Global Volcanism Program | Image GVP-05335
The 4.5-km-wide Ugashik caldera formed during the late Pleistocene. Five unglaciated Holocene lava domes occupy the caldera, seen here from the east with Upper Ugashik Lake in the background. Peulik has a summit crater that opens to the west and contains a lava dome.
Photo by Betsy Yount (Alaska Volcano Observatory, U.S. Geological Survey).