Wizard Island in the western part of Crater Lake, Oregon. The island consists of a cinder cone and lava flows erupted soon after the caldera formed about 7,700 years ago and rises 820 m above the deepest part of the caldera floor and 233 m above water level. The lake covers several other lava flows and a dome erupted from vents on the caldera floor. The most recent eruption of Crater Lake occurred about 5,000 years ago.

The prominent great cliff in upper left is a thick lava flow known as Llao Rock. It is one of four lava flows (rhyodacite composition) that were erupted from vents north of the summit of Mount Mazama only a few centuries before its climatic caldera-forming event. This giant eruption expelled about 50 km³ of magma. By comparison, the 1980 eruption of Mount St. Helens, Washington, ejected less than 0.5 km³ of magma and the 1912 eruption of Novarupta, Katmai National Park, Alaska, ejected about 15 km³ of magma.