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United States · Caldera

Mount Aniakchak

Aniakchak

Type
Caldera
Elevation
1341m
Last eruption
1931
Mount Aniakchak
Photo: M. Williams, National Park Service · Public domain · Wikimedia Commons
Type
Caldera
Country
United States
Region
North America / Alaska Peninsula Volcanic Arc
Elevation
1341m
Coordinates
56.880, -158.170
Last eruption
1931
Tectonic setting
Subduction zone / Continental crust (> 25 km)
Landform
Caldera
Major rock type
Andesite / Basaltic andesite
Geological summary

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.

From Wikipedia

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.

Wikipedia · CC BY-SA · Read full article →

Eruption history

17 recordedGlossary
Summary (VEI over time)
Click a bar to see individual eruptions · Use arrow keys to move between bars, Enter to open
6300 BCE~6025 BCE · 1 eruptions · max VEI 66025 BCE~5751 BCE · 1 eruptions · max VEI ?2728 BCE~2454 BCE · 1 eruptions · max VEI ?1904 BCE~1630 BCE · 1 eruptions · max VEI 6531 BCE~256 BCE · 1 eruptions · max VEI ?19~294 · 1 eruptions · max VEI ?294~568 · 1 eruptions · max VEI ?568~843 · 1 eruptions · max VEI 0843~1118 · 1 eruptions · max VEI ?1118~1393 · 4 eruptions · max VEI ?1393~1667 · 2 eruptions · max VEI 41667~1942 · 2 eruptions · max VEI 46300 BCE4377 BCE2179 BCE256 BCE1667

Detailed timeline

  1. 1942VEI ?Method not stated
    1942-07-02 – end unknown
  2. 1931VEI 4Observed
    1931-05-01 – 1931-06-13
    West and SW caldera floor
  3. 1540 (±100 yrs)VEI 4Geological estimate
    1540 – end unknown
    NW & S caldera floor (Half Cone, Vent Mtn)
  4. 1470 (±20 yrs)VEI ?Geological estimate
    1470 – end unknown
    SE caldera floor (New Cone)
  5. 1370 (±55 yrs)VEI ?Geological estimate
    1370 – end unknown
    NW caldera floor (Half Cone)
  6. 1280 (±145 yrs)VEI ?Geological estimate
    1280 – end unknown
    NW caldera floor (Half Cone)
  7. 1190 (±30 yrs)VEI ?Geological estimate
    1190 – end unknown
    NW caldera floor (Half Cone)
  8. 1120 (±80 yrs)VEI ?Geological estimate
    1120 – end unknown
    East-central caldera (Surprise Cone)
  9. 1050VEI ?Geological estimate
    1050 – end unknown
    Vent Mtn and other vents?
  10. 700 (±250 yrs)VEI 0Geological estimate
    700 – end unknown
    S & NW caldera floor (Vent Mtn & Half Cone)
  11. 460VEI ?Geological estimate
    460 – end unknown
  12. 200 (±255 yrs)VEI ?Geological estimate
    200 – end unknown
    Northern & western caldera floor
  13. 370 BCE (±210 yrs)VEI ?Geological estimate
    370 BCE – end unknown
  14. 1645 BCE (±10 yrs)VEI 6Geological estimate
    1645 BCE – end unknown
  15. 2550 BCE (±500 yrs)VEI ?Geological estimate
    2550 BCE – end unknown
  16. 5930 BCE (±240 yrs)VEI ?Geological estimate
    5930 BCE – end unknown
  17. 6300 BCE (±1250 yrs)VEI 6Geological estimate
    6300 BCE – end unknown

Nearby volcanoes

External links

⚠ For reference only. Not for emergency response.