When Kilauea‘s caldera collapsed in 2018, it came with a sequence of 12 closely-timed eruptions that did not match either of the typical volcanic eruption types. Usually, eruptions are either magmatic — caused by rising magma — or phreatic — caused by groundwater flash-boiling into steam. The data from Kilauea matched neither type.
Instead, scientists proposed a new model for eruption, based around a mechanism similar to the stomp-rockets that kids use. They suggested that, before the eruption, Kilauea’s magma reservoir contained a mixture of magma and a pocket of gas. When part of the magma reservoir collapsed, the falling rock compressed the gases in the chamber — much the way a child’s foot compresses the air reservoir of a stomp rocket — building up enough gas pressure to explosively launch debris and hot gas up to the surface.
The team found that computer simulations of this new eruption model matched well with observations and measurements taken at Kilauea in 2018. Kilauea is one of the most closely monitored volcanoes in the world; although the team suspects this mechanism occurs during caldera collapse of other volcanoes, it’s unlikely they could have pieced together such a convincing case for an eruption anywhere else. (Image credit: O. Holm; research credit: J. Crozier et al.; via Physics World)
