Iliamna is a stratovolcano just west of Cook Inlet. Eruptions are suspected (but not confirmed) in 1768, 1786, 1793, 1843, 1933, 1947, and 1952. Iliamna did erupt in 1778, 1867, 1876, and, most recently, 1953. Steam plumes were observed in 1978 and 1987. Photograph of steam and volcanic gas released by active fumaroles on north face of Iliamna by R. McGimsey, U.S. Geological Survey, May 6, 1986. USGS Digitial Data Series 96-040, Neal and McGimsey.
Iliamna is made of andesite lava flows and tephra. The volcano is not a symmetric cone but is made of summit peak and four other peaks that make a 5-km-long ridge. Glaciers cover most of the volcano.
Find more information about Iliamna at the Alaska Volcano Observatory