| Ukinrek maars | |
|---|---|
| Highest point | |
| Elevation | 299 ft (91 m) |
| Coordinates | 57°49′54″N 156°30′35″W / 57.83167°N 156.50972°W / 57.83167; -156.50972 |
| Geography | |
| Location | Becharof National Wildlife Refuge, Alaska, on Alaska Peninsula |
| Parent range | Aleutian Range |
| Geology | |
| Mountain type | Maars |
| Last eruption | March–April 1977 |
The Ukinrek maars (Central Yupik: Ukinrek) are two volcanic craters on the north side of the Aleutian Range in Alaska that were formed by a phreatomagmatic eruption in 1977. The maars are 1.5 km south of Becharof Lake and 12 km northwest of Peulik Volcano, on a low area of the range, bordering the Bering Sea. The western of the two is elliptical in shape and up to 170 m in diameter and 35 m deep. The other lies 600 m to the east and is circular and up to 300 m in diameter and 70 m deep. The east maar has a 49 m-high lava dome within its crater lake.
The eruption occurred in March–April 1977 and lasted for ten days. There was no previous eruption. The magmatic material was olivine basalt from a mantle source. Pyroclastic surge from the eruptions traveled to the northwest. The volume of lava erupted was 9×10 m and the volume of tephra expelled was 2.6×10 m. They were named shortly after the eruptions and the literal translation means "Two Holes".
The Quaternary age Gas Rocks dacite domes some three km to the northeast were the site of a phreatic eruption some 2300 years ago.
References
- ^ "Ukinrek Maars". Global Volcanism Program. Smithsonian Institution. Retrieved 2021-06-28.
- ^ Kienle, Juergen; Kyle, Philip; Self, Stephen; Motyka, Roman; Lorenz, Volker (February 1980). "Ukinrek Maars, Alaska, I. April 1977 eruption sequence, petrology and tectonic setting". Journal of Volcanology and Geothermal Research. 7 (1–2): 11. Bibcode:1980JVGR....7...11K. doi:10.1016/0377-0273(80)90018-9. Retrieved 1 May 2024.
- Miller, T.P., et al., 1998, Catalog of the historically active volcanoes of Alaska: U.S. Geological Survey Open-File Report 98-0582, 104 p
- "Ukinrek Maars: Eruptive History". Global Volcanism Program. Smithsonian Institution. Retrieved 2021-06-28.
- "Ukinrek Maars". Alaska Volcano Observatory. Retrieved 1 May 2024.
External links
- Volcanoes of the Alaska Peninsula and Aleutian Islands-Selected Photographs
- Alaska Volcano Observatory
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