Calderas are large volcanic depressions, roughly circular in
shape, from 1 to 250 km in diameter. Structures less than 1 km
diameter are termed maars, and those over 250 km volcanic
depressions. The 1968 eruption of Fernandina volcano in the
Galapagos Islands resulted in about 300 m of caldera collapse.
The volume of the collapse was over 100 times greater than the
volume of lava erupted during the event. Examples of Calderas
Krakatau (Indonesia), Batur (Indonesia), Deception Island
(Antarctica), Ambrym (Vanuatu).