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There are no activity reports for Seguam.
Summary of eruption dates and Volcanic Explosivity Indices (VEI).
|Start Date||Stop Date||Eruption Certainty||VEI||Evidence||Activity Area or Unit|
|1993 May 28||1993 Aug 31 (in or after)||Confirmed||2||Historical Observations||Near Pyre Peak|
|1992 Dec 27||1992 Dec 30||Confirmed||2||Historical Observations||Pyre Peak (1.5 km south of summit)|
|1977 Mar 6||1977 Mar 8 (?)||Confirmed||1||Historical Observations||Pyre Peak (2.5 km SE of summit)|
|[ 1927 ]||[ Unknown ]||Uncertain|
|1892 Apr 15 ± 45 days||Unknown||Confirmed||3||Historical Observations|
|1891 Dec||Unknown||Confirmed||2||Historical Observations|
|[ 1827 ]||[ Unknown ]||Uncertain|
|0250 ± 500 years||Unknown||Confirmed||Uranium-series||West of Wilcox volcano|
|4050 BCE ± 1000 years||Unknown||Confirmed||0||Uranium-series||W flank of cone in eastern caldera|
|5100 BCE ± 1000 years||Unknown||Confirmed||0||Uranium-series||W flank of cone in eastern caldera|
|7300 BCE ± 1000 years||Unknown||Confirmed||5||Ar/Ar||Wilcox volcano|
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.
Coats R R, 1950. Volcanic activity in the Aleutian Arc. U S Geol Surv Bull, 974-B: 35-47.
Henning R A, Rosenthal C H, Olds B, Reading E (eds), 1976. Alaska's volcanoes, northern link in the ring of fire. Alaska Geog, 4: 1-88.
IAVCEI, 1973-80. Post-Miocene Volcanoes of the World. IAVCEI Data Sheets, Rome: Internatl Assoc Volc Chemistry Earth's Interior..
Jicha B R, Singer B S, 2006. Volcanic history and magmatic evolution of Seguam Island, Aleutian Island arc, Alaska. Geol Soc Amer Bull, 118: 805-822.
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.
Myers J D, 1994. The Geology, Geochemistry and Petrology of the recent Magmatic Phase of the Central and Western Aleutian Arc. Unpublished manuscript, unpaginated.
Singer B S, Myers J D, Frost C D, 1992. Mid-Pleistocene lavas from the Seguam volcanic center, central Aleutian arc: closed-system fractional crystallization of a basalt to rhyodacite eruptive suite. Contr Mineral Petr, 110: 87-112.
Smith R L, Shaw H R, Luedke R G, Russell S L, 1978. Comprehensive tables giving physical data and thermal energy estimates for young igneous systems of the United States. U S Geol Surv Open-File Rpt, 78-925: 1-25.
Smithsonian Institution-SEAN, 1975-89. [Monthly event reports]. Bull Scientific Event Alert Network (SEAN), v 1-14.
Wood C A, Kienle J (eds), 1990. Volcanoes of North America. Cambridge, England: Cambridge Univ Press, 354 p.
The elliptical, 11.5 x 24 km island of Seguam, lying between Amlia and Amukta Islands in the central Aleutians, contains two calderas with Holocene post-caldera cones. Growth of the basaltic-to-rhyolitic Wilcox volcano on the east side of the island during the late Pleistocene was followed by edifice collapse and an associated ignimbrite eruption about 9000 years ago, leaving a horseshoe-shaped caldera open to the west, inside which a rhyolitic cone was constructed. The 3 x 4 km wide westernmost caldera has a central scoria cone, Pyre Peak, which rises above the caldera rim and is the source of most of the historical eruptions of Seguam volcano. A very young basaltic field surrounds Pyre Peak, and lava flows partially fill the caldera and reach the southern coast. Older Holocene lava flows were erupted from vents within the eastern caldera, and a monogenetic Holocene cone forms Moundhill volcano on the eastern tip of the island.