Roundtop

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  • Country
  • Subregion Name
  • Primary Volcano Type
  • Last Known Eruption
  • 54.8°N
  • 163.589°W

  • 1871 m
    6137 ft

  • 311380
  • Latitude
  • Longitude

  • Summit
    Elevation

  • Volcano
    Number

There are no activity reports for Roundtop.



 Available Weekly Reports

There are no Weekly Reports available for Roundtop.

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

Start Date Stop Date Eruption Certainty VEI Evidence Activity Area or Unit
7600 BCE ± 500 years Unknown Confirmed 5 Tephrochronology

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. 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. Additional discussion of data sources can be found under Volcano Data Criteria.

Carson E C, Fournelle J H, Miller T P, Mickelson D M, 2002. Holocene tephrochonology of the Cold Bay area, southwest Alaska. Quat Sci Rev, 21: 2213-2228.

Fournelle J H, 1988. The geology and petrology of Shishaldin volcano, Unimak Island, Aleutian arc, Alaska. Unpublished PhD thesis, John Hopkins Univ, 507 p.

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..

Miller T P, 1999. Newly identified early Holocene caldera-forming druption from Roundtop volcano, Unimak Island, Alaska. Eos, Trans Amer Geophys Union, 1999 Fall Mtg, abs V51B-17.

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, 1975. Igneous-related geothermal systems. U S Geol Surv Circ, 726: 58-83.

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.

The flat-topped, glacier-covered Roundtop volcano is the easternmost and lowest of an E-W-trending line of volcanoes on eastern Unimak Island. Roundtop lies 13 km SW of the village of False Pass. The snow and ice-covered edifice fills much of a 3-km-wide caldera that formed during the early Holocene. The caldera-forming eruption produced pyroclastic flows and a rhyolitic tephra layer that is widespread throughout the southwestern end of the Alaska Peninsula. A group of lava domes was constructed south of Roundtop volcano. No historical eruptions are known from the 1871-m-high stratovolcano. In the 1930s warm springs were found on its slopes.