Isanotski

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  • 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.

Basic Data

Volcano Number

Last Known Eruption

Elevation

Latitude
Longitude
311370

Unknown - Evidence Uncertain

2446 m / 8023 ft

54.765°N
163.723°W

Volcano Types

Stratovolcano

Rock Types

Major
No Data (checked)

Tectonic Setting

Subduction zone
Continental crust (> 25 km)

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
0
44
372

Geological Summary

Rugged pinnacles form the summit of the deeply eroded Isanotski stratovolcano, locally known as Ragged Jack, at the center of an E-W-trending group of three volcanoes on eastern Unimak Island. Four poorly documented historical eruptions were noted in the 18th and 19th centuries. However, Miller et al. (1998) considered that some or all of these eruptions could have been from neighboring Shishaldin volcano and that historical eruptions of Isanotski must be considered unlikely, given the extreme degree of erosional dissection.

References

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography.

Coats R R, 1950. Volcanic activity in the Aleutian Arc. U S Geol Surv Bull, 974-B: 35-47.

IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..

Miller T P, McGimsey R G, Richter D H, Riehle J R, Nye C J, Yount M E, Dumoulin J A, 1998. Catalogue of the historically active volcanoes of Alaska. U S Geol Surv Open-File Rpt, 98-582: 1-104.

Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. Alaska Div Geol Geophys Surv, Prof Rpt, no 114, 17 p and 4 map sheets.

Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. U S Geol Surv Open-File Rpt, 78-925: 1-25.

Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.

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.


Synonyms

Issanakski | Sannak | Isannach | Ragged Jack | Isannachotski

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).
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).
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.

Smithsonian Sample Collections Database


A listing of samples from the Smithsonian collections will be available soon.

Affiliated Sites

Large Eruptions of Isanotski Information about large Quaternary eruptions (VEI >= 4) is cataloged in the Large Magnitude Explosive Volcanic Eruptions (LaMEVE) database of the Volcano Global Risk Identification and Analysis Project (VOGRIPA).
WOVOdat WOVOdat is a database of volcanic unrest; instrumentally and visually recorded changes in seismicity, ground deformation, gas emission, and other parameters from their normal baselines. It is sponsored by the World Organization of Volcano Observatories (WOVO) and presently hosted at the Earth Observatory of Singapore.
EarthChem EarthChem develops and maintains databases, software, and services that support the preservation, discovery, access and analysis of geochemical data, and facilitate their integration with the broad array of other available earth science parameters. EarthChem is operated by a joint team of disciplinary scientists, data scientists, data managers and information technology developers who are part of the NSF-funded data facility Integrated Earth Data Applications (IEDA). IEDA is a collaborative effort of EarthChem and the Marine Geoscience Data System (MGDS).
MODVOLC - HIGP MODIS Thermal Alert System Using infrared satellite Moderate Resolution Imaging Spectroradiometer (MODIS) data, scientists at the Hawai'i Institute of Geophysics and Planetology, University of Hawai'i, developed an automated system called MODVOLC to map thermal hot-spots in near real time. For each MODIS image, the algorithm automatically scans each 1 km pixel within it to check for high-temperature hot-spots. When one is found the date, time, location, and intensity are recorded. MODIS looks at every square km of the Earth every 48 hours, once during the day and once during the night, and the presence of two MODIS sensors in space allows at least four hot-spot observations every two days. Each day updated global maps are compiled to display the locations of all hot spots detected in the previous 24 hours. There is a drop-down list with volcano names which allow users to 'zoom-in' and examine the distribution of hot-spots at a variety of spatial scales.
MIROVA Middle InfraRed Observation of Volcanic Activity (MIROVA) is a near real time volcanic hot-spot detection system based on the analysis of MODIS (Moderate Resolution Imaging Spectroradiometer) data. In particular, MIROVA uses the Middle InfraRed Radiation (MIR), measured over target volcanoes, in order to detect, locate and measure the heat radiation sourced from volcanic activity.