Report on Pavlof (United States) — January 1987
Scientific Event Alert Network Bulletin, vol. 12, no. 1 (January 1987)
Managing Editor: Lindsay McClelland.
Pavlof (United States) Steam emission from two near-summit vents
Please cite this report as:
Global Volcanism Program, 1987. Report on Pavlof (United States). In: McClelland, L (ed.), Scientific Event Alert Network Bulletin, 12:1. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.SEAN198701-312030.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
Satellite images at 0514 and 1041 on 9 January show plumes drifting 150 and 100 km ESE from Pavlof. Between 17 January and 11 February, airplane crewmembers and observers at Cold Bay reported steaming from two near-summit vents (table 3).
Table 3. Summary of observations describing activity at Pavlof, 17 January-11 February 1987, collected by John Reeder.Observers (initials in brackets): Marsha Brown and Theresa Dubber, FAA, Cold Bay; Lee Goch, Don Munson, Janice Reeve Ogle, and James Fredenhagen, Reeve Aleutian Airways; Guy Morgan, Peninsula Airways.[Skip text table]
Date Time Activity Reported [Observers] 17 Jan 1546 Continuous steam emission from an upper NE-flank vent. [MB] 22 Jan 0953 Continuous steam emission from an upper NE-flank vent. [MB] 23 Jan Steam emission on SE flank. [TD] 26 Jan 1011 Steam emission from the NE vent. [MB] 31 Jan 1400 250-m steam plume from a upper SE-flank vent drifted about 5.5 km NW. [LG, DM, JO] 02 Feb 1300 150-m-high steam column from the SE vent. [LG & JF] 03 Feb 1400 150-m-high steam column from the NE vent drifted NE. [MB] 05 Feb 1000 Ash plume from summit drifted about 20 km WSW; several black flows (lava or debris) had extended at least 600 m down the NW slope. [MB] 11 Feb 1500 30-m steam plume from the NE vent; the summit was coverd with fresh snow. [MB]
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; Steve Shivers, USGS Anchorage.