Mount Shishaldin

Shishaldin Volcano, or Mount Shishaldin (), is a moderately active volcano on Unimak Island in the Aleutian Islands chain of Alaska in the United States.Alaska Volcano Observatory, Volcano Information -- Shishaldin
Retrieved Dec. 16, 2022. It is the highest mountain peak of the Aleutian Islands. The volcano's topographic contour lines are nearly perfect circles above . The lower north and south slopes are somewhat steeper than the lower eastern and western slopes. The volcano is the westernmost of three large stratovolcanoes along an east–west line in the eastern half of Unimak Island.

The upper is almost entirely covered by glacial snow and ice. In all, Shishaldin's glacial shield covers about . It is flanked to the northwest by 24 monogenetic parasitic cones, an area blanketed by massive lava flows. The Shishaldin cone is less than 10,000 years old and is constructed on a glacially eroded remnant of an ancestral somma and shield. Remnants of the older ancestral volcano are exposed on the west and northeast sides at elevation. The Shishaldin edifice contains about of material. A very steady steam plume rises from its small summit crater which is about across and slightly breached along the north rim.

In 1967, Shishaldin Volcano was designated as a National Natural Landmark by the National Park Service.

Name

The Aleuts named the volcano ''Sisquk'' or ''Sisagux'', meaning "mountain which points the way when I am lost." The spelling ''Shishaldin'' comes from the Russian version, ''Шишалдина'', of the Aleut name.

Activity

This volcano has had many recorded eruptions during the 19th and 20th centuries, and a couple of reports of volcanic activity in the area during the 18th century may have referred to Shishaldin as well. Therefore, the volcano's entire recorded history is spotted with reports of activity. AVO has 24 confirmed eruptions at Shishaldin, making it the volcano with the third most confirmed eruptions (after Akutan and Pavlof). However, Shishaldin has the most eruptions (this means confirmed ''and'' possible eruptions) in Alaska, but half of the eruptions are unconfirmed. Recent, well-documented eruptions were in 1995–96 and 1999. Since the 1999 eruption, it has maintained seismic activity, typically having very low-magnitude volcanic earthquakes (most are below magnitude 1) every 1–2 minutes. During this period of non-eruptive seismic activity, it has been puffing steam, with puffs also occurring about every 1–2 minutes. There were reports in 2004 of small quantities of ash being emitted with the steam.

A new period of activity started in July 2019 with incandescence observed in the summit crater during a time of increased seismic activity. On July 23, an active lava lake and minor spattering within the summit crater was observed. A new lava effusion event began on October 13 advancing over the next several weeks. The summit cone partially collapsed on November 25, producing a pyroclastic flow down the northwest side of the volcano and a new lava flow. On December 12, a short-lived explosion from Shishaldin expelled an ash cloud to . During late December, eruptive activity continued with lava flows and low-level explosive activity at the summit. On January 3, 2020, seismicity led to an ash cloud eruption that reached as high as . Another large ash cloud was emitted on January 19, 2020. The lava flows emitted during the eruptive events have cut deep channels in the snow and ice mantle of the volcano's north slope.

The Alaska Volcano Observatory monitors the volcano for more hazardous activity with seismometers and satellite images. Due to the remote location of the volcano, visual observations are rare.

Climbing

The first recorded ascent of Shishaldin was in 1932, by G. Peterson and two companions. Given the straightforward nature of the climbing (Alaska Grade 1, snow up to 40 degree slope), it is possible that an earlier ascent occurred, either by native Aleuts, Russians, or other visitors. Shishaldin is a popular ski descent ( vertical) for local climbers (of whom there are few). Due to its remoteness, Shishaldin is not often climbed by outsiders.

Gallery

File:Mount Shishaldin at sunset.jpg, An image of the volcano at sunset from 2005
File:Shishaldin Volcano eruption 1999.jpg, A view of the volcano's 1999 eruption.
File:Map of Alaska Peninsula Volcanoes.gif, Map showing volcanoes of Alaska Peninsula.
File:Shishaldin Volcano, Alaska.jpg, An overhead view of the volcano from November 24, 2013
File:Shishaldin Isanotski.jpg, Shishaldin and Isanotski Volcanoes.
File:Line4537 - Flickr - NOAA Photo Library.jpg, Shishaldin (left) and Isanotski volcanoes on Unimak Island.
File:Line6680 (19783395131).jpg, Shishaldin Volcano on the west end of Unimak Island.

See also

*List of mountain peaks of North America
**List of mountain peaks of the United States
***List of mountain peaks of Alaska
*List of Ultras of the United States
*List of volcanoes in the United States

Further reading

* Finch, Ruy Herbert, 1934, "Shishaldin Volcano: Proceedings of the Fifth Pacific Science Conference, Canada", ''Proceedings - Pacific Science Conference'' v. 3, pp. 2369–2376
* Fournelle, John Harold, 1988, ''The geology and petrology of Shishaldin Volcano, Unimak Island, Aleutian Arc, Alaska'', Ph.D. thesis Johns Hopkins University

References

External links

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Volcanoes of the Alaska Peninsula and Aleutian Islands-Selected Photographs

Alaska Volcano ObservatoryShishaldin webcam

* Michael Wood and Colby Coombs, ''Alaska: a climbing guide'', The Mountaineers, 2001.

{{DEFAULTSORT:Shishaldin, Mount
Mountains of Aleutians East Borough, Alaska
Active volcanoes
Stratovolcanoes of the United States
Mountains of Alaska
Volcanoes of Alaska
National Natural Landmarks in Alaska
[ ategory:Aleutian Range
Shishaldin
Holocene stratovolcanoes