Report on Pavlof (United States) — 7 July-13 July 2021
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
7 July-13 July 2021
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2021. Report on Pavlof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 7 July-13 July 2021. Smithsonian Institution and US Geological Survey.
55.417°N, 161.894°W; summit elev. 2493 m
All times are local (unless otherwise noted)
At 1140 on 9 July AVO raised the Volcano Alert Level and Aviation Color Code at Pavlof to Advisory and Yellow, respectively, noting that seismicity had increased during the previous 16 hours and was characterized by near-continuous tremor. Seismicity decreased and was more periodic during 10-13 July, but remained above background levels.
Geological Summary. 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.