The volcanic activity changes occurred in the 2021–2022 at Vulcano island (Italy), inferred by the abrupt variations of soil CO2 output

Abstract

The active cone of La Fossa is a close conduit volcano characterized by solphataric activity, manifested by discharging fluids through fumaroles and soil degassing. Since 1978 several degassing crises have been observed and interpreted as early signals of volcanic unrests. Recently, from June 2021 to May 2022, we measured the changes in soils CO2 release to evaluating the level and duration of the actual exhaling crises. The CO2 output has been evaluated by surveys carried out in anomalously degassing areas, located both in the La Fossa cone summit area and in other peripheral zones, coupled to near-real time monitoring data acquired by three automated stations. The strong and deep input of volatiles released from an underlying magma batch modified the chemical composition of the shallow plumbing system, bringing the system to a higher level of CO2 total pressure. This work highlights that a geochemical networks of stations, located at some distance from the fumaroles release and/or from eruptive conduits, is useful and can be applied to characterizing and monitoring any other active volcanic system. This type of studies can be useful to contribute to forecast the next evolution of the studied systems.