Report on Pavlof (United States) — 12 June-18 June 2013
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 12 June-18 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, 12 June-18 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 were intermittent and minor during 12-14 June; ash plumes below an altitude of 6.1 km (20,000 ft) a.s.l. mostly drifted SE. Elevated surface temperatures consistent with lava effusion persisted until 1620 on 14 June. Seismicity decreased during 14-15 June. Minor emissions likely stopped, but web-camera views were cloudy. On 17 June no plumes were visible in satellite images, and web camera views showed mostly cloudy conditions. During 17-18 June seismic tremor amplitude increased slightly, and elevated surface temperatures consistent with lava effusion were detected in satellite images. A small ash plume rose from the crater. 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.