UH expert provides insights on Kīlauea’s towering lava fountains

The ongoing eruption at Kīlauea continues to spark interest with many flocking to the area to witness the on-and-off episodes and the lava fountaining associated with the volcanic activity.

Steven Lundblad, a professor at the University of Hawaiʻi at Hilo in the Geology department helps answer some questions surrounding the nature of the eruption and insights into the towering lava fountains.

This latest eruption started just before Christmas 2024. As of today we’ve had 23 episodes of fountaining associated with that eruption.

Why on-and-off eruptions have continued since December 2024

“What tends to happen is the pressure builds up below the summit of Kīlauea because there isn’t an outlet. At some point the magma makes it to the surface and since it has a fair amount of trapped gas in it. It is erupted out in a fairly explosive manner,” said Lundblad.

Fountains have reached heights of up to 1,000 feet during some of the episodes.

“After that gas is kind of released and some of the pressure is released then the lava comes out and tends to cap over the top and that cycle restarts. So we’re kind of in this repeatable pattern where about once a week we have an eruptive cycle and then in between there’s enough of a kind of a cap on that magma chamber to kind of start that pressure building again,” he said.

What leads to an eruption?

There are a host of different types of effects and parameters that are measured to both predict when the eruption might occur, and tell the story about what happened during the eruption.

“Currently, the best indicator of what’s happening with the eruption and whether or not it’s going to erupt is the ground tilt and that’s essentially measuring the deformation of the ground surface,” said Lundblad. “You can think of it like a balloon where as the pressure increases the surface moves up and expands.”

“You can kind of imagine the ground tilt being related to blowing up a balloon where when the pressure is building the ground surface moves up and away from the summit and causes the ground to be higher in some places than it would be otherwise. What seems to happen is when it reaches a certain level of tilt then we get an eruption and the cycle starts over,” he said.

According to Lundblad, the ground deformation graphs at this point show a sawtooth pattern where the ground tilt increases over the course of a week or so. The eruption happens, it drops and then immediately it starts to rebuild that tilt or the ground deformation again, he said.

How UH Hilo scientists work on forecasting future eruptions ?

Scientists with the USGS Hawaiian Volcano Observatory collect samples, while crews at UH Hilo help them by looking at the chemical composition of the material that comes out to see how the eruption is evolving over time.

“And so that’s a little bit of a way to predict the longer-term processes that might be going on for future eruptions whether within this eruption cycle or down the road and how they compared to last month, last year, five years ago, 10 years ago and what might be changing at the volcano,” said Lundblad.

The current eruption follows a similar pattern to some of the longer lived eruptions at Kīlauea.

“When Puʻu ʻŌ’ō started erupting in 1983 and it erupted for 35 years—the first initial phases of that eruption had many high fountaining episodes before it kind of settled down into a pattern where it was lava flows coming out and then running down to the ocean and many people are familiar with that because it was a great place to go look at lava,” said Lundblad.

The same thing happened in 1959 at Kīlauea Iki. “That eruption occurred for about a month or so and it was punctuated by a whole series of high fountaining events with this. And then in 1969 at Mauna Ulu, again the early phases of that eruption had kind of this episodic high fountaining event. So it’s possible that the volcano will continue to erupt at the summit for a long period of time. And maybe we won’t see the similar type of high fountaining but we may just continually have lava flows building up the lava lake that exist there.”