AVO reported that a minor eruption at a vent on Pavlof’s upper E flank was ongoing during 4-11 October. Seismic tremor continued. Strongly elevated surface temperatures were identified in satellite images during 5-6 October and incandescence was visible in nighttime webcam images. Discolored snow near the vent was visible in webcam views during the morning of 7 October suggesting low-level explosive activity; a small explosion was recorded at 1503 that same day though cloudy conditions prevented visual confirmation. Two small explosions were detected during 8-11 October. Very small ash emissions and lava near the vent were visible in occasional clear webcam images during 10-11 October. The Volcano Alert Level remained at Watch (the second highest level on a four-level scale) and the Aviation Color Code remained at Orange (the second highest level on a four-color scale).

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)