Description: From Dixon and others (2015): "No eruptive activity occurred at Makushin Volcano in 2013, but increases in seismicity and reports of possible ash plumes prompted increased AVO attention. The Makushin seismograph network periodically recorded tremor episode during 2013, likely unrelated to volcanism. Short swarms of earthquakes are common near Makushin. Four such swarms were noted in the last one-half of the year on August 28, September 24, October 29, and December 25 (fig. 35 in original text). A single observation of a small steam plume was noted in a clear Web camera image of Makushin on March 24 (fig. 36 in original text). The Aviation Color Code and Volcano Alert Level remained GREEN/NORMAL throughout the year."