Mount Redoubt rises to 3108 m on the west side of Cook Inlet, 170 km SW of Anchorage. Redoubt volcano was constructed over a basement of glacially eroded Mesozoic granitic rocks, seen here in the foreground. The volcano has been very active during the Holocene, producing at least 30 tephra layers in the Cook Inlet basin stratigraphy. A steam plume rises from the summit crater, which is breached to the north, in this view from the NE following its 1989-90 eruption. Iliamna volcano is visible in the left distance. Photo by Christina Neal (U.S. Geological Survey, Alaska Volcano Observatory).