Gas Monitoring of Volcanic-Hydrothermal Plumes in a Tropical Environment: The Case of La Soufrière de Guadeloupe Unrest Volcano (Lesser Antilles)

Fumarolic gas survey of dormant volcanoes in hydrothermal activity is crucial to detect compositional and mass flux changes emissions that are potential precursors violent phreatic or even magmatic eruptions. Here we report on new data for the chemical compositions (CO 2 , H S, SO ) fluxes fumarolic (97–104°C) from La Soufrière volcano Guadeloupe (Lesser Antilles) obtained both mobile MultiGas measurements permanent survey. This paper covers period 2016–2020, encompassing a enhanced unrest including an abrupt seismic energy release (M 4.1) April 27, 2018. Our dataset reveals CO /H S trends correlated evolution surface other geochemical geophysical parameters. We demonstrate that, under tropical conditions (high humidity rainfall), surveys low-T permit distinguish deeply sourced signals volcanic secondary degassing due shallow forcing processes such as water-gas-rock interactions system meteorological effects.