Kilauea, active Hawaiian volcano, could erupt like a ‘stomp-rocket toy,’ new study suggests

(KAUAI, Hawaii.) — Scientists may have found the mechanism behind the unusual explosive eruptions seen at one of the most active volcanoes in the world.

Kilauea, located at Hawaii Volcanoes National Park on the Big Island, experienced at least a dozen instances in 2018 when lava was spewing from the crater like a “stomp-rocket 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 that lava flow that year that destroyed more than 600 properties, Josh Crozier, a geologist at Stanford University and lead researcher of the study, told ABC News.

The eruptions — sometimes up to 30 feet high — were atypical because explosive eruptions are typically driven by either rising molten rock — magma — or by expanding steam from magma heating underground water. The stomp-rocket toy mechanism geologists believe caused the 2018 eruptions likely stemmed from the collapse of the magma reservoir, which suddenly increased the pressure of gas trapped in the chamber and lead to an explosive eruption.

A combination of seismic and geodetic instruments indicate a large, abrupt inflation of all the 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 quite different from a typical spectrum of groundwater-driven, magma-driven eruptions,” he said.

The findings also may help to 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, it creates aviation hazards, falling ash and the release of gases, Crozier said.

Abnormal eruptions at Kilauea have been documented as early as the 1920s, which began a series of relatively large explosive eruptions, said Crozier, who conducted the study during his time with the U.S. Geological Survey.

In 2018, the extra explosive activity at the summit helped to drive the heavy outpouring of the magma, Crozier said. The lava then poured along the east rift zone of the volcano, damaging hundreds of homes on its path toward the ocean, he added.

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

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

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

“Importantly, they can happen in potentially conditions where you wouldn’t otherwise necessarily expect an explosive eruption to come out of the volcano summit,” Crozier said of the unique mechanism. “So it’s certainly something to be aware of is a possibility in these volcanoes.”

Understanding the dynamics of plume formation, especially those that contain hot gas and rock particles that can be hazards to human health, are important to forecast to residents living nearby, the researchers said.

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