On 4th November 2008 the atmospheric sensor GOME-2 (Global Ozone Monitoring Experiment) detected a big SO2-plume over Yemen with sulphur dioxide amounts of more than 40 DU. So far no observation from ground nor any eye-witness have reported on the eruption. With the aid of backward trajectory analysis a trajectory density map was generated and so it was possible to derive further information about the eruption source and characteristics. Following the analysis the source is located close to Erta Ale volcano in the dessert of Danakil in Ethiopia. At the north flank of Erta Ale are two small volcanoes called Alu and Dalaffilla which are the most probable eruption source.
The trajectory matching technique also enables to estimate the height of the SO2 plume and the eruption time. The sulphur dioxide plume reached heights up to 14 km. The eruption time window lies between 8 and 12 UTC on 3rd November.