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How did the eruption of Mount Mazama create Crater Lake?
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Pacific mountain system
Coast Mountains along the Torres Channel, an arm of Atlin Lake, northwestern British Columbia, Canada.
Crater Lake was formed approximately 7,700 years ago following a cataclysmic eruption of Mount Mazama, a prehistoric volcano in the Cascade Range of Oregon.123
During this violent event, massive amounts of magma were ejected from the mountain. As the underlying magma chamber emptied, the structural support for the volcano's summit was lost, causing the top of the volcanic cone to collapse inward. This collapse created a large, bowl-shaped volcanic depression known as a caldera. Over time, this depression filled with water, primarily from precipitation, resulting in the formation of Crater Lake. Subsequent minor volcanic activity within the caldera created features such as Wizard Island, which rises from the lake floor.421