Printer friendly versionAVO/USGS Volcanic Activity Notice
Current Volcano Alert Level: WATCH
Previous Volcano Alert Level: ADVISORY
Current Aviation Color Code: ORANGE
Previous Aviation Color Code: YELLOW
Saturday, February 15, 2020, 12:19 AM AKST
Alaska Volcano Observatory
N 51 deg 55 min E 179 deg 35 min
2625 ft (800 m)
Volcanic Activity Summary: A series of small explosions and tremor bursts have been detected in seismic data at Semisopochnoi over the past 7 hours and are continuing, representing a significant uptick in activity. No ash plumes have been observed, however low-level ash emissions may accompany these minor explosions. Any ash emissions may be currently obscured by cloud cover at ~10,000 ft. The Alaska Volcano Observatory is therefore raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.
[Volcanic cloud height] No cloud observed
[Other volcanic cloud information] No cloud observed
Semisopochnoi is monitored with an on-island seismic network, and remotely by satellite and lightning sensors. An infrasound array on Adak Island could detect explosive emissions from Semisopochnoi with a 13 minute delay if atmospheric conditions permit.
Michelle Coombs, Scientist-in-Charge, USGS
email@example.com (907) 786-7497
Taryn Lopez, Acting Coordinating Scientist, UAFGI
firstname.lastname@example.org (907) 322-4085
A new VAN will be issued if conditions change significantly or alert levels are modified. While a VAN is in effect, regularly scheduled updates are posted at
The Alaska Volcano Observatory is a cooperative program of the U.S. Geological Survey, the University of Alaska Fairbanks Geophysical Institute, and the Alaska Division of Geological and Geophysical Surveys.