No latest activity reported for Ukinrek Maars.

Below is a summary of eruption dates and Volcanic Explosivity Indices (VEI).

The following references are the sources used for data regarding this volcano. References are linked directly to our volcano data file. Discussion of another volcano or eruption (sometimes far from the one that is the subject of the manuscript) may produce a citation that is not at all apparent from the title. Additional discussion of data sources can be found under Volcano Data Criteria.

Fierstein J, 2007. Explosive eruptive record in the Katmai region, Alaska Peninsula: an overview. {Bull Volc}, 69: 469-509

Hildreth W, Fierstein J, Calvert A T, 2007. Blue Mountain and the Gas Rocks: rear-arc dome clusters on the Alaska Peninsula. {In}: Haeussler P J, Galloway J P (eds), Studies by the U.S. Geological Survey, {U S Geol Surv Prof Pap}, 1739-A: 1-27

Kienle J, Kyle P R, Self S, Motyka R J, Lorenz V, 1980. Ukinrek Maars, Alaska, I. April 1977 eruption sequence, petrology and tectonic setting. {J Volc Geotherm Res}, 7: 11-37

Miller T P, McGimsey R G, Richter D H, Riehle J R, Nye C J, Yount M E, Dumoulin J A, 1998. Catalogue of the historically active volcanoes of Alaska. {U S Geol Surv Open-File Rpt}, 98-582: 1-104

Motyka R J, Liss S A, Nye C J, Moorman M A, 1993. Geothermal resources of the Aleutian arc. {Alaska Div Geol Geophys Surv, Prof Rpt}, no 114, 17 p and 4 map sheets

Wood C A, Kienle J (eds), 1990. {Volcanoes of North America}. Cambridge, England: Cambridge Univ Press, 354 p

Ukinrek Maars are two explosion craters that were created in an area without previous volcanic activity during a 10-day-long phreatomagmatic eruption March-April 1977. The basaltic maars were erupted through glacial deposits in the Bering Sea lowlands 1.5 km south of Becharof Lake and 12 km west of Peulik volcano; their location is related to the regional Bruin Bay fault. The elliptical West Maar, which was the first to form, is 105 x 170 m wide and 35 m deep. The other maar, 600 m to the east, is 300 m wide and 70 m deep. Both maars are now filled by crater lakes; the eastern lake encircles a 49-m-high lava dome that was emplaced at the end of the eruption. Base surges were directed primarily to the NW. Juvenile material from the Ukinrek eruptions was of mantle-derived olivine basaltic composition. The dacitic Gas Rocks lava domes, of Quaternary age, are located on the shores of Becharof Lake, 3 km north of Ukinrek maars and were the site of a phreatic eruption about 2300 years ago.