Caldera

A caldera is a large, cauldron-like hollow that forms in the immediate aftermath of a volcanic eruption that empties a magma chamber beneath a volcano. Rather than being blasted out by an explosion, a caldera forms when the ground above the drained chamber can no longer support its own weight and collapses inward, sometimes producing a hollow dozens of kilometers across, so a caldera is really a form of large scale subsidence rather than an ordinary volcanic crater. Caldera forming collapses of this scale are rare: only nine occurred worldwide between 1911 and 2022, most recently at Kilauea in Hawaii in 2018 and at Hunga Tonga-Hunga Haapai in 2022. The word comes from the Spanish caldera, cooking pot, ultimately from Latin caldaria, and was brought into geology by the German geologist Leopold von Buch after he observed collapsed volcanic hollows on Tenerife and La Palma during an 1815 expedition to the Canary Islands.