caldera

This term describes a specific geological feature characterized by a large, basin-shaped depression. It differs from a standard volcanic crater in scale and origin; while a crater is blasted out by an explosion, a caldera is created by the structural collapse of the volcano into its own emptied magma chamber. In a geographical context, these formations often become the sites of large lakes or distinct islands. The term is used strictly in geological and volcanological discourse to describe these massive depressions.