Event Name : Veniaminof 2018/09
|Start:||September 4, 2018 ||Observed|
|Lava flow: ||
|Tephra plume: ||
|ColHeight: ||4876 m ||
On September 3, 2018, AVO raised the Volcano Alert Level and Aviation Color Code at Veniaminiof from GREEN/Normal to YELLOW/Advisory, citing increased seisimic activity, including tremor. The next day, on September 4, 2018, AVO raised the levels again to ORANGE/Watch, because seismic activity increased and low-level pulsatory ash plumes from Veniaminof's summit were reported by residents of Perryville and observed in images from the FAA Perryville web camera. By Friday, September 14, a lava flow extended about 800 m (0.5 mi) down the south flank of the summit conoe. The lava flow was confined to the summit caldera. mages from an FAA Web camera in Perryville recorded incandescence at night and a gas plume has been visible sporadically, during clear daytime conditions. By September 28, the lava flow extended 900 m down the south flank of the summit cone. During the week of September 21 - 28, pilots reported lava fountaining and associated minor ash emissions that may have reached up to 15,000 ft asl but quickly dispersed downwind.
Low-level eruptive activity occurred at the intracaldera cone of Veniaminof volcano throughout October and November, indicated by relatively continuous seismic tremor, elevated surface temperatures and an eruption plume observed in satellite and web camera images. The eruption is characterized by low-level lava spattering, a lava flow, and variable emissions of steam and volcanic ash up to altitudes of 16,000 ft.
On November 21, 2018, AVO raised the aviation color code and volcano alert level at Veniaminof to RED/Warning, citing significant increase in ash emission and a plume to 15,000 ft asl, extending for more than 150 miles to the southeast. Observers in Perryville and webcam views indicated continuous ash emissions. By November 22, ash emissions had decreased and AVO lowered Veniaminof to ORANGE/Watch. Ash emissions continued, with a plume typically below 10,000 ft asl and extending as much as 100 km (60 miles) from the vent. Residents of Perryville reported trace ashfall on the morning of November 22. Low level eruptive activity including minor lava fountaining and a mixed plume of steam and volcanic ash continued through December.
In early January 2019, eruptive activity at Veniaminof paused or stopped, and AVO lowered Veniaminof to YELLOW/Advisory on January 4, 2019.
AVO continued to note elevated surface temperatures consistent with cooling lava through January, February, and March 2019, as well as intermittent low-level seismicity characterized by occasional low-frequency earthquakes and minor tremor.