Report on Pavlof (United States) — April 1976

Natural Science Event Bulletin, vol. 1, no. 7 (April 1976)
Managing Editor: David Squires.

Pavlof (United States) Steam-and-ash emissions; ashfall seen on flanks

Please cite this report as:

Global Volcanism Program, 1976. Report on Pavlof (United States). In: Squires, D (ed.), Natural Science Event Bulletin, 1:7. Smithsonian Institution. http://dx.doi.org/10.5479/si.GVP.NSEB197604-312030.

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Pavlof

United States

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

All times are local (unless otherwise noted)


6 April, 1118: pilot reported ash extensively covering entire expanse of Pavlof's SE flank. Black smoke and intermittent steam were observed. 14 April, 0900-1900: steaming intermittently; 2 ash sprays visible on NW flank. 15 April, 0600-0700; 25 April 2300; and 27 April 1200-1900: steam emissions. 29 April, 1500: a pilot reported the volcano steaming. The entire E flank was reported to be ash-covered and very black. 30 April, 1200-1900: Although difficult to differentiate between ash and exposed rock (when viewed from Cold Bay, 60 km to the W) there appeared to be ash over the upper 100 m of the cone and along several radial areas along the near (SW) flank. Pavlof apparently produced extensive ash during the last few days of the month.

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.

Information Contacts: P. Sventek, USAF, Cold Bay.