Isanotski

Photo of this volcano
  • United States
  • Alaska
  • Stratovolcano
  • Unknown - Evidence Uncertain
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 54.765°N
  • 163.723°W

  • 2446 m
    8023 ft

  • 311370
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Isanotski.

The Global Volcanism Program has no Weekly Reports available for Isanotski.

The Global Volcanism Program has no Bulletin Reports available for Isanotski.

Eruptive History


Summary of Holocene eruption dates and Volcanic Explosivity Indices (VEI).


Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
[ 1845 ] [ Unknown ] Uncertain    
[ 1831 Mar ] [ 1831 May 6 ± 1 days ] Uncertain    
[ 1830 Nov ] [ Unknown ] Uncertain 2  
[ 1825 Mar 10 ] [ Unknown ] Uncertain 4  
[ 1795 ] [ Unknown ] Uncertain 3  

This compilation of synonyms and subsidiary features may not be comprehensive. Features are organized into four major categories: Cones, Craters, Domes, and Thermal Features. Synonyms of features appear indented below the primary name. In some cases additional feature type, elevation, or location details are provided.

Photo Gallery


Three prominent volcanoes are constructed along an E-W line on the eastern half of Unimak Island. The aptly named Roundtop volcano in the lower foreground is glacially eroded and has had no historical eruptive activity. In the 1930s warm springs were found on its slopes. The recent discovery of Holocene pyroclastic-flow deposits and a group of lava domes south of Roundtop indicate it is still an active volcano. The glacially dissected Isanotski volcano and the beautifully symmetrical Shishaldin volcano are the prominent peaks behind Roundtop.

Photo by Clayton and Marcia Brown, 1986 (courtesy of John Reeder, Alaska Div. Geology Geophysical Surveys).
See title for photo information.
Three prominent stratovolcanoes are constructed along an E-W line on Unimak Island. Steaming Shishaldin, the highest of the three, rises to 2857 m in the foreground and is one of the most active volcanoes in the Aleutians. The dissected Isanotski volcano (right) has had reported eruptions of uncertain validity, and Roundtop volcano (center distance) has had Holocene eruptions, but no historical activity.

Photo by Clayton and Marcia Brown, 1987 (courtesy of John Reeder, Alaska Div. Geology & Geophysical Surveys).
See title for photo information.
Glaciers drape the ruggedly dissected upper flanks of Isanotski volcano and its dramatic summit pinnacles. Isanotski, locally known as Ragged Jack, is at the center of an E-W-trending group of three volcanoes on Unimak Island. Four poorly documented historical eruptions were noted in the 18th and 19th centuries. Some or all of these eruptions, however, could have been from neighboring Shishaldin volcano, and historical eruptions of Isanotski must be considered unlikely, given the extreme degree of erosional dissection.

Photo courtesy of Alaska Volcano Observatory, 1994.
See title for photo information.

Smithsonian Sample Collections Database


There are no samples for Isanotski in the Smithsonian's NMNH Department of Mineral Sciences Rock and Ore collection.

Affiliated Sites