Explains the problem, describes procedures used to cope with it, ways of monitoring and detecting hazardous conditions, and warning systems currently available to help mitigate the dangers.
Of 129 reported incidents, 94 are confirmed ash encounters, 79 of which entailed airframe or engine damage; 20 are low-severity events involving suspected ash or gas clouds; for 15 the data are insufficient to assess severity.
Summarizes the eruptions of this spectacular volcano and the consequences for the surrounding landscape, explains how volcanoes like this form, and how we monitor their activity to mitigate hazards they pose.