Prélèvement et analyses des condensats de fumerolles sur volcans actifs: Soufrière de la Guadeloupe (1976–1977) et Pouzzoles et Vulcano (Italie) (1978)

The cooling of volcanic gases generates sublimates, condensates and gases. Condensates were sampled and analysed on different volcanoes: On Guadeloupe, phreatic eruptions occur when pH of condensates has maintained higher than 4 to 5 for 3 to 7 days. After the phreatic eruption, pH decreases to 1.5 to 2. At Pozzuoli and Vulcano it is possible to distinguish between gases washed by superficial waters (low mineral contents and high pH) and gases less affected by condensation and dissolution in the ground (high mineral contents and low pH).