Report on Pavlof (United States) — 14 June-20 June 2017
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 14 June-20 June 2017
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2017. Report on Pavlof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 14 June-20 June 2017. 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 seismicity at Pavlof had declined since the small increase on 7 June, and no unusual activity was observed in seismic or infrasound data through 20 June. Minor steam emissions occasionally rose from the summit crater. Satellite images showed an approximately 55 km-long steam plume drifting W on 14 June, and a thermal anomaly during 15-16 and 20 June. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory.
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.