Ugashik, Alaska, USA
U.S. Geological Survey photo by Bruce Yount (fair use policy)
Ugashik is the ring of ridges—the caldera—around the five domes of Peulik volcano, on the Alaska Peninsula. A caldera is the low rim left behind when a large volcano collapses in upon itself after a series of large eruptions. Usually a new volcano starts to grow inside, eventually covering it. Ugashik is a typical caldera, less well-formed than the Crater Lake caldera.
