An active volcano just north of Guam, in the Northern Mariana Islands. For several weeks in mid 2005 the eruptions caused flight planning problems for Qantas flights to and from Japan. On this day the ash cloud was stretching approx 700 miles to the west, although to a maximum height of around 7000-10,000 feet. However, note the isolated cumulus activity - which has the potential to carry ash and dust to aircraft cruise levels.