Book 30, Question 7
How does a volcano make a lake?
Rain and snow filled the bowl over hundreds of years.
Crater Lake in Oregon formed about 7,700 years ago when a volcano erupted and its top collapsed, leaving a huge bowl called a caldera. No rivers flow in or out, so it is incredibly clear and deep. It is the deepest lake in the United States, at nearly 2,000 feet.
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Quick answers
How does a volcano make a lake?
Crater lakes usually form through the accumulation of rain, snow and ice melt, and groundwater in volcanic craters.
Source: National Park Service
More fun facts
- The basin that now contains Crater Lake is the resulting collapse caldera, 1,200 meters deep and 8 to10 kilometers in diameter at the rim.
- On the other hand, Mount Katmai’s crater lake is quite young as the caldera formed in 1912 during the Valley of Ten Thousand Smokes eruption.
- Wizard Island, one of the two major caldera-floor volcanic cones, erupted additional material into the lake as it finished filling.
- Several post-caldera volcanic features are present at Crater Lake, although only Wizard Island breaks the lake surface.
- Calderas filled with water can produce tremendous flooding in the immediate vicinity if the caldera wall fails, as happened to Aniakchak Crater in Alaska when its rim was breached.
Sources: U.S. Geological Survey, National Park Service
Questions kids ask
How old is the crater that holds Crater Lake?
Nine separate dome complexes once made up the area in and around the lake until a large explosive eruption formed the crater about 5,800 years ago.
Source: National Park Service