Scientists may have discovered the mechanism behind the unusual explosive eruptions seen at one of the world’s most active volcanoes.
Kilauea, located in Hawaii Volcanoes National Park on the Big Island, experienced at least a dozen instances in 2018 of lava spewing from the crater as a “rocket stomp toy,” a children’s toy that involves launching a rocket into the air after stomping on the release mechanism, according to a paper published Monday in Nature Geosciences.
The unusual eruption behavior likely contributed to the severity of this year’s lava flow, which destroyed more than 600 properties, Josh Crozier, a geologist at Stanford University and the study’s lead researcher, told ABC News.
A bird rests on a wire as lava from a fissure at Kilauea volcano erupts on the Big Island of Hawaii on May 19, 2018 in Kapoho, Hawaii.
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The eruptions — sometimes as high as 30 feet — were atypical, as explosive eruptions are usually triggered either by rising molten rock — magma — or by expanding magma steam heating groundwater. The toy-rocket mechanism that geologists believe caused the 2018 eruptions likely resulted from the collapse of the magma reservoir, which suddenly increased the pressure of the gas trapped in the chamber and led to an explosive eruption.
A combination of seismic and geodetic instruments showed a large, sharp swelling of all the land around the magma reservoir, while infrasound measurements, which essentially measure low-frequency sounds, suggested a drop in air pressure, Crozier said.
“This is really quite different from the typical spectrum of groundwater- and magma-driven eruptions,” he said.
Lava erupts and flows from a fissure at Kilauea Volcano in Leilani Estates, on the Big Island of Hawaii, on May 23, 2018 in Pahoa, Hawaii.
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The findings may also help explain the formation of atmospheric jets of hot gas and rock particles erupted from the volcano, the researchers said.
When plumes are that high, it creates aviation hazards, falling ash and outgassing, Crozier said.
Abnormal eruptions at Kilauea have been documented as far back as the 1920s, the start of a series of relatively large explosive eruptions, said Crozier, who conducted the study while working at the US Geological Survey.
In 2018, additional explosive activity at the summit helped spur the strong outpouring of magma, Crozier said. Lava then poured down the volcano’s eastern rift zone, damaging hundreds of homes on its way to the ocean, he added.
Lava is blurred as it erupts from a fissure at Kilauea volcano, above the treetops, on the Big Island of Hawaii on May 17, 2018 in Kapoho, Hawaii.
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Whenever there was a collapse event at the summit, it pushed out the explosive plumes and increased the pressure in the magma reservoir at the summit, which then increased the rate at which the magma was expelled, Crozier said.
The impact rocket mechanism may not be unique to Kilauea and may also have erupted at other volcanoes around the world, some of which occurred in the last century, according to the study.
Similar eruptions at Kilauea could occur in the future, but would be “highly unlikely” in the next decade, Crozier said.
“Importantly, they can happen under potential conditions where you wouldn’t necessarily expect an explosive eruption to come out of the top of the volcano otherwise,” Crozier said of the unique mechanism. “So it’s certainly something to be aware of that there’s a possibility in these volcanoes.”
Lava spews at Kilauea’s East Rift Zone in Pahoa, Hawaii amid eruptions from the Kilauea volcano.
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Understanding the dynamics of plume formation, especially those containing hot gas and rock particles that can pose a hazard to human health, is important to predict for residents living nearby, the researchers said.
