Global Volcanism Program | Image GVP-05269
Augustine forms an 8 x 12 km island in Kamishak Bay, in the southern Cook Inlet. The cone is a complex of overlapping summit lava domes. An apron of pyroclastic debris, consisting mostly of large debris avalanche deposits produced by collapse of portions of the summit lava domes, extends to the sea on all sides. West Island, at front left in this 1989 view from the west, is the product of a debris avalanche roughly 250-450 years ago.
Photo by Tom Miller, 1989 (Alaska Volcano Observatory, U.S. Geological Survey).