Image Source: GMS-5 visible, 4-5 October 1998

Comments: This brief eruption illustrates one of the problems of volcanic ash monitoring; that of level assignment of the plume. According to ground-based reports at the time, the maximum height of this eruption was about 5 to 6 km above sea-level, consistent with infared imagery and the majority of this visible sequence of images. However, shortly into this sequence, a large, high cloud appears and then starts to dissipate. Infrared imagery shows this cloud as being very cold, probably to an altitude of 15-16 km, and probably intruding into the stratosphere.

The TOMS image below (courtesy of the TOMS Volcanic Image Archive, maintained by the TOMS Volcanic Emissions Group) shows sulphur dioxide detected from the eruption, confirming a volcanic content to the cloud. However, no actual volcanic ash was detected by either GMS or TOMS.