| Mount Iliamna | |
|---|---|
 View of the glaciated north flank of Iliamna Volcano. A plume of steam and gas typically rises several hundred meters above thefumarole field. | |
| Highest point | |
| Elevation | 10,016 ft (3,053 m)[1] |
| Prominence | 7,867 ft (2,398 m)[2] |
| Listing | |
| Coordinates | 60°01′54″N153°05′28″W / 60.03167°N 153.09111°W /60.03167; -153.09111[3] |
| Naming | |
| Native name | Ch’naqał’in (Tanaina) |
| Geography | |
  Mount Iliamna Location in Alaska | |
 | |
| Interactive map of Mount Iliamna | |
| Location | Lake Clark National Park and Preserve |
| Country | United States |
| State | Alaska |
| Region | Kenai Peninsula Borough |
| Parent range | Chigmit Mountains,Aleutian Range |
| Topo map | USGS Lake Clark A-1 |
| Geology | |
| Formed by | Subduction zonevolcanism |
| Mountain type | Stratovolcano |
| Volcanic arc | Aleutian Arc |
| Last eruption | 1876 |
| Climbing | |
| First ascent | 1959 |
| Designated | 1976 |
Iliamna Volcano, orMount Iliamna (Dena'ina: Ch’naqał’in; Yupiaq:Puyulek), is aglacier-coveredstratovolcano in the largely volcanicAleutian Range in southwest Alaska. Located in theChigmit Mountain subrange inLake Clark National Park and Preserve, the 10,016-foot (3,053 m) volcano lies approximately 134 miles (215 km) southwest ofAnchorage on the west side of lowerCook Inlet. It is the 25th mostprominent peak in the United States.[1][2][4]
The volcano's glaciers have extensively altered its profile, cutting, deep and creating steep cliffs and cirques.[5] A ridge extends 5 kilometres (3.1 mi) south from the main body of the mountain, with North Twin and South Twin peaks along its length. There is no summit crater, only a zone of fumaroles just south of the summit at the top of large collapse zone at the head of Red Glacier, which exposes a cross section of the mountain.[6]
Holocene eruptive activity from Iliamna is little known, butradiocarbon dating seems to indicate at least a few eruptions, all before theEuropean settlement of Alaska. Prehistoric eruptions have been dated to 5050 and 2050 BCE (VEI-4), 450 BCE and 1650. Historically observed eruptions took place in 1867 (VEI-2) and 1876 (VEI-3), with unconfirmed eruptions in 1933, 1947, 1952 and 1953.[7] Fumaroles located at about 8,990 feet (2,740 m) elevation on the eastern flank produce nearly constant plumes of steam and minor amounts ofsulfurous gases. Theseplumes are quite vigorous and have resulted in numerouspilot reports and early historical accounts of "eruptions" at Iliamna Volcano. Earthquake swarms and elevated seismicity and gas emissions were reported in 1996-97 and 2011–13. Iliamna was ranked as a high-threat volcano by the U.S. Geological Survey in 2005 and 2018. The 2018 assessment ranked Iliamna as the 20th most hazardous volcano in the United States, up from 22nd, with an aviation threat score of 34 and an overall score of 115, the second highest of the "high threat" category.[8]
Major glaciers radiate from the summit of Iliamna,[6] includingRed Glacier,Tuxedni Glacier,Lateral Glacier andUmbrella Glacier.
Iliamna was first ascended in 1959.[2] It was designated aNational Natural Landmark in 1976.[9]
In July 2025, scientists reported vigorous seismic activity beneath Iliamna Volcano, which had been dormant for over a century. According to the Alaska Volcano Observatory (via NASA), the seismic tremors were significant enough to indicate renewed magma movement—although it was also noted that the quakes could result from an avalanche rather than an impending eruption.This marked the first notable unrest at Iliamna since the early 20th century[10]
This article incorporatespublic domain material from the United States Geological Survey
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