Great Sitkin, a stratovolcano, is built in a caldera at the summit of a shield volcano. Great Sitkin is suspected of erupting in 1760. Since then, it may have erupted as many as 12 times. The last know eruption was in 1974 when an explosive eruption (VEI=2) produced lava flows and a dome. An eruption was suspected in 1987 but not confirmed. Photo by R.E. Wilcox, U.S. Geological Survey, July 8, 1952.

The crater and 1945 crater dome of Great Sitkin. Plate 6 of U.S. Geological Bulletin 1028-B.


Sources of Information:

Simkin, T., and Siebert, L., 1994, Volcanoes of the World: Geoscience Press, Tucson, Arizona, 349 p.

Simons, F.S., and Mathewson, D.E., 1955, Geology of Great Sitkin Island, Alaska: U.S. Geological Bulletin 1028-B, p. 21-43.

Neuweld, M.A., 1987, The petrology and geochemistry of the Great Sitkin suite: Implications for the genesis of calc-alkaline magmas: M.S. thesis, Cornell University, Ithaca, NY, 174 p.

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United States