Upper image: Panoramic photograph taken from visitor overlook on The Watchman by Peter Dartnell. View is to the east. Digital photographic processing by Eleanore Ramsey.
Lower image: Digital perspective view of generalized geologic map of the lake floor draped over shaded-relief image of 2-m bathymetry. Illuminated from 225 degree azimuth and 45 degree elevation. Created with ArcInfo and USGS perspective view calculation program. Scale varies with distance.
people each year visit Crater Lake National Park in the Cascade Range
of southern Oregon. Volcanic peaks, evergreen forests, and Crater Lakes
incredibly blue water are the parks main attractions. Crater Lake
partially fills the caldera that formed approximately 7,700 years ago
by the eruption and subsequent collapse of a 12,000-foot volcano called
Mount Mazama. The caldera-forming or climactic eruption of Mount Mazama
drastically changed the landscape all around the volcano and spread a
blanket of volcanic ash at least as far away as southern Canada.
the climactic event, Mount Mazama had a 400,000 year history of cone building
activity like that of other Cascade volcanoes such as Mount Shasta. Since
the climactic eruption, there have been several less violent, smaller
postcaldera eruptions within the caldera itself. However, relatively little
was known about the specifics of these eruptions because their products
were obscured beneath Crater Lakes surface. As the Crater Lake region
is still potentially volcanically active, understanding past eruptive
events is important to understanding future eruptions, which could threaten
facilities and people at Crater Lake National Park and the major transportation
corridor east of the Cascades.
Recently, the lake bottom was mapped with a high-resolution multibeam echo sounder. The new bathymetric survey provides a 2m/pixel view of the lake floor from its deepest basins virtually to the shoreline. Using Geographic Information Systems (GIS) applications, the bathymetry data can be visualized and analyzed to shed light on the geology, geomorphology, and geologic history of Crater Lake.
Download this map as a PDF file (6.7 MB)
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Other links of interest:
Bathymetry and selected perspective views of Crater Lake, OR (USGS Water Resources Investigations Report 01-4046)
2000 multibeam sonar survey
of Crater Lake, OregonData, GIS, images, and movies (USGS
Digital Data Series DDS-72)
Mount Mazama and Crater LakeGrowth and destruction of a Cascade volcano (USGS Fact Sheet 92-02)
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| Department of the Interior | U.S. Geological Survey | Geologic Division | Volcano Hazards Program |