Caldera

A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber. Its diameter is many times larger than that of a typical volcanic crater; typically, it is a kilometer or more across. Calderas are usually formed by one of two mechanisms:

• Collapse Caldera: This type of caldera forms when a large volume of magma is erupted rapidly from a shallow magma chamber. The roof of the magma chamber, no longer supported by the underlying magma, collapses inward. These collapses can be sudden and catastrophic, leading to large-scale eruptions and the formation of steep-walled depressions.

• Explosion Caldera: Although rarer, some calderas are formed by extraordinarily violent explosive eruptions. These eruptions eject vast quantities of rock and ash, sometimes excavating a large depression in the ground. The scale of these explosions is typically much larger than those associated with stratovolcanoes.

Calderas can fill with water, forming caldera lakes. Over time, post-caldera volcanism can occur within the caldera, creating new volcanic cones, lava flows, and hydrothermal features. Calderas are of significant geological interest and pose potential hazards due to the possibility of future eruptions. They are also important geothermal resources in some areas. The term "caldera" comes from the Portuguese word for cauldron.