Wizard Island

What is Wizard Island?

Wizard Island formed due to the processes that happened after the catastrophic eruption of Mount Mazama. This page covers the time before, during, and after the eruption of Mount Mazama and how it contributed to forming Wizard Island.

Eruption of Mt. Mazama

Times Before the Eruption

Before Crater Lake and Wizard Island was Mount Mazama, a towering Volcano at approximately 12,000 ft in height, it was part of the Cascade Range in Southwestern Oregon extending north. Before its inevitable collapse 7,700 years ago, it was almost half a million years old.

After the Eruption

After Mount Mazama erupted and collapsed the roof of the magma chamber, sinking to 8,157 feet (from 12,000), it gave Earth's magma a catalyst to funnel upward and begin forming small islands in the new, giant basin created from the explosion. Then, as time went on, magma eventually started to flow to the surface of the basin, forming new mounds of igneous rock. The mounds were called the Merriam Cone (Northeast), Rhyodacite Dome (West), Central Platform, and Wizard Island (West). At the same time, however, rain and snowfall were also piling up, increasing the water level at about the same rate the magma was depositing.

Topographic map of Crater Lake, Oregon

Wizard Island Today

Mount Mazama may have collapsed 7,700 years ago, but the last activity in Crater Lake was only 4,800 years ago around in the east. The continuous rain/snowfall filled up the basin but eventually stopped 750 years after the initial eruption due to a very porous layer in the walls of the crater. With that, it covered up every other formation in the basin except for Wizard Island, by which only 2% of it was showing. Now, that's the only land we can see in Crater Lake and it gets its name because it resembles a Wizard's hat.

Wizard Island, U.S Fish and Wildlife Service

U.S. Department of the Interior. (2022a, November 2). Wizard Island and other post-caldera eruptions. National Parks Service. https://www.nps.gov/crla/learn/nature/wizardisland.htm

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