We present here new measurements of sulfur dioxide and hydrogen sulfide emissions fromVulcano, Etna, and Stromboli (Italy), made by direct sampling at vents and by filter pack and ultravioletspectroscopy in downwind plumes. Measurements at the F0 and FA fumaroles on Vulcano yielded SO2/H2Smolar ratios of 0.38 and 1.4, respectively, from which we estimate an H2S flux of 6 to 9 t · d 1 for thesummit crater. For Mt. Etna and Stromboli, we found SO2/H2S molar ratios of 20 and 15, respectively,which combined with SO2 flux measurements, suggest H2S emission rates of 50 to 113 t · d 1 and 4 to 8t · d 1, respectively. We observe that “source” and plume SO2/H2S ratios at Vulcano are similar, suggestingthat hydrogen sulfide is essentially inert on timescales of seconds to minutes. This finding has importantimplications for estimates of volcanic total sulfur budget at volcanoes since most existing measurements donot account for H2S emission.
|Numero di pagine||11|
|Rivista||GEOCHIMICA ET COSMOCHIMICA ACTA|
|Stato di pubblicazione||Published - 2005|
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