 22–32 t d −1 of SO 2 released by Bromo during a declining eruptive phase. These DOAS results are very encouraging and pave the way for a better evaluation of Indonesian volcanic emissions.