Crater lake


Crater lake
Landsat image of Lake Toba, the largest volcanic crater lake in the world.
Satellite imagery of Manicouagan Reservoir / Manicouagan impact crater, the largest impact crater lake in the world.
Heaven Lake (Chonji / Tianchi), North Korea / China
Crater Lake in Oregon, USA
Cuicocha, Ecuador
Lake formed after 1991 eruption of Mount Pinatubo, Philippines

A crater lake is a lake that forms in a volcanic crater or caldera, such as a maar; less commonly and with lower association to the term a lake may form in an impact crater caused by a meteorite. Sometimes lakes which form inside calderas are called caldera lakes, but often this distinction is not made. Crater lakes covering active (fumarolic) volcanic vents are sometimes known as volcanic lakes, and the water within them is often 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 can be exceptional due to the lack of inflowing streams and sediment.

Contents

Formation

Crater lakes form as precipitation within the rim fills the created depression. The water level rises until an equilibrium is reached between the rate of incoming and outgoing water. Sources of water loss singly or together, may include evaporation, subsurface seepage, and in places, surface leakage or overflow when the lake level reaches the lowest point on its rim. At such a saddle location, the upper portion of the lake is contained only by its adjacent natural volcanic dam; continued leakage through or surface outflow across the dam can erode its included material, thus lowering lake level until a new equilibrium of water flow, erosion and rock resistance is established. If the volcanic dam portion erodes rapidly or fails catastrophically, the occurrence produces a breakout or outburst flood. With changes in environmental conditions over time, the occurrence of such floods is common to all natural dam types.

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 something of a misnomer. It is the deepest lake in the United States with a depth of 594 m (1,949 ft). Crater Lake is fed solely by falling rain and snow, with no inflow or outflow at the surface, and hence is one of the clearest lakes in the world.[1]

The highest volcano in the world, 6,893 metres (22,615 ft) Ojos del Salado, has a permanent crater lake about 100 metres (300 ft) in diameter at an elevation of 6,390 m (20,960 ft) on its eastern side.[2] 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 Canada, Lake Bosumtwi in Ghana and Siljan in Sweden.

List of volcanic crater lakes

Lake Location
Africa
Lake Nyos Cameroon
Lake Wenchi [3] Ethiopia
Asia
Ijen Indonesia
Lake Toba Indonesia
Kawah Putih Indonesia
Segara Anak Indonesia
Kelut Indonesia
Yak Loum Cambodia
White Deer Lake (Baengnokdam) South Korea
Heaven Lake (Chonji / Tianchi) North Korea / China
Lake Shikotsu Japan
Towada Japan
Mashu Japan
Tazawa Japan
Lake Pinatubo Philippines
Taal Lake Philippines
Kurile Lake Russia (Kamchatka)
Nemrut Turkey
Europe
Lagoa das Sete Cidades Azores
Laacher See Eifel
Eyjafjallajökull (volcano) Iceland
Kerið Iceland
Lake of Albano Italy
Lake Nemi Italy
Lake Avernus Italy
Lake Bolsena Italy
Lake Vico Italy
Lake Bracciano Italy
Lagoa do Fogo Portugal
Lake Sfânta Ana Romania
Australasia
Mount Ruapehu New Zealand
Lake Taupo New Zealand
Lake Rotorua New Zealand
Lake Wisdom Papua New Guinea
Blue Lake South Australia
North America
Nazko Cone Canada
Lago Los Espinos Mexico
Mount Katmai USA Alaska
Medicine Lake Volcano USA California
Green Lake,[4] Kapoho Crater, Kīlauea USA Hawaii
Crater Lake USA Oregon
Newberry Volcano USA Oregon
Yellowstone Lake USA Wyoming
Central America
Volcán Irazú Costa Rica
Volcán Maderas Nicaragua
Lago de Coatepeque (Coatepeque Lake) El Salvador
Laguna Verde (Apaneca, Sonsonate) El Salvador
Lago De Ilopango (Ilopango Lake) El Salvador
Lago de Amatitlán Guatemala
Lake Ipala Guatemala
Lago de Atitlán Guatemala
Laguna de Ayarza Guatemala
Laguna de Calderas (Pacaya) Guatemala
Laguna Chicabal Guatemala
Soufrière Saint Vincent
South America
Laguna del Maule Chile
Rano Kau Chile - Easter Island
Rano Raraku Chile - Easter Island
Cuicocha Ecuador
Quilotoa Ecuador

List of meteor crater lakes

Lake Location
Africa
Lake Bosumtwi Ghana
Asia
Lonar crater lake India
Europe
Lake Kaali Estonia
Lake Siljan Sweden
Dellen Sweden
North America
Lake Manicouagan Canada
West Hawk Lake Canada

References

Further reading

External links


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