Soil gas emanations as precursory indicators of volcanic eruptions

Field measurements conducted on several active volcanoes in Italy, the Lesser Antilles, and Indonesia demonstrate the common Occurrence of diffuse soil gas emanations from the volcanic piles, at distances from active craters or fumarolic zones. These emanations consist essentially of carbon dioxide and rare gases and their genetic link with crater fumaroles and/or magma degassing at depth can be verified both chemically and isotopically. We emphasize here the potential use of these fluids for continuous volcano monitoring and eruption forecasting.