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, July 31, 2021, 10:19 AM AKDT
Alaska Volcano Observatory
N 51 deg 55 min E 179 deg 35 min
2625 ft (800 m)
Volcanic Activity Summary: Seismic activity at Semisopochnoi has increased in recent days with a marked increase in the past 8 hours. Increased activity has also been detected on local infrasound stations, suggesting possible low-level (below 10,000 ft above sea level) emissions. Due to this increase in activity, AVO is raising the Aviation Color Code to ORANGE and the Alert Level to WATCH.
When occurring, small eruptions producing minor ash deposits within the vicinity of the active north crater of Mount Cerberus and ash clouds under 10,000 ft above sea level are typical of activity at Semisopochnoi.
[Volcanic cloud height] none
[Other volcanic cloud information] none
[Ash cloud] none
[Volcanic gas] SO2 emissions detected on occasion
Semisopochnoi is monitored by a local seismic and infrasound network, local web cameras, regional lightning and infrasound sensors, and satellite data.
Matt Haney, Acting Scientist-in-Charge, USGS firstname.lastname@example.org (907) 786-7497
David Fee, Coordinating Scientist, UAF email@example.com (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 http://www.avo.alaska.edu
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.