Science

Besides the depleted magma, the reservoir contained magmatic gas and rubble, which the pressure increase blasted through a vent into the crater above. The researchers call this the “stomp-rocket” effect, after the toy launched by stepping hard on an air bag.

“The ‘stomp’ is this whole kilometer-thick chunk of rock dropping down, pressurizing the pocket, and then forcing material directly up,” Crozier said. The tube in this case a 600-meter (2,000-foot) conduit to the surface and the rocket around 3,000 cubic meters (106,000 cubic feet) of particles, around the volume of an Olympic swimming pool, released every second.