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Mount Aniakchak

Aniakchak

Caldera · United States · 1341 m

Aniakchak is a 10-km-wide summit caldera containing numerous cones, lava domes, and lava flows on the caldera floor. The largest intra-caldera cone is Vent Mountain that reaches 430 m in height and has a diameter at the base of 2.5 km. At least 20 Holocene eruptions may have occurred before the Aniakchak II caldera-forming eruption.
Aniakchak is a 10-km-wide summit caldera containing numerous cones, lava domes, and lava flows on the caldera floor. The largest intra-caldera cone is Vent Mountain that reaches 430 m in height and has a diameter at the base of 2.5 km. At least 20 Holocene eruptions may have occurred before the Aniakchak II caldera-forming eruption. · Foto: Photo by M. Woodbridge Williams (National Park Service). · Wikimedia Commons
Tipo
Caldera
Paese
United States
Regione
North America Volcanic Regions / Alaska Peninsula Volcanic Arc
Altitudine
1341 m
Coordinate
56.880, -158.170
Ultima eruzione
1931
Contesto tettonico
Subduction zone / Continental crust (> 25 km)
Forma vulcanica
Caldera
Roccia principale
Andesite / Basaltic Andesite
Sintesi geologica

One of the most dramatic calderas of the Aleutian arc, the 10-km-wide Aniakchak caldera formed around 3,400 years ago during a voluminous eruption in which pyroclastic flows traveled more than 50 km N to the Bering Sea and also reached the Pacific Ocean to the south. At least 40 explosive eruptions have been documented during the past 10,000 years, making it the most active volcano of the eastern Aleutian arc. A dominantly andesitic pre-caldera volcano was constructed above basement Mesozoic and Tertiary sedimentary rocks that are exposed in the caldera walls to elevations of about 610 m. The ice-free caldera floor contains many pyroclastic cones, tuff cones, maars, and lava domes. Surprise Lake on the NE side drains through The Gates, a steep-walled breach on the east side of the 1-km-high caldera rim that was the site of catastrophic draining of a once larger lake about 1850 years BP. Vent Mountain and Half Cone are two long-lived vents on the south-central and NW caldera floor, respectively. The first and only confirmed historical eruption took place in 1931 from vents on the west and SW caldera floor.

Sintesi da Wikipedia

Riassunto in inglese

Mount Aniakchak is a volcano on the western Alaska Peninsula. Part of the Aleutian Volcanic Arc, it was formed by the subduction of the oceanic Pacific Plate under the North American Plate. Aniakchak is a 10 kilometers (6.2 mi) wide caldera with a break to the northeast. The caldera contains Surprise Lake and many volcanic cones, maars and craters, including Vent Mountain. The volcano has erupted mainly calc-alkaline rocks ranging from basalt to rhyolite.

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Storia delle eruzioni

Riepilogo (VEI nel tempo)
Fai clic su una barra per vedere le singole eruzioni
6300 BCE~6025 BCE · 1 eruzioni · VEI max. 66025 BCE~5751 BCE · 1 eruzioni · VEI max. ?2728 BCE~2454 BCE · 1 eruzioni · VEI max. ?1904 BCE~1630 BCE · 1 eruzioni · VEI max. 6531 BCE~256 BCE · 1 eruzioni · VEI max. ?19~294 · 1 eruzioni · VEI max. ?294~568 · 1 eruzioni · VEI max. ?568~843 · 1 eruzioni · VEI max. 0843~1118 · 1 eruzioni · VEI max. ?1118~1393 · 4 eruzioni · VEI max. ?1393~1667 · 2 eruzioni · VEI max. 41667~1942 · 2 eruzioni · VEI max. 46300 BCE4377 BCE2179 BCE256 BCE1667

Cronologia dettagliata

  1. 1942VEI ?Stima geologica
    1942 – In corso
  2. 1931VEI 4Osservata
    1931-05-01 – 1931-06-13
    West and SW caldera floor
  3. 1540 (±100 anni)VEI 4Stima geologica
    1540 – In corso
    NW & S caldera floor (Half Cone, Vent Mtn)
  4. 1470 (±20 anni)VEI ?Stima geologica
    1470 – In corso
    SE caldera floor (New Cone)
  5. 1370 (±55 anni)VEI ?Stima geologica
    1370 – In corso
    NW caldera floor (Half Cone)
  6. 1280 (±145 anni)VEI ?Stima geologica
    1280 – In corso
    NW caldera floor (Half Cone)
  7. 1190 (±30 anni)VEI ?Stima geologica
    1190 – In corso
    NW caldera floor (Half Cone)
  8. 1120 (±80 anni)VEI ?Stima geologica
    1120 – In corso
    East-central caldera (Surprise Cone)
  9. 1050VEI ?Stima geologica
    1050 – In corso
    Vent Mtn and other vents?
  10. 700 (±250 anni)VEI 0Stima geologica
    700 – In corso
    S & NW caldera floor (Vent Mtn & Half Cone)
  11. 460VEI ?Stima geologica
    460 – In corso
  12. 200 (±255 anni)VEI ?Stima geologica
    200 – In corso
    Northern & western caldera floor
  13. 370 a.C. (±210 anni)VEI ?Stima geologica
    BCE 370 – In corso
  14. 1645 a.C. (±10 anni)VEI 6Stima geologica
    BCE 1645 – In corso
  15. 2550 a.C. (±500 anni)VEI ?Stima geologica
    BCE 2550 – In corso
  16. 5930 a.C. (±240 anni)VEI ?Stima geologica
    BCE 5930 – In corso
  17. 6300 a.C. (±1250 anni)VEI 6Stima geologica
    BCE 6300 – In corso

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