Kilauea, the active Hawaiian volcano, could erupt like a ‘stub rocket,’ a new study suggests

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 its crater like a “stomp rocket toy,” a children’s toy in which a rocket is launched into the air after stomping over the release mechanism, according to a paper published Monday in Nature Geosciences.

The unusual eruption behavior likely contributed to the severity of that year’s lava flow that destroyed more than 600 properties, Josh Crozier, a geologist at Stanford University and lead researcher on the study, told ABC News.

The eruptions – sometimes up to 9 meters high – were atypical because explosive eruptions are typically caused by either rising molten rock – magma – or by expanding steam from magma heating underground water. The stump-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 indicate a large, abrupt inflation of the entire ground around the magma reservoir, while infrasound measurements that essentially measure low-frequency sounds suggest a drop in air pressure, Crozier said.

“It’s really very different from a typical spectrum of groundwater-driven, magma-driven eruptions,” he said.

The findings may also help explain the formation of atmospheric plumes of hot gas and rock particles erupted by the volcano, the researchers said.

When the plumes are that high, they create aviation hazards, falling ash and the release of gases, Crozier said.

Anomalous eruptions at Kilauea have been documented as early as the 1920s, kicking off a series of relatively large explosive eruptions, said Crozier, who conducted the research during his time at the US Geological Survey.

In 2018, additional explosive activity at the summit helped drive the heavy magma outpouring, Crozier said. The lava then flowed down the volcano’s eastern rift zone, damaging hundreds of homes on its path to the ocean, he added.

Each time a collapse occurred at the summit, it pushed the explosive plumes upward and increased the pressure in the magma reservoir at the summit, which then increased the rate at which the magma was pushed out, Crozier said.

The stump-rocket mechanism may not be unique to Kilauea and may also have triggered eruptions at other volcanoes around the world, several of which have occurred in the past century, according to the study.

Similar eruptions at Kilauea could happen in the future, but it would be “very unlikely” in the next decade, Crozier said.

“Importantly, they can happen in potentially circumstances where you wouldn’t necessarily otherwise expect an explosive eruption to come from the top of the volcano,” Crozier said of the unique mechanism. “So it’s definitely something to be aware of that this is possible at these volcanoes.”

Understanding the dynamics of plume formation, especially those containing hot gas and rock particles that can pose a risk to human health, is important to predict for local residents, the researchers said.