Did You Know: Crater Lake National Park

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This segment introduces the fact that the deepest lake in the U.S. is above a dormant volcano. It explains the history of its construction, which is also illustrated with topography and bathymetry map, and its current composition. 

Produced by the Space Telescope Science Institute’s Office of Public Outreach in collaboration with the NASA Earth Observatory (https://earthobservatory.nasa.gov/).
Story adapted from Image of the Day post by Andi Hollier, Hx5, JETS Contract at NASA-JSC: https://earthobservatory.nasa.gov/images/90647/crater-lake

  • Photo of Crater Lake, Oregon (Expedition 52 crew, International Space Station)
  • Topography and bathymetry map based on LiDAR survey and multi-beam sonar survey (U.S. Geological Service)
  • Photo of Crater Lake in the summer (National Park Service)
  • Photo of Crater Lake in the summer, showing Wizard Island (National Park Service)
  • Written by Claire Blome
  • Designed by Dani Player
  • Music courtesy of Associated Production Music LLC

Text, Did You Know? Crater Lake, Oregon.
The deepest lake in the U.S. is above a dormant volcano. A satellite image of large circular lake in a crater surrounded by a snowy ridge and puffy white clouds. Crater Lake, National Park. Photographed by Expedition 52 Crew, International Space Station. Thousands of years ago, Mount Mazama, a volcano in southern Oregon, erupted catastrophically. It ejected volcanic ash that settled as far as Alberta, Canada, more than 1,700 kilometers, or 1,050 miles away. As its magma reservoir nearly emptied, the peak collapsed, forming a caldera, a large volcanic depression. Now filled with water, the caldera is known as Crater Lake. It is more than 580 meters, or 1,900 feet, deep. A topography and bathymetry map based on LIDAR survey and multi-beam sonar survey, by the U.S. Geological Service, shows the rim of the caldera clearly with several dome like islands inside. Researchers have been able to untangle the volcano's history by studying the geological evidence, layers of pumice and ash, and the topography of the bottom of the lake and the region in general. Carbon dating of charred trees revealed that the eruption happened around 7,000 years ago. Over centuries, rain and snow filled the basin. Minor eruptions continued inside the newly formed caldera in the centuries that followed, building Wizard Island and Merriam Cone. The two inclusions are labelled on the image.
A view of the lake from along the ridge of the caldera, photographed by the National Park Service. Today, Crater Lake's water levels are relatively stable. No rivers or streams flow in or out, and snow typically blankets the surrounding slopes through June. Evaporation and seepage are the lake's only routes of water loss.
A cone shaped hill marks the center of an island in the middle of the lake under a sunny sky, with puffy white clouds on the horizon. Although the water in Crater Lake often appears to be a deep shade of blue, it is actually colorless. Its deep waters remain free of suspended sediment. The color seen in this image is caused in part by a reflection of the sky, clouds, and crater walls.
Crater Lake lies along a chain of active, dormant, and extinct volcanoes that extends from California to British Columbia.
Although another eruption at Crater Lake is unlikely, the area is still monitored for volcanic activity.