On 11 July, AVO noted that during the previous 24 hours a steam cloud from Pavlof was seen drifting SW by observers in Sand Point (90 km E) and by pilots flying near the volcano. Satellite images showed the cloud drifting 72 km SW. No unusual seismicity was detected. At 1300 the webcam recorded a minor ash emission rising tens of meters and drifting a few kilometers SW. The Aviation Color Code remained at Yellow and Volcano Alert Level remained at Advisory.

Geological Summary. The most active volcano of the Aleutian arc, Pavlof is a Holocene stratovolcano that was constructed along a line of vents extending NE from the Emmons Lake caldera. Pavlof and Pavlof Sister to the NE form a dramatic pair of symmetrical, glacier-covered stratovolcanoes that overlook Pavlof and Volcano bays. Little Pavlof is a smaller cone on the SW flank of Pavlof volcano, near the rim of Emmons Lake caldera. Unlike Pavlof Sister, eruptions have frequently been reported from Pavlof, typically 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 recorded 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.

Source: US Geological Survey Alaska Volcano Observatory (AVO)