Différenciation de l’émanation magmatique: réactions H2S + SO2 dans les gaz volcaniques. Vulcano (Italie), 1923–1979

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Contribution des Sondes Aérologiques Motorisées à l’Etude de la Physico-Chimie des Panaches Volcaniques

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A Mesoscale Study of the Element Composition of Aerosols Emitted from Mt. Etna Volcano

International audienceAn aircraft survey was carried out for the study of the gaseous and particulate emissions over Mt Etna Volcano in September 1983. Samples were collected in the range from 10 to 300 km; a satisfying conservation of the elemental composition of the aerosol has been observed. Some activity fluctuation, 150 km from the emitter, was attributed to an ash fall episode. Sampling assumed that some crustal elements in the volcanic aerosol can be used to measure the plume dilution factor. New estimations of volcanic particulate fluxes are given

Geochemistry of Sulfur in Mount Etna Plume

International audienceAircraft measurements of sulfur compounds and trace elements including Po 21ø were carried out in the plume of the Mount Etna volcano, at distances 10 to 260 km from the crater. The experiment was performed in September 1983 following the large lava emission of March-August 1983. Trace elements, particularly Po 21ø and Si, were measured with the aim of calculating their atmospheric dilution and evaluating their outputs. This study enabled us to determine the SO 2 to SO,• conversion rates to be between 2.2 x 10-6 and 4.0 x 10-s s-• in a cloud free anticyclonic situation. The main process of SO 2 removal in a volcanic plume should be a heterogeneous process of adsorption of this gas onto large particles. Emission fluxes of SO 2 were found to vary between 27 and 38 kg s-•, leading to a mean Po 2•ø output of 0.4 Ci/d