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Volcanic Landforms

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Crater Lake

Crater Lake


Credit: Stuart Seeger
Source: http://en.wikipedia.org/wiki/File:Wizard_Island_in_Crater_Lake_National_Park_-_Oregon_2008.jpg
License: CC BY-NC 3.0

Crater Lake is a beautiful blue jewel in the Cascade Mountains of Oregon. The eruption of Mount St. Helens in 1980 was the closest thing in recent history to the enormous eruption that created this lake basin.

Why It Matters

  • Crater Lake is not in a crater, but a caldera.
  • The mountain that exploded to create Crater Lake is called Mount Mazama. The eruption was approximately 7,700 years ago.
  • Like the other volcanoes of the Cascade Range, Mazama was a composite volcano (stratovolcano).
  • Wizard Island is a cinder cone within the lake. Its last eruption was about 6,600 years ago.
    Source: http://en.wikipedia.org/wiki/File:Mount_Mazama_eruption_timeline.PNG
    License: CC BY-NC 3.0

    Caldera formation shown through the eruption timeline of Mount Mazama [Figure2]


Explore More

With the links below, learn more about Crater Lake. Then answer the following questions.

  1. What is the difference between a crater and a caldera? Which feature is Crater Lake?
  2. How was the eruption that created Wizard Island different from the one that created Crater Lake?
  3. Why did the summit of the mountain collapse?
  4. What is the source of water in the lake?
  5. Why is the lake so clear and blue?

Image Attributions

  1. [1]^ Credit: Stuart Seeger; Source: http://en.wikipedia.org/wiki/File:Wizard_Island_in_Crater_Lake_National_Park_-_Oregon_2008.jpg; License: CC BY-NC 3.0
  2. [2]^ Credit: U.S. GEOLOGICAL SURVEY and the NATIONAL PARK SERVICE; Source: http://en.wikipedia.org/wiki/File:Mount_Mazama_eruption_timeline.PNG; License: CC BY-NC 3.0

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