Crater Lake (Klamath language: Giiwas) is a volcanic crater lake in south-central Oregon in the Western United States. It is the main feature of Crater Lake National Park and is a tourist attraction for its deep blue color and water clarity. The lake partly fills a caldera that was formed around 7,700 (± 150) years ago
by the collapse of the volcano Mount Mazama. No rivers flow into or out of the lake; the evaporation is compensated for by rain and snowfall at a rate such that the total amount of water is replaced every 150 years. With a depth of , the lake is the deepest in the United States. In the world, it ranks eleventh for maximum depth, as well as fifth for mean depth.
Crater Lake features two small islands. Wizard Island, located near the western shore of the lake, is a cinder cone about in size. Phantom Ship, a natural rock pillar, is located near the southern shore.
Since 2002, one of Oregon's regular-issue license-plate design has featured Crater Lake and a one-time plate surcharge is used to support the operation of Crater Lake National Park. The commemorative Oregon State Quarters, which was released by the United States Mint in 2005, features an image of Crater Lake on its reverse.
The lake and surrounding park areas offer many recreational activities, including hiking, biking, snowshoeing, fishing, and cross-country skiing, and during the summer, campgrounds and lodges at Crater Lake are open to visitors.
A Native American connection with this area has been traced back to before the eruption of Mount Mazama. Archaeologists have found sandals and other artifacts buried under layers of ash, dust, and pumice that antedate the eruption roughly 7,700 years ago. Crater Lake remains significant to the Klamath tribes today. The Klamath name for the lake is Giiwas.
In June 1853, Isaac Skeeter, John Wesley Hillman, and another man were the first non-Native Americans to report sighting the lake, while on a mining trip; Skeeter named it "Deep Blue Lake," inspired by Hillman's description of the site. The lake was renamed at least three times, as Blue Lake, Lake Majesty, and finally Crater Lake.
When considering the mean, or average depth of lakes, Crater Lake becomes the deepest lake in the Western Hemisphere and the third-deepest in the world. Crater Lake Institute Director and Limnology Owen Hoffman states that "Crater Lake is the deepest, when compared on the basis of average depth among lakes whose basins are entirely above sea level. The average depths of Lakes Lake Baikal and Lake Tanganyika are deeper than Crater Lake; however, both have basins that extend below sea level."
Lava eruptions later created a central platform, Wizard Island, Merriam Cone, and other, smaller volcanic features, including a rhyodacite dome that was eventually created atop the central platform. Sediments and landslide debris also covered the caldera floor.
Eventually, the caldera cooled, allowing rain and snow to accumulate and form a lake. Landslides from the caldera rim thereafter formed debris fans and turbidite sediments on the lake bed. and remained common and active during this period. Also after some time, the slopes of the lake's caldera rim more or less stabilized, streams restored a radial drainage pattern on the mountain, and dense forests began to revegetate the barren landscape. It is estimated that about 720 years was required to fill the lake to its present depth of . Much of this occurred during a period when the prevailing climate was less moist than at present.
Some hydrothermal activity remains along the lake floor, suggesting that at some time in the future, Mazama may erupt once again.
Crater Lake is also known for the "Old Man of the Lake", a full-sized tree which is now a log that has been bobbing vertically in the lake for over a century. The low temperature of the water has slowed the decomposition of the wood, hence its longevity.
In 1987, scientists sent a submersible down to the depths of Crater Lake to obtain more information about the geology at the bottom of the lake, and inspect moss samples found in moss beds as deep as .
Due to several unique factors, mainly that the lake has no inlets or tributaries, the waters of Crater Lake are some of the purest in the world because of the absence of pollutants. Clarity readings from a Secchi disk have consistently been measured as being , which is very clear for any natural body of water. In 1997, scientists recorded a record clarity of .
The lake has relatively high levels of dissolved salts, total alkalinity, and conductivity. The average pH has generally ranged between 7 and 8.
Swimming is permitted in Crater Lake, but the only legal and safe way to get to the shore is by following Cleetwood Cove trail and people can enter the water from there. Other activities include fishing and a 2-hour boat tour around the lake provided by a Park Ranger from Crater Lake National Park.
As the region lies within a national park area, collecting rocks within the vicinity is prohibited unless a permit is obtained. The park's facilities lie at Rim Village, at the southern edge of the caldera. Lodging and camping facilities open during the summer season between May and October. No lodges, gas stations, or camping areas remain open from October through late May. Popular activities within Crater Lake National Park include cycling, fishing, cross-country skiing, and snowshoe running.
Geology
Climate
Ecology
Sacred significance
Recreation
See also
Notes
External links
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