Calderas and Crater Lakes

This group collects the Volcanic Formations subcategory's members whose own description identifies them as a caldera, crater lake or maar, the large collapsed or explosion-formed hollow left behind after a volcanic eruption empties the magma chamber beneath a volcano or blasts out a crater at the surface. These features are grouped together because a caldera and a maar share the same basic origin, a hollow formed directly by an eruption rather than built up by accumulating lava or ash, setting them apart from the constructive volcano-type groups such as the stratovolcano and shield volcano groups above.