A volcanic crater lake is a

lake A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much large ...

in a

crater Crater may refer to: Landforms * Impact crater, a depression caused by two celestial bodies impacting each other, such as a meteorite hitting a planet * Explosion crater, a hole formed in the ground produced by an explosion near or below the surf ...

that was formed by explosive activity or a

collapse Collapse or its variants may refer to: Concepts * Collapse (structural) * Collapse (topology), a mathematical concept * Collapsing manifold * Collapse, the action of collapsing or telescoping objects * Collapsing user interface elements ** ...

during a

volcanic eruption Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are oft ...

Formation

Lakes in

caldera A caldera ( ) is a large cauldron-like hollow that forms shortly after the emptying of a magma chamber in a volcano eruption. When large volumes of magma are erupted over a short time, structural support for the rock above the magma chamber is ...

s fill large craters formed by the collapse of a volcano during an eruption. Lakes in

maar A maar is a broad, low-relief volcanic crater caused by a phreatomagmatic eruption (an explosion which occurs when groundwater comes into contact with hot lava or magma). A maar characteristically fills with water to form a relatively shallo ...

s fill medium-sized craters where an eruption deposited debris around a vent. Crater lakes form as the created depression, within the crater rim, is filled by water. The water may come from

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

groundwater Groundwater is the water present beneath Earth's surface in rock and Pore space in soil, soil pore spaces and in the fractures of stratum, rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit ...

circulation (often hydrothermal fluids in the case of volcanic craters) or melted ice. Its level rises until an equilibrium is reached between the rates of incoming and outgoing water. Sources of water loss singly or together may include

evaporation Evaporation is a type of vaporization that occurs on the surface of a liquid as it changes into the gas phase. High concentration of the evaporating substance in the surrounding gas significantly slows down evaporation, such as when h ...

, 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.

Examples

A well-known crater lake, which bears the same name as the geological feature, is Crater Lake in

Oregon Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...

. It is located in the caldera of Mount Mazama. It is the deepest lake in the United States with a depth of . 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. The highest

volcano A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface. On Earth, volcanoes are most often found where tectonic plates ...

in the world, 6,893-m (22,615-ft) Ojos del Salado in

Chile Chile, officially the Republic of Chile, is a country in the western part of South America. It is the southernmost country in the world, and the closest to Antarctica, occupying a long and narrow strip of land between the Andes to the eas ...

, has a permanent crater lake about in diameter at an elevation of on its eastern side. This is most likely the highest lake of any kind in the world. Due to their unstable environments, some crater lakes exist only intermittently. Caldera lakes in contrast can be quite large and long-lasting. For instance, Lake Toba (

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania between the Indian and Pacific oceans. It consists of over 17,000 islands, including Sumatra, Java, Sulawesi, and parts of Borneo and New Gui ...

) formed after its eruption around 75,000 years ago. At around by in extent and deep at its deepest point, Lake Toba is the largest crater lake in the world.

Dangers

While many crater lakes are picturesque, they can also be deadly. Gas discharges from Lake Nyos in (

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the ...

) suffocated 1,800 people in 1986, and crater lakes such as Mount Ruapehu's (New Zealand) often contribute to destructive

lahar A lahar (, from jv, ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water. The material flows down from a volcano, typically along a river valley. Lahars are extr ...

Distinction from other volcanic lakes

Certain bodies of water, although their formation is directly related to volcanic activity, are not usually referred to as crater lakes, including: *Lakes created by volcanic dams due to lava flowing outside of the volcanic edifice/

(such as Garibaldi Lake in Canada, Fuji Five Lakes in Japan) *Closed

atoll An atoll () is a ring-shaped island, including a coral rim that encircles a lagoon partially or completely. There may be coral islands or cays on the rim. Atolls are located in warm tropical or subtropical oceans and seas where corals can gro ...

lagoons (such as Clipperton lagoon), whose formation process also implies subsequent biogeomorphologic processes *Ponds encountered at the bottom of waterfalls occurring in volcanic canyons in a volcanic context, but not within a volcanic edifice/caldera (such as

Trou de Fer The Trou de Fer ("Iron Hole") is a canyon on Reunion Island, off the coast of Madagascar in the Indian Ocean. The primary river flowing through the gorge, which is up to deep, is the Bras de Caverne River, a tributary of the Rivière du Mât. ...

on Réunion Island)

List

Africa

File:Jezioro Słoniowe (Barombi Mbu) - okolice Kumba - 001304s.jpg, Lake Barombi, Cameroon File:Lac de cratère de Mballang près de Ngaoundéré1.jpg, Lake Mbalang, Cameroon File:Lake Awing 2.jpg, Lake Awing, Cameroon File:Lake Mfou on Mt Mbapit.jpg, Mount Mbapit crater lake, Cameroon File:Lac Tyson.jpg, Lake Tison, Cameroon File:The Amazing Lake Bambili.jpg, Lake Bambili, North West Cameroon File:Monoun.jpg, Lake Monoun exploded in 1984, Cameroon File:Manengouba- lac jumeaux.jpg, Lake Manengouba, Cameroon File:Dendi Caldera.jpg,

Mount Dendi Mount Dendi is a volcano located near the city of Addis Ababa Addis Ababa (; am, አዲስ አበባ, , new flower ; also known as , lit. "natural spring" in Oromo), is the capital and largest city of Ethiopia. It is also served as major ...

double crater lake, Ethiopia (seen from the ISS) File:Wonchi Lake of Ethiopia.jpg, Wonchi crater lake, Ethiopia File:Lac dziani vue.jpg, Dziani Dzaha, Mayotte

Antarctica and the sub-Antarctic islands

Asia

File:Fahey DSCF1827 (6074447178).jpg,

Heaven Lake Heaven Lake ( Korean: , ''Ch'ŏnji'' or ''Cheonji''; zh, 天池, ''Tiānchí''; Manchu: ''Tamun omo'' or ''Tamun juce'') is a crater lake on the border between China and North Korea. It lies within a caldera atop the volcanic Paektu Moun ...

, the crater lake of

Paektu Mountain Paektu Mountain (), also known as Baekdu Mountain and in China as Changbai Mountain ( zh, s=长白山, t=長白山; Manchu: Golmin Šanggiyan Alin), is an active stratovolcano on the Chinese–North Korean border. At , it is the highest moun ...

on the China–North Korea border File:Mount Aso acid lake seen from helicopter by ET.jpg,

Mount Aso Mount is often used as part of the name of specific mountains, e.g. Mount Everest. Mount or Mounts may also refer to: Places * Mount, Cornwall, a village in Warleggan parish, England * Mount, Perranzabuloe, a hamlet in Perranzabuloe parish, ...

crater lake, Japan File:Taal volcano aerial.jpg, Taal volcano, Philippines File:Mount Pinatubo 20081229 01.jpg, Lake Pinatubo, Philippines, formed after the 1991 eruption of Mount Pinatubo

Europe

File:Iceland2009-BradWeber-Kerid.jpg,

Kerið Kerið (; also Kerith or Kerid) is a volcanic crater lake located in the Grímsnes area in south Iceland, along the Golden Circle. It is one of several crater lakes in the area, known as Iceland's Western Volcanic Zone, which includes the Rey ...

crater lake, Iceland

North America

File:Crater lake oregon.jpg, Crater Lake in Oregon, US File:Katmai Crater 1980.jpg, Katmai crater lake, Alaska, US File:Kluft-photo-SodaLake-pano-2018-11.jpg, Soda Lakes maar volcano in Nevada, US File:Irazu crater lake from the mirador by ET.jpg, Irazú crater lake, Costa Rica File:Laguna de Maderas by ET.jpg,

Maderas With a height of , Maderas is the smaller of the two which make up the island of Ometepe, situated in Lake Nicaragua in Nicaragua, Central America. Unlike Concepción, the other volcano on the island, Maderas has not been active in historical ...

crater lake (

Ometepe Island Ometepe is an island formed by two volcanoes rising out of Lake Nicaragua in the Republic of Nicaragua. Its name derives from the Nahuatl words ''ome'' (two) and ''tepetl'' (mountain), meaning "two mountains". It is the largest island in Lake Nic ...

), Nicaragua File:Ilopango caldera.jpg, Lake Ilopango,

El Salvador El Salvador (; , meaning " The Saviour"), officially the Republic of El Salvador ( es, República de El Salvador), is a country in Central America. It is bordered on the northeast by Honduras, on the northwest by Guatemala, and on the south ...

, crater lake File:Coatepeque Vista.jpg,

Coatepeque Caldera Caldera De Coatepeque (Nahuatl ''cōātepēc'', "at the snake hill") is a volcanic caldera in El Salvador in Central America. The caldera was formed during a series of rhyolitic explosive eruptions between about 72,000 and 57,000 years ago. ...

, crater lake

Oceania

File:Satellite view of Niuafo'ou, 2005-03-19.jpg, Niuafo'ou crater lake, Tonga

South America

File:Laguna de Cuicocha 01.jpg, Cuicocha, Ecuador

References

{{Earth's landforms