Molten lava, rocks and gas went flying through the air on Hawaii’s Kilauea volcano after an explosion was caused by the partial collapse of a crater wall. The collapse triggered a small explosion, spreading lava and debris around the rim of Kilauea’s Halemaumau Crater, the U.S. Geological Survey’s Hawaiian Volcano Observatory says. Janet Babb, a geologist with the USGS, compared the blast on Sunday to taking a hammer to the top of a bottle of champagne.

“You look at the bottle and you see the liquid, but you don’t see the gas,” she said. “There’s a lot of gas in the lava. And so, when that rock fall hits the lava lake, it’s like the moment you knock the top of the champagne bottle off and that gas is released and it hurls molten lava and rock fragments.” Rocks overhanging the lava lake are altered by gases coming from the lava, Babb said. The rocks eventually give way and collapse into the lava, causing an explosion. The material was hurled about 280 feet skyward, she said. MORE