The eruptive fissure, seen from NW 28 September at 13:20. Most of the degassing takes place on two vents along the fissure, the northernmost part of the rampart and from the central part of the rampart. These two sources merge into one plume. Downwind, dense volcanic gases separate and descend. Further downwind a second plume, rich in water vapour, reaches higher elevation than the first plume.