Global Volcanism Program | Image GVP-05339
Aniakchak is a 10-km-wide summit caldera containing numerous cones, lava domes, and lava flows on the caldera floor. The largest intra-caldera cone is Vent Mountain that reaches 430 m in height and has a diameter at the base of 2.5 km. At least 20 Holocene eruptions may have occurred before the Aniakchak II caldera-forming eruption.
Photo by M. Woodbridge Williams (National Park Service).