A large basin-shaped volcanic depression with a diameter many times larger than included volcanic vents
; may range from 2 to 50 km across. Commonly formed when magma
is withdrawn or erupted from a shallow underground magma reservoir
. The removal of large volumes of magma may result in loss of structural support for the overlying rock, thereby leading to collapse of the ground and formation of a large depression. Calderas are different from craters, which are smaller, circular depressions created primarily by explosive excavation of rock during eruptions.