What is the main cause of caldera collapsing?

The main cause of caldera collapse is the emptying of a magma chamber beneath the surface of the Earth. When magma is removed from a magma chamber, the overlying rock can no longer be supported and collapses, creating a caldera. This process can be triggered by a number of events, including volcanic eruptions, earthquakes, and changes in the structure of the Earth's crust.

During a volcanic eruption, magma rises from the magma chamber to the surface. This can cause the magma chamber to empty and the overlying rock to collapse, forming a caldera. Earthquakes can also trigger caldera collapse, as they can cause the rock around the magma chamber to become weakened and unstable. Finally, changes in the Earth's crust, such as the movement of tectonic plates, can also cause caldera collapse.