Fig. 6
From: Understanding and forecasting phreatic eruptions driven by magmatic degassing
Monitoring of gas compositions can provide crucial insight into the influence of the magmatic system. Generally, as a volcanic system reactivates, the gas emissions will evolve from CO2-rich to SO2-rich. This plot shows proposed generalized fields for the characterization of hydrothermal-magmatic gas emissions, based on recent studies of Central American volcanoes (Aiuppa et al. 2014; de Moor et al. 2016a, b, 2017a). The exact boundary lines would vary with tectonic setting and other factors (Aiuppa et al. 2017), but are shown here with key gas ratio values considered appropriate for Central American volcanoes