The sounds of bursting lava are music to a volcanologist’s ears. Eros and reverberating caterpillars can help reveal what goes into the depths of a volcano’s belly.
Listening to Kīlauea Volcano in Hawaii has allowed researchers to track magma temperature and volcanic gas migration as they bubble to the surface.
The findings have revealed something unexpected about the famous 2018 volcano eruption.
“It’s a new look at the dynamics of a really popular volcano,” says Earth scientist Leif Karlstrom of the University of Oregon.
“People could stay near the shore of the lava lake and visit the lava flows that come out. But beneath the surface, there were many more things.”
For 10 years, between 2008 and 2018, Kīlauea volcano experienced gentle eruptions of lava almost continuously.
Then, suddenly, two dozen respirators above the east rift zone exploded, throwing molten rock springs into the air.
The eruption was followed by several years of silence, until September 2021, when the lava sweat began again.
Kīlauea is often said to be the most active volcano in the world, and much of this concern comes from Halema’uma’u crater. This crater is located at the top of the volcano and is filled with a lava lake.
The lava lake is believed to be constantly covered by an underground magma chamber. But it is still largely unknown how these deeper dynamics work.
By placing seismic sensors around the crater, researchers hope to penetrate the boiling hot abyss.
The technique they use is similar to hearing the tone of a half-full bottle when you touch it. As with the bottle, the vibrations that sound from the volcano depend on its contents.
“Once something physically disrupts the magma chamber or lava lake, it moves, and we can measure it with seismometers,” says geophysicist Josh Crozier, also of the University of Oregon.
“During this decade-long eruption, we detected tens of thousands of such events. We are combining this data with a physics-based process model that creates these signals.”
Researchers are still unsure of what the noises mean, but hope to learn Kīlauea’s “melody” so they can better predict when the volcano will erupt again.
Without taking any direct measurements of the lava lake itself, the team has been able to track the gas bubble and changing temperatures over the course of eight active years.
Interestingly, just before the 2018 eruption, the authors did not notice any signs of magma influx into the lava lake.
The temperature and chemistry of the lava lake were largely consistent in 2018. Nothing changed drastically before the eruption.
This means that the magma entry was probably not what triggered the explosion, as the scientists thought.
Instead of the underground magma chamber feeding the lava lake until a sufficiently high pressure was reached, it appears that the explosion occurred from the opposite process.
The lava appears to have drained from the main system and has spread eastward through a 10-kilometer-long underground tunnel. This was probably what triggered the great eruption of the eastern rift, which eventually destroyed 700 houses and displaced more than 2,000 people.
(Gansecki et al., Science, 2018. Photos from the US Geological Survey)
On top: Simplified model of the Kīlauea magma system that feeds the eruption of the lower eastern rift zone east of 2018.
Kīlauea may be one of the most studied volcanoes in the world, but its plumbing is still a mystery.
Researchers still do not fully understand the true nature of the volcano’s lava lake, its rift zone, or its underground magma sources.
The deep reverberation sounds of the lava could one day help us to hear what we are not able to see.
The study was published in Science Advances.