Report on Pavlof (United States) — 17 November-23 November 2021
Smithsonian Institution / US Geological Survey
Weekly Volcanic Activity Report, 17 November-23 November 2021
Managing Editor: Sally Sennert.
Please cite this report as:
Global Volcanism Program, 2021. Report on Pavlof (United States) (Sennert, S, ed.). Weekly Volcanic Activity Report, 17 November-23 November 2021. Smithsonian Institution and US Geological Survey.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
AVO reported that the eruption at Pavlof continued during 14-23 November and was focused at a vent on the upper NE flank. Seismicity remained elevated and signals were periodically recorded that were likely explosions. Lava fountaining began on 14 November and had built a small, unstable cone. Hot debris from the cone traveled a few hundred meters down the flanks, melting snow and ice that resulted in narrow lahars which traveled several kilometers down the flanks. Elevated surface temperatures were observed in satellite data at least through 23 November, suggesting that the lava fountaining continued. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.
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.