[1] They are generally a body of water inside an inactive volcanic crater (crater lakes) but can also be large volumes of molten lava within an active volcanic crater (lava lakes) and waterbodies constrained by lava flows, pyroclastic flows or lahars in valley systems.
[2] The term volcanic lake is also used to describe volcanogenic lakes, although it is more commonly assigned to those inside volcanic craters.
[3][4][1][2] Lakes in calderas fill large craters formed by the collapse of a volcano during an eruption.
Examples: Lakes in maars fill small craters where an eruption deposited debris around a vent.
Examples: These are some examples of rare lava lakes where molten lava in a volcano maintains relative equilibrium, neither rising to overflowing nor sinking to drain away.