Alaska Volcano Observatory | Kupreanof Alaska Volcano Observatory Home Volcanoes Webcams Webcams Ashcam GUI News Explore Data Explore Data References Webicorder Hazard Alert System Eruptions Geochem Locations Glossary Images Get Involved About AVO About AVO Staff Study Areas Alert Levels FAQ Kupreanof Description Current Activity Past Activity Images Maps Bibliography Prepare Ash Forecasting Facts Official Name: Mount Kupreanof Seismically Monitored: No Color Code: YELLOW Alert Level: ADVISORY Elevation: 1895m (6217ft) Latitude: 56.0126 Longitude: -159.7912 Smithsonian VNum: 312060 Pronunciation: Your browser does not support the audio element. Nearby Towns: Ivanof Bay 14 mi (22 km) SE Perryville 26 mi (42 km) SE Chignik Lake 43 mi (69 km) NE Chignik Lagoon 53 mi (85 km) NE Sand Point 54 mi (87 km) SW Distance from Anchorage: 505 mi (813 km) Description From Wood and Kienle (1990) [1] : "The Stepovak Bay group is a chain of five volcanoes at the southwest end of a N40E oriented linear segment of the Aleutian arc on the Alaska Peninsula. This same segment includes the better known Veniaminof and Aniakchak calderas. Three of the Stepovak Bay volcanoes (2, 4, and Kupreanof) have clearly had Holocene eruptions, resulting in three small debris flows filling late Pleistocene glacial valleys, and a small cinder cone and associated lava flow. The other two volcanoes (1 and 3) do not show unmistakable evidence of Holocene activity. They have ice-filled summit craters 500 m (1) and 300 m (3) in diameter that may be late Pleistocene age. These volcanoes have contributed to extensive late Tertiary and Quaternary lava flows, some extending near sea level. "Kupreanof is the largest and best known volcano of the group. In 1982, reconnaissance mapping located the three southernmost volcanoes. Later work further delineated these three, and located an additional center (4). Mapping and K-Ar dating indicate the area has been the locus of voluminous volcanic activity for approximately the last 4 million years. A fumarole occurs at Kupreanof volcano; another has been reported on volcano 4. Air photos from the late 1940s also suggest the presence of a fumarole on volcano 1. "Northwest of the line of volcanoes a projected fault vertically offsets the volcanoes from flows that are related to the early history of the centers. These flows, which dip away from the centers, yield K-Ar ages between 3.9 and 1.7 Ma. Along the trend, and 7 to 12 km southwest of the volcanoes, is another area of early (?) Quaternary flows possibly related to a yet unrecognized center; outcrops of hypabyssal rocks in a snowfield among these flows may be this center. The group of volcanoes overlies sedimentary rocks of Oligocene to late Miocene age; the southern centers also overlie thick tuff deposits of uncertain but presumably late Tertiary or early Quaternary age." References Cited [1] Volcanoes of North America: United States and Canada, 1990 Wood, C. A., and Kienle, Juergen, (eds.), 1990, Volcanoes of North America: United States and Canada: New York, Cambridge University Press, 354 p. Current Activity August 12, 2026, 1:25 pm Low-level earthquake activity continued over the past day. No activity was observed in cloudy satellite and webcam images. A new temporary monitoring station was installed recently near Mount Kupreanof and is providing seismic data, infrasound data, gas measurements, and web camera images on an intermittent basis. This is by design to conserve battery power, but the frequency of data acquisition can be increased if activity warrants. The closest functioning seismometers that provide continuous data are approximately 10 miles (16 km) to the northeast of the volcano as part of the Mount Veniaminof network. Mount Kupreanof is also monitored by satellite data, remote infrasound and lightning networks, and visual observations from pilots and mariners passing by the volcano. Recent Updates Low-level seismic activity continued over the past day. Aug 12th, 2026 01:25:34 PM Low-level seismic activity continued over the past day. Sulfur dioxide emissions detected in satellite data. Aug 11th, 2026 01:01:29 PM Low-level seismic activity continued over the past day. Sulfur dioxide emissions detected in satellite data. Aug 10th, 2026 01:15:54 PM Low-level seismic activity continued over the past day. Aug 9th, 2026 09:09:04 AM Low-level seismic activity continued over the past day. Aug 8th, 2026 09:53:21 AM Webcams Kupreanof [KUSW, 1791 ft] Color Code Timeline An explanation of color codes and alert levels can be found here. Loading Past Activity... Loading Images... Loading Maps... Loading Bibliography... Before an eruption Sign up for volcanic activty alerts from the Volcano Notification System (US Geological Survey) Ashfall & Preparedness Information Ashfall impacts & preparedness (US Geological Survey) Volcanic health hazards & impacts (International Volcanic Health Hazards Network) Ash Alert! Pamphlet (AK Division of Homeland Security & Emergency Management) Volcanic Ashfall (AK Department of Environmental Conservation, Division of Air Quality) During and After an Eruption National Weather Service Ashfall Warnings are posted here when in effect Alaska Division of Homeland Security and Emergency Management Ted Stevens Airport Flight Status (Anchorage) Fairbanks Airport Flight Status Other Useful Links Citizen Science: Ashfall collection instructions Citizen Science: IS ASH FALLING? Report your observations (yes or no!) Ash Forecasting Mathematical models developed by the USGS forecast various aspects of how a volcanic ash plume will interact with wind—where, how high, and how fast ash particles will be transported in the atmosphere, as well as where ash will fall out and accumulate on the ground. AVO runs these models when a volcano is restless by assuming a reasonable hypothetical eruption, to provide a pre-eruptive forecast of areas likely to be affected. During an ongoing eruption, AVO will update the forecast with actual observations (eruption start time and duration, plume height) as they become available. View the current airborne ash cloud models for Kupreanof Ashfall thickness forecast The Ash3d model was developed by the USGS to forecast how a volcanic ash plume will interact with wind and where ash will fall out and accumulate on the ground. AVO runs these models twice daily when a volcano is restless by assuming a reasonable hypothetical eruption altitude and duration. The map shows the model results of ashfall thickness for areas that are likely to be affected, if one were to occur. During an ongoing eruption, AVO will update the forecast with actual observations (eruption start time and duration, plume height) as they become available, and these plots will be automatically updated. The National Weather Service Anchorage Forecast Office will issue the official ashfall warning product and post them at weather.gov/afc THESE PRODUCTS MAY NOT BE CURRENT. During an actual eruption, see National Weather Service forecasts of ashfall:https://weather.gov/afc. Ashfall Forecast Click on the X on the graphic (upper right) to expand the map to show the map legend. Ashfall Start Time This map shows the modeled estimate of the time it would take for ashfall to begin following an eruption. It corresponds to the ashfall thickness forecast map shown above. This map uses the start time of either the twice-daily hypothetical model runs (time shown in the legend) or the actual eruption start time (if one were to occur). In the case of an actual eruption, the National Weather Service Anchorage Forecast Office will issue the official ashfall warning product that includes the ashfall start time and post them at weather.gov/afc THESE PRODUCTS MAY NOT BE CURRENT. During an actual eruption, see National Weather Service forecasts of ashfall:https://weather.gov/afc. Ashfall Start Times Forecast Click on the X on the graphic (upper right) to expand the map to show the map legend. USGS Volcano Notification Service Contact AVO Privacy Accessibility Information Quality FOIA This website is supported by the U.S. Geological Survey under Cooperative Agreement Grant G22AC00137 and G23AC00070. Mention of trade names or commercial products does not constitute their endorsement by the U.S. Geological Survey. ×