Caldera

volcanoes · earth science · geology · dramatic landforms

Magma chamber collapse. When a volcano erupts and shoots out huge amounts of magma really quickly, the underground chamber that held all that melted rock becomes mostly empty. Without the magma filling it up, the walls and ceiling can't support their own weight, so the ground above caves in like a sinkhole.

Huge hollow bowls. Calderas can be enormous, with diameters spanning dozens of kilometers across. They're actually a type of sinkhole formed by collapse, not by an explosion punching a hole like you might imagine.

Super rare events. Even though volcanoes erupt thousands of times per century, calderas form only a few times every hundred years. They're so uncommon that only nine caldera collapses happened between 1911 and 2022.

Recent examples. Kīlauea in Hawaii collapsed in 2018, and Hunga Tonga, Hunga Haʻapai in the Pacific collapsed in 2022. These are the most recent calderas we know about.