AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 16-23 August. There was no evidence of lava effusion, but seismic tremor persisted and multiple small explosions were detected on most days in local seismic, regional seismic, and infrasound data. During 17-18 August explosions produced minor ash emissions that rose to 3 km (10,000 ft) a.s.l. and dissipated quickly, as reported by pilots and seen in webcam images. Daily elevated surface temperatures were identified in satellite images reflecting a hot vent. The Volcano Alert Level remained at Watch and the Aviation Color Code remained at Orange.

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)