Fig. 4
A short-term variation of gas concentration molar ratios on 12 January 2015. a CO2/SO2 molar ratio, b H2O/SO2 molar ratio, c SO2/H2S molar ratio, and d H2/SO2 molar ratio. Grey circles show ratios obtained for high concentration peaks of SO2 ≥ 10 ppm, and white circles are ratios of low concentration peaks of SO2 < 10ppm