Report on Pavlof (United States) — 30 March-5 April 2016

Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 30 March-5 April 2016
Managing Editor: Sally Kuhn Sennert

Please cite this report as:

Global Volcanism Program, 2016. Report on Pavlof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 30 March-5 April 2016. Smithsonian Institution and US Geological Survey.

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Pavlof

United States

55.417°N, 161.894°W; summit elev. 2493 m

All times are local (unless otherwise noted)


AVO reported that the intensity of the eruption at Pavlof greatly decreased during 29-30 March, though a news article noted that ash from the eruption had caused more flights in and out of Yellowknife and Regina, Canada, to be cancelled. Elevated surface temperatures identified in satellite data and visual observations of low-level, intermittent ash plumes were noted during brief breaks in poor weather conditions. Seismicity remained elevated above background levels through 4 April, and was characterized by occasional short-duration tremor bursts. Cloud cover obscured satellite and web-cam views, though weakly elevated surface temperatures were detected in a few satellite images during 1-5 April. Airwave signals, indicative of small explosions at the summit, were recorded by the seismic stations at 1842 on 3 April. The Aviation Color Code remained at Orange and the Volcano Alert Level remained at Watch.

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.

Sources: US Geological Survey Alaska Volcano Observatory (AVO), CityNews