Report on Pavlof (United States) — August 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 8 (August 1987)
Managing Editor: Lindsay McClelland.
Pavlof (United States) Continued ash emission
Please cite this report as:
Global Volcanism Program, 1987. Report on Pavlof (United States). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:8. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198708-312030.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
Eruptive activity was continuing in late August. At about 1130 on 29 August, pilot Chuck Nickerson (Reeve Aleutian Airways) observed a thick dark ash horizon at 1200-1800 m altitude extending 50 km SSW from Pavlof. The ash appeared to originate from a SE flank vent. Below that vent, white steam was rising along a 100 m, narrow, flow-like, feature or crack. At 1550 pilots Andy Livingston and James Fredenhagen (Reeve Aleutian Airways) observed from Sand Point (88 km E), a diffuse ash layer at 1200-1800 m altitude that extended at least 15 km SW. Ben and Lorie Kirker reported that no ash reached King Cove, about 40 km SW. On 30 August at 1400 Theresa Dubber (FAA) saw no ash being emitted during a clear view of the volcano from Cold Bay.
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: J. Reeder, ADGGS.