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.

Geological Summary. The most active volcano of the Aleutian arc, Pavlof is a Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and Pavlof Sister to the NE form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that overlook Pavlof and Volcano bays. Little Pavlof is a smaller cone on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, eruptions have frequently been reported from Pavlof, typically 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 recorded 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.