Lava lakes are large volumes of molten lava, usually basaltic, contained in a volcanic vent, crater, or broad depression. The term is used to describe both lava lakes that are wholly or partly molten and those that are solidified. Lava lakes can form in three ways:
- From one or more vents in a crater that erupts enough lava to partially fill the crater
- When lava pours into a crater or broad depression and partially fills the crater
- Atop a new vent that erupts lava continuously for a period of several weeks or more and slowly builds a crater higher and higher above the surrounding ground.
As of 2010 there were five volcanoes with persistent lava lakes in the world:
- Erta Ale, Ethiopia
- Mount Erebus, Antarctica
- Kīlauea, Hawaii
- Nyiragongo, Democratic Republic of the Congo
- Marum, Ambrym, Vanuatu
