Report on Pavlof (United States) — 20 July-26 July 2022
Smithsonian / US Geological Survey Weekly Volcanic Activity Report,
20 July-26 July 2022
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2022. Report on Pavlof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 20 July-26 July 2022. 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 a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 19-26 July. Seismic tremor persisted and multiple daily explosions were detected in seismic and infrasound data. Elevated surface temperatures were identified almost daily in satellite images; weather clouds sometimes prevented views. Diffuse ash emissions were visible in webcam images during 19-20 July. A low-level ash cloud that rose to 2.6 km (8,600 ft) a.s.l. was observed by a pilot at around 1150 on 22 July and corresponded to a slightly larger explosion detected in infrasound data. Steam emissions were visible in satellite images during 25-26 July. 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 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.