Which volcano type is formed by collapse of a magma chamber after eruption?

Which volcano type is formed by collapse of a magma chamber after eruption?

• A. Stratovolcanoes
• B. Shield volcanoes
• C. Volcanic domes
• D. Calderas

Answer: (D)

When a magma chamber is largely emptied by a major eruption, the ground above it can no longer be supported and the roof collapses downward, creating a broad, circular depression known as a caldera. This collapse happens after the eruption has evacuated much of the magma, so the surface features form not from lava piling up but from the chamber essentially caving in. Calderas are typically much larger than a simple crater and can later host lakes or even become sites of resurgent activity. This mechanism is different from how stratovolcanoes form, which build up through many eruptions that lay down alternating layers of lava, ash, and other material. It’s also different from shield volcanoes, which grow broad, gentle slopes from steady, low-viscosity lava flows, and from volcanic domes, which are built by viscous magma that extrudes and piles up near the vent rather than collapsing the chamber.

When a magma chamber is largely emptied by a major eruption, the ground above it can no longer be supported and the roof collapses downward, creating a broad, circular depression known as a caldera. This collapse happens after the eruption has evacuated much of the magma, so the surface features form not from lava piling up but from the chamber essentially caving in. Calderas are typically much larger than a simple crater and can later host lakes or even become sites of resurgent activity.

This mechanism is different from how stratovolcanoes form, which build up through many eruptions that lay down alternating layers of lava, ash, and other material. It’s also different from shield volcanoes, which grow broad, gentle slopes from steady, low-viscosity lava flows, and from volcanic domes, which are built by viscous magma that extrudes and piles up near the vent rather than collapsing the chamber.