Mount Shishaldin

Mount Shishaldin
Mount Shishaldin, May 1994
Highest point
Elevation	9,373 ft (2,857 m)
Prominence	9,373 ft (2,857 m)
Isolation	877 km (545 mi)
Listing	Highest ocean islands 28th World prominent peaks 115th North America prominent 20th North America isolated peak 10th
Coordinates	54°45′21″N 163°58′03″W / 54.75583°N 163.96750°W / 54.75583; -163.96750
Geography
Mount Shishaldin Unimak Island, Alaska, U.S.
Parent range	Aleutian Range
Topo map	USGS False Pass D-6
Geology
Mountain type	Stratovolcano
Volcanic arc/belt	Aleutian Arc
Last eruption	2023
Climbing
First ascent	May 16, 1932 by G. Peterson et al. (first recorded ascent)
Easiest route	East face:snow/glacier climb
U.S. National Natural Landmark
Designated	1967

Shishaldin Volcano, or Mount Shishaldin (/ʃɪˈʃældən/), is a moderately active volcano on Unimak Island in the Aleutian Islands chain of Alaska in the United States.^[1] It is the highest mountain peak of the Aleutian Islands and rises about 10,000m (33,000 ft) from the bottom of the Aleutian Trench 140 miles south of the volcano. The volcano's topographic contour lines are nearly perfect circles above 6,500 feet (1,981 m). The lower north and south slopes are somewhat steeper than the lower eastern and western slopes. Only on the volcano's west flank between about 3500 to 6500 ft are small areas of rough topography which are remnants of an older collapsed volcano upon which Shishaldin is built. The volcano is the westernmost of three large stratovolcanoes along an east–west line in the eastern half of Unimak Island.

The upper 6,600 ft (2,012 m) is almost entirely covered by glacial snow and ice. In all, Shishaldin's glacial shield covers about 35 square miles (91 km²). 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 4,900 to 5,900 ft (1,494 to 1,798 m) elevation. The Shishaldin edifice contains about 300 cubic kilometers (72 cubic miles) of material. A very steady steam plume rises from its small summit crater which is about 500 ft (152 m) across and slightly breached along the north rim. In appearance, the volcano can vary from nearly completely white to almost all black, depending on the occurrence of ashfall deposits.

In 1967, Shishaldin Volcano was designated as a National Natural Landmark - the Shishaldin Volcano National Natural Landmark - by the National Park Service. The landmark is 62,714 acres and a plaque was erected near the coast.^[2]