Yunaska

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  • United States
  • Alaska
  • Shield
  • 1937 CE
  • Country
  • Volcanic Region
  • Primary Volcano Type
  • Last Known Eruption
  • 52.643°N
  • 170.629°W

  • 550 m
    1804 ft

  • 311210
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

The Global Volcanism Program has no activity reports for Yunaska.

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

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

The elongated, 9 x 23 km island of Yunaska in the Islands of the Four Mountains group is comprised of two unnamed volcanic centers of greatly different morphology. The older, 950-m-high western center consists of the eroded remnants of four overlapping stratovolcanoes that form a linear, NNE-trending ridge. Cinder cones and fissure-fed lava flows extend from the western end of the complex. The younger, 550-m-high eastern complex consists of a shield volcano capped by two nested calderas. The 3.5-km-wide Coats caldera is located within an older 10 x 13 km caldera and contains cinder cones and a lava field. Two areas of particularly youthful lava flows extend down the flank through a gap in the SW caldera rim and blanket the upper northern flank of the caldera. Vents are found on the flanks of the caldera within a kilometer of its rim. A post-caldera cone is capped by a small summit crater. The eastern center is presumably the source of the island's historical eruptions, first recorded in 1817.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
1937 Nov 3 1937 Nov 4 Confirmed 3 Historical Observations
[ 1929 ] [ Unknown ] Uncertain    
[ 1873 ] [ Unknown ] Uncertain 2  
1830 Unknown Confirmed 2 Historical Observations
1824 Unknown Confirmed 3 Historical Observations
[ 1817 ] [ Unknown ] Uncertain    

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.



Craters
Feature Name Feature Type Elevation Latitude Longitude
Coats Caldera Caldera
The rim of the summit caldera of Yunaska volcano is seen from an older volcanic center on the western side of the island. The younger, 550-m-high eastern complex consists of a shield volcano capped by two nested calderas and is presumably the source of the island's historical eruptions, first recorded in 1817. A young lava flow at the far right descended through a notch in the caldera rim. In the background are the snow-capped peaks (left-to-right) of Carlisle, Cleveland, and Herbert volcanoes.

Photo by Jim Meyers, 1992 (University of Wyoming, courtesy of Alaska Volcano Observatory).

The following references have all been used during the compilation of data for this volcano, it is not a comprehensive bibliography. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title.

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

Henning R A, Rosenthal C H, Olds B, Reading E (eds), 1976. Alaska's volcanoes, northern link in the ring of fire. Alaska Geog, 4: 1-88.

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

Lamb D, Linneman S R, Myers J D, Nicolaysen K E, 1992. Caldera formation on Yunaska Island, central Aleutian arc (abs). Eos, Trans Amer Geophys Union, 73: 645.

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.

Myers J D, 1994. The Geology, Geochemistry and Petrology of the recent Magmatic Phase of the Central and Western Aleutian Arc. Unpublished manuscript, unpaginated.

Nicolaysen K E, Myers J D, Linneman S R, Lamb D, 1992. Geologic relations of the Yunaska volcanic complex, central Aleutian arc (abs). Eos, Trans Amer Geophys Union, 73: 645.

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.

Volcano Types

Shield
Caldera(s)
Pyroclastic cone(s)

Tectonic Setting

Subduction zone
Intermediate crust (15-25 km)

Rock Types

Major
Andesite / Basaltic Andesite
Basalt / Picro-Basalt
Dacite

Population

Within 5 km
Within 10 km
Within 30 km
Within 100 km
0
0
0
0

Affiliated Databases

Large Eruptions of Yunaska 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).
Smithsonian Collections Search the Smithsonian's NMNH Department of Mineral Sciences collections database. Go to the "Search Rocks and Ores" tab and use the Volcano Name drop-down to find samples.