Report on Pavlof (United States) — August 1986
Scientific Event Alert Network Bulletin, vol. 11, no. 8 (August 1986)
Managing Editor: Lindsay McClelland.
Pavlof (United States) Strombolian activity and ash emission ends
Please cite this report as:
Global Volcanism Program, 1986. Report on Pavlof (United States). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 11:8. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198608-312030.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
Airplane pilots frequently reported vapor and ash rising to 3.5-4 km altitude from Pavlof through 22 August (table 1). Sailors observed lava fountaining during the evening of 13 August, but airplane pilots generally do not fly close enough to the volcano to observe Strombolian explosions and most flights are in daylight when eruptive glow is unlikely to be evident. No pilot reports of activity were received between 22 August and 8 September, although there was some clear weather during that period. On 8 September, vigorous vapor emission was observed from Sand Point, 90 km E. During an overflight on 12 September, only minor steaming was observed.
Geologic Background. The most active volcano of the Aleutian arc, Pavlof is a 2519-m-high Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and its twin volcano to the NE, 2142-m-high Pavlof Sister, form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that tower above Pavlof and Volcano bays. A third cone, Little Pavlof, is a smaller volcano on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, Pavlof has been frequently active in historical time, typically producing Strombolian to Vulcanian explosive eruptions from the summit vents and occasional lava flows. The active vents lie near the summit on the north and east sides. The largest historical eruption took place in 1911, at the end of a 5-year-long eruptive episode, when a fissure opened on the N flank, ejecting large blocks and issuing lava flows.
Information Contacts: T. Miller, USGS Anchorage; J. Taber, LDGO; J. Reeder, ADGGS.