Mount Gareloi

Coordinates: 51°47′18″N 178°47′39″W / 51.78833°N 178.79417°W / 51.78833; -178.79417
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Not to be confused with Gorely.
Mount Gareloi
Summit of the volcano
Highest point
Elevation5,161 ft (1,573 m)[1]
Prominence5,161 ft (1,573 m)[1]
Listing
Coordinates51°47′18″N 178°47′39″W / 51.78833°N 178.79417°W / 51.78833; -178.79417[1]
Geography
Gareloi is located in Alaska
Gareloi
Gareloi
Alaska
LocationGareloi Island, Alaska, U.S.
Parent rangeAleutian Islands
Geology
Age of rockHolocene-Pleistocene
Mountain typeStratovolcano
Volcanic arc/beltAleutian Arc
Last eruptionAugust 1989

Mount Gareloi, or Gareloi Volcano, is a

Anchorage. Gareloi is located on Gareloi Island, and comprises most of its land mass. The island also has two small glaciers which protrude to the northwest and southeast.[2]

The volcano is 6 miles (10 km) by 5 miles (8 km) at its base, possessing two summits. The southern crater is far greater in size, 984 feet (300 m) wide with fumaroles, which can be attributed to edifice failure in the southern wall, while Gareloi's northern crater is enclosed.

Discovery and accessibility

Kamchatka, where he started a settlement and built two additional vessels, dubbed St. Peter and St. Paul. In 1741 Bering and his company started towards North America, but were stalled by a storm and in being delayed were forced to take land. During the storm they could not make out the Alaskan coast. The storm proved too powerful so the ships turned around, along the way charting several of the Aleutians, including Gareloi.[3] Since then, it has been barely studied, resulting in a fragmentary knowledge of its eruptions and possibly even unrecorded episodes.[4]

Gareloi Island is uninhabited and is part of the Alaska Maritime National Wildlife Refuge managed by the U.S. Fish and Wildlife Service.[5]

Geography and geology

Gareloi is the northernmost volcano of the

sea cliffs on the southwest side of the island cut into the older caldera. Three masses offshore of the island were produced by debris flows from the volcano.[8]

Fissure created from Gareloi's 1929 eruption. This feature runs down the southern summit.

Gareloi is of lava flows and

Pleistocene took place.[7]

There are two large lava valleys on the island's southwest side which are u-shaped. The oldest of these flows are of Pleistocene age composed of

clinopyroxene, olivine, and hornblende.[6]

Rock

The rock that makes up Gareloi Island and its volcano is estimated to be of Pleistocene age.

dissected lava flows and pyroclastic masses, has been shaped by glacial retreat that began around 10,000 years past and fleshed out newly formed rocks. Other landslides have been generated on the north and east flanks of the volcano.[9]

Mapping

The Alaska Volcano Observatory proceeded to map the volcano and its surrounding area in 2003,[10] in addition to implementing seismic monitors in June.[11]

Eruptive history

Gareloi has an extensive eruptive history, dating back to at least 1760. At least 12 eruptions have occurred at the summit, accompanied by lava and

Volcanic Explosivity Index (VEI) of 1 to 3.[12] Such eruptions have occurred in 1790, 1791, 1792, 1873, 1922, April 1929, 1950, January 17, 1952, August 7, 1980, January 15, 1982, September 4, 1987, and August 17, 1989. Uncertain eruptions occurred in 1760, 1828, 1927, and 1996.[8]

1929

In 1929, Mount Gareloi underwent a major

explosive eruption where it generated four lava flows, andesitic tuff, volcanic glass, and scoria of red tone. Thirteen craters, all located in the fissure, contributed to this episode. All are most likely phreatic.[7] During the eruption, pyroclastic flows convened with tephra, as suggested by deposits. Lahar
also streamed from the summit.

1980s–1990s

On August 8, 1980 Gareloi erupted for the first time in records since 1929, sending ash plumes over 35,000 feet (10,668 m) into the atmosphere.

US Fish and Wildlife Service spotted another ash plume covering the caldera and climbing 2,300 feet (701 m) from the summit on August 17.[9] A minor eruption occurred on September 27, 1996 was reported to the National Weather Service Aviation Weather Unit in nearby Anchorage. The plume, consisting of ash and steam, rose 5,000 feet (1,524 m) from the volcano's summit.[9]

Threat

Proximal volcanic hazards pose a significant threat to human life near Gareloi. If Gareloi were to erupt unexpectedly, ash clouds, falling volcanic ash, pyroclastic flows, and debris avalanches (such as lahars) could easily spawn deadly hazards such as tsunamis. As volcanic ash can induce engine failure, it puts commercial airplanes in particular at high risk.[14] Inhalation of volcanic ash, also known as tephra, creates respiratory complexities and irritation of the eye.[15]

Pyroclastic flows from an eruption would destroy much wildlife about the volcano. Gareloi has historically produced several pyroclastic flows, which can travel extremely fast. Future flows at Mount Gareloi could travel off the island into the Pacific Ocean and, if large enough, could fall into the ocean and generate tsunamis, though unlikely.[15]

See also

References

  1. ^ a b c "Alaska & Hawaii P1500s - the Ultras". Peaklist.org. Retrieved 2013-01-31.
  2. ^ Alaska Volcano Observatory, Volcano Information -- Gareloi, Retrieved Dec. 16, 2022.
  3. ^ Chisholm, Hugh (1910). The Encyclopædia Britannica. Vol. 3. London. p. 775. {{cite encyclopedia}}: Missing or empty |title= (help)CS1 maint: location missing publisher (link)
  4. ^ Coombs, McGimsey and Browne, page 1.
  5. ^ Preliminary Volcano-Hazard Assessment for Gareloi Volcano, Gareloi Island, Alaska
  6. ^ a b Brandon Browne; Coombs, Michelle L.; Larsen, J. "Preliminary Geology of Gareloi Volcano, Western Aleutian Islands (Alaska)". United States Geological Survey. Archived from the original on March 15, 2009. Retrieved May 3, 2009.
  7. ^ a b c "Gareloi description and statistics". Alaska Volcano Observatory. Retrieved April 15, 2009.
  8. ^ a b c d "Gareloi". Global Volcanism Program. Smithsonian Institution. Retrieved April 13, 2009.
  9. ^ a b c d Coombs, McGimsey and Browne, page 9.
  10. ^ "Gareloi geologic, topographic, and location maps, as well as references that are classified as maps or that contain maps". Alaska Volcano Observatory. Retrieved May 3, 2009.
  11. ^ Neal, McGimsey, Dixon and Melnikov, page 1.
  12. ^ "Gareloi, Aleutian Islands, Alaska". Volcano World. Retrieved May 5, 2009.
  13. ^ a b c Coombs, McGimsey and Browne, page 8.
  14. ^ Coombs, McGimsey and Browne, page 14.
  15. ^ a b Coombs, McGimsey and Browne, page 15.

Sources

External links

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