Volcanic Crater

A volcanic crater is an approximately circular depression in the ground caused by volcanic activity, typically bowl shaped and containing one or more vents. During an eruption, magma and volcanic gases rise from an underground magma chamber through a conduit until they reach the crater vent, where the gases escape into the atmosphere and the magma erupts as lava. During certain explosive eruptions a volcano magma chamber can empty enough that the ground above it subsides, forming a larger type of depression known as a caldera.