Jump to content

Ukinrek maars

From Wikipedia, the free encyclopedia

This is an old revision of this page, as edited by Iridescent (talk | contribs) at 17:25, 7 November 2016 (top: Typo fixing, typo(s) fixed: April of 1977 → April 1977 using AWB). The present address (URL) is a permanent link to this revision, which may differ significantly from the current revision.

Ukinrek Maars
Map
Highest point
Elevation299 ft (91 m)
Coordinates57°49′54″N 156°30′35″W / 57.83167°N 156.50972°W / 57.83167; -156.50972[1]
Geography
LocationBecharof National Wildlife Refuge, Alaska, on Alaska Peninsula
Parent rangeAleutian Range
Geology
Mountain typeMaars
Last eruptionMarch to April 1977

The Ukinrek Maars are two phreatomagmatic vents that formed on the north side of the Aleutian Range on a low area bordering the Bering Sea. The maars are 1.5 km south of Becharof Lake and 12 km northwest of Peulik Volcano. The western of the two is elliptical in shape and up to 170 m in diameter and 35 m deep. The east maar 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 the crater lake.[2] The eruption occurred in March and 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.[1] The volume of lava erupted was 9x105 m3 and the volume of tephra expelled was 2.6x107 m3.[3]

The Quaternary age Gas Rocks dacite domes some three km to the northeast were the site of a phreatic eruption some 2300 years ago.[1]

Map showing volcanoes of Alaska.

References

Ukinrek eruption 1977