Crater lake

From World travel guide

This page describes the geological feature. For the lake of the same name in Oregon, see Crater Lake.

A crater lake is a lake that forms in a volcanic crater, caldera, or maar. Incoming precipitation fills the depression to form a deepening lake, until an equilibrium is reached between the rate of water coming in and the rate of water loss due to evaporation, subsurface drainage, and possibly also surface outflow if the lake fills the crater up to the lowest point on its rim. Crater lakes covering active (fumarolic) volcanic vents are often known as volcanic lakes, and the water within them is typically acidic, saturated with volcanic gases, and cloudy with a strong greenish color. Lakes located in dormant or extinct volcanoes tend to have fresh water, and the water clarity in such lakes is often exceptional due to the lack of inflowing streams and sediment.

A well-known crater lake, which bears the same name as the geological feature, is Crater Lake in Oregon, USA. It is located in the caldera of Mount Mazama, hence the name "Crater Lake" is somewhat of a misnomer. It is the deepest lake in the United States with a depth of Template:Convert. Crater Lake is fed solely by falling rain and snow, with no inflow or outflow at the surface, and hence has the clearest water of any lake in the world.

The highest volcano in the world, Template:Convert Ojos del Salado, has a permanent crater lake about Template:Convert in diameter at an elevation of Template:Convert on its eastern side.<ref>Andes Website - Information about Ojos del Salado volcano, a high mountain in South America and the World's highest volcano</ref> This is most likely the highest lake of any kind in the world.

Due to their unstable environment, some crater lakes exist only intermittently. Caldera lakes in contrast can be quite large and long-lasting; for instance, Lake Toba formed after its eruption around 70,000 years ago and has an area of over 1,000 square kilometres.

While many crater lakes are picturesque, they can also be deadly. Gas discharges from Lake Nyos suffocated 1,800 people in 1986, and crater lakes such as Mount Ruapehu's often contribute to destructive lahars.

Lakes can also fill impact craters, but these are not usually referred to as crater lakes except in a few isolated cases. Example of such impact crater lakes include Manicouagan in Quebec, Lake Bosumtwi in Ghana and Siljan in Sweden.

1 Notable crater lakes
2 See also
3 References
4 External links

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Notable crater lakes

Lake	Location
Lake of Albano	Template:ITA
Lago de Atitlán	Template:GUA
Blue Lake	Template:AUS, South Australia
Lake Bolsena	Template:ITA
Lake Bracciano	Template:ITA
Laguna Chicabal	Template:GUA
Lago de Coatepeque	Template:SLV
Crater Lake	Template:USA, Oregon
Cuicocha	Template:ECU
Heaven Lake (Chonji / Tianchi)	Template:PRK / Template:CHN
Volcán Irazú	Template:CRC
Kapoho Crater	Template:USA, Hawaii
Mount Katmai	Template:USA, Alaska
Rano Kau	Template:CHI, Rapa Nui (Easter Island)
Kelut	Template:IDN
Kerið	Template:ISL
Kurile Lake	Template:RUS (Kamchatka)
Medicine Lake Volcano	Template:USA, California
Lake Manicouagan	Template:CAN
Mashu	Template:JPN
Lake Nemi	Template:ITA
Nemrut	Template:TUR
Newberry Volcano	Template:USA, Oregon
Lake Nyos	Template:CMR
Mount Pinatubo	Template:PHI
Rano Raraku	Template:CHI, Rapa Nui (Easter Island)
Mount Ruapehu	Template:NZL
Lake Shikotsu	Template:JPN
Soufrière	Template:Flagicon St. Vincent
Taal Lake	Template:PHI
Lake Taupo	Template:NZL
Tazawa	Template:JPN
Lake Toba	Template:IDN
Towada	Template:JPN
Lake Vico	Template:ITA
Nazko Cone	Template:CAN
Lake Wenchi <ref>http://www.gtz.de/de/praxis/11695.htm Description of Mount Wenchi crater lake on the website of GTZ</ref>	Template:ETH