Volcanic crater lake

Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption. Lakes in maars 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, groundwater 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, 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. These lakes may become soda lakes, many of which are associated with active tectonic and volcanic zones. ==Examples==

image of Lake Toba, Indonesia, the largest volcanic crater lake in the world A well-known crater lake, which bears the same name as the geological feature, is Crater Lake in Oregon. 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 in the world, 6,893-m (22,615-ft) Ojos del Salado in Chile, 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 in Indonesia 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 suffocated 1,800 people in 1986, and crater lakes such as Mount Ruapehu's in New Zealand often contribute to destructive lahars. ==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/caldera, such as Garibaldi Lake in Canada, Fuji Five Lakes in Japan • Closed atoll 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 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 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, the crater lake of Paektu Mountain on the China–North Korea border File:Mount Aso acid lake seen from helicopter by ET.jpg|Mount Aso 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 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 crater lake (Ometepe Island), Nicaragua File:Ilopango caldera.jpg|Lake Ilopango, El Salvador, crater lake File:Coatepeque Vista.jpg|Coatepeque Caldera, El Salvador, 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 ==See also==