Report on Pavlof (United States) — 5 June-11 June 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 5 June-11 June 2013
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2013. Report on Pavlof (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 5 June-11 June 2013. 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 ash emissions from Pavlof that began on 4 June continued during 5-11 June, and were accompanied by seismic tremor and explosion signals. Overnight during 4-8 June satellite images detected elevated surface temperatures near the vent consistent with lava effusion and fountaining. On 5 and 6 June an ash plume observed in images drifted 40-45 km W and SW, at altitudes of 4.3-5.5 km (14,000-18,000 ft) a.s.l., based on pilot estimates. During 8-10 June images showed an ash plume drifting 20-53 km SE. The Volcanic Alert Level remained at Watch and the Aviation Color Code remained at Orange.
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.