Semisopochnoi, United States
Semisopochnoi is a stratovolcano in the United States, 1,221 m (4,006 ft) high. Its last known eruption: 1964 or later. NOAA records no significant eruption here.
Semisopochnoi on the map
Semisopochnoi and the volcanoes within 300 km, colored by when each last erupted.
- Since 1964
- 1900 to 1963
- 1800s
- AD 1 to 1799
- Before AD 1, or undated
Now
From the USGS Volcano Hazards Program, read 15:32 UTC. USGS threat ranking: High Threat.
Normal / Green Alaska Volcano Observatory rates Semisopochnoi at alert level Normal, aviation color code Green, since 2026-02-27 20:55 UTC.
AVO Semisopochnoi GREEN/NORMAL - Small explosion on February 22. Volcano remains at GREEN/NORMAL.
The volcano
- Type
- Stratovolcano
- Elevation
- 1,221 m (4,006 ft)
- Country
- United States
- Region
- Aleutian Is
- Summit
- 51.930° N, 179.580° E
- Last known eruption
- 1964 or later
- Holocene activity known from
- Historical
- Smithsonian volcano number
- 311060
Significant eruptions
NOAA records eruptions that killed, did damage, were very large, or set off a tsunami or earthquake.
None on record.
Around it
The volcanoes within 300 km.
Earthquakes near SemisopochnoiVolcanic ash advisories on the live map
Sources
Volcanoes and significant eruptions from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. Alert levels, color codes and notices from the USGS Volcano Hazards Program and its observatories, public domain. Volcano numbers are the Smithsonian Institution’s Global Volcanism Program’s.