Alaska Volcano Observatory

From Dixon and others, 2017: "Mount Veniaminof had a 2-month-long period of increased seismic unrest in 2015. At the end of September, seismicity at Mount Veniaminof increased in the form of volcanic tremor and small low-frequency earthquakes. This type of activity was a known precursor to previous eruptions, most recently in 2009 (McGimsey and others, 2014) and 2013 (Dixon and others, 2015). On October 1, after the activity persisted for 1 day, the Aviation Color Code and Volcano Alert Level were raised to YELLOW/ADVISORY. Throughout October and early November, clear views from the Federal Aviation Administration (FAA) Perryville northwest web camera occasionally showed minor steam plumes issuing from the intracaldera cone (fig. 11[original text]). The intermittent, short bursts of seismic tremor persisted into November, indicating continued unrest. At the end of November, the seismic unrest at Veniaminof decreased to near background levels. On December 11, the Aviation Color Code and Volcano Alert Level was lowered to GREEN/NORMAL."