Hazard Notification System (HANS) for Volcanoes


U.S. Geological Survey
Thursday, March 2, 2023, 9:20 AM AKST (Thursday, March 2, 2023, 18:20 UTC)

52°19'51" N 174°8'20" W, Summit Elevation 5030 ft (1533 m)
Current Volcano Alert Level: UNASSIGNED
Current Aviation Color Code: UNASSIGNED

Recent storm damage to regional telecommunications equipment in Atka, Alaska, has resulted in the loss of data flow from seismic stations located at the Atka volcanic complex. As a result, AVO can no longer seismically monitor the volcano. We are unable to assess whether the volcano is at its normal background state, or to quickly confirm or dismiss reports of activity there.

Because the Atka volcanic complex is not currently seismically monitored, the Aviation Color Code and Alert Level is being changed from GREEN/NORMAL to UNASSIGNED/UNASSIGNED. As at other volcanoes without real-time seismic monitoring, AVO will continue to use satellite and lightning data, regional infrasound, and reports from pilots and ground observers to detect signs of eruptive activity.

There is no estimate of when the telecommunications equipment will be repaired. AVO will issue additional information once data from the seismic network is available.

The Atka volcanic complex forms the northern part of Atka Island, located about 16 km north of the community of Atka and 1,761 km southwest of Anchorage. The Atka volcanic complex includes a possible older caldera and several younger vents, including Korovin Volcano, Mount Kliuchef, and Sarichef Volcano. Korovin Volcano, a 1553-m-high (5030 ft) stratovolcano, has been the site of most historical volcanic activity, and has a small, roiling crater lake that occasionally produces energetic steam emissions. Korovin has erupted several times in the past 200 years, including 1973, 1987, and 1998, and has likely had small ash emissions as recently as 2005. Typical recent Korovin eruptions produce minor amounts of ash and occasional but small lava flows. Reports of the height of the ash plume produced by the 1998 eruption ranged as high as 10,600 m (35,000 feet) above sea level. Mount Kliuchef is composed of a series of five vents aligned northeast–southwest. The two main summit vents of Kliuchef appear relatively young and the easternmost was probably the source of an 1812 eruption that is sometimes attributed to Sarichef.


Information on all Alaska volcanoes is available at: http://www.avo.alaska.edu.

For definitions of Aviation Color Codes and Volcano Alert Levels, see: http://www.avo.alaska.edu/color_codes.php

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Michelle Coombs, Scientist-in-Charge, USGS mcoombs@usgs.gov (907) 786-7497

David Fee, Coordinating Scientist, UAFGI dfee1@alaska.edu (907) 322-4085

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.