Prodigious sulfur dioxide emissions from Nyamuragira volcano, D.R. Congo

Nyamuragira (Virunga chain, D.R. Congo) is among Africa's most active volcanoes, but direct observations of its eruptions are rare. From 1978–2002 the Total Ozone Mapping Spectrometer (TOMS) instruments measured SO 2 emissions during each of Nyamuragira's 13 most recent eruptions. Due to continuous co‐eruptive SO 2 degassing, estimating the total atmospheric SO 2 loading resulting from eruptions of Nyamuragira is not straightforward. Using TOMS SO 2 plume cross‐sections and model wind profiles we derive eruptive SO 2 fluxes and SO 2 loss rates for emissions on 19 October 1998 and 6 February 2001, giving peak SO 2 fluxes of 0.21 and 0.74 Tg day −1 respectively and loss rates of ∼10 −6 –10 −5 s −1 . Based on current data, time‐averaged SO 2 emission rates at Nyamuragira are comparable to persistent emitters (Etna, Kilauea), but eruptive fluxes at Nyamuragira are much higher. Considering the alkaline composition of Virunga lavas, eruptive CO 2 fluxes could be seven times the SO 2 flux.