I imagine volcanoes as orchestras composed of hundreds of different instruments.

 

Forecasting eruptions isn't about hearing the music.

 

We already do that:

• seismometers sense the cracking of rock as magma ascends

• ground sensors and satellites can track shifts in the crust, indicating where magma is flowing

• gas detectors reveal when magma rises to shallow depths, depressurizes, and emits noxious fumes

The challenge comes in knowing how the symphony will develop to a climax, long before it gets underway.

 

Today, at the most comprehensively monitored volcanoes, the best that volcanologists can normally offer is not prediction but a form of acute caution.

 

Often, alert systems - including those used by the U.S. Geological Survey - notify the public if a volcano is exhibiting heightened or escalating unrest.

 

But that doesn't mean an eruption is imminent.

"Only 50% of volcanic unrest that looks like it's going to be an eruption ends up in an eruption," said Jessica Johnson, a geophysicist at the University of East Anglia in England.

On the other hand, some volcanoes prefer to ambush us, even when smothered in instrumentation.

 

Pockets of highly pressurized water trapped just below the surface can be heated by adjacent bodies of magma. If that pocket ruptures, a dangerous steam explosion follows, which can then unleash imprisoned magma.

 

This type of eruption often occurs with no discernible warning signs, and it's like a land mine going off next to a buried mountain of dynamite.

More predictive detail can come if a volcano has been studied over the course of several eruption cycles.

 

At certain peaks, such as Italy's Stromboli and Etna volcanoes, which regularly spout fountains of lava, scientists can confidently forecast an outburst.

"We have systems that can tell us that in a few hours, the volcano will erupt," said Maurizio Ripepe, a geophysicist at the University of Florence.

Using seismology and ground deformation measurements, scientists at other volcanoes, including Hawai'i's Kīlauea and those on Iceland's Reykjanes Peninsula, can track magma migrating underground with such staggering precision that they know exactly where it will emerge as lava, to within an hour or so.

But such precise forecasts are "relatively unusual," said Tom Winder, a volcano seismologist at the University of Iceland.

These are frequently active volcanoes, unlikely to produce a major explosive event, and people in surrounding communities generally know to be wary of them.

 

In most other cases, the earliest warning times - perhaps an hour or so before the eruption - aren't always enough to get people to safety.

 

Forecasting eruptions is a big ask because volcanoes cannot be reduced to simple models. They're baroque geologic beasts with hidden, labyrinthine plumbing.

 

Twenty years ago, during my first year as a geoscience undergraduate, a lecturer told me that predicting when and where the next major eruption would take place was a pipe dream - the implication being that volcanoes are far too idiosyncratic and mercurial to have much in common with one another.

 

That comment felt off even then.

After all, they are all vessels of immense pressure and heat.

Their schematics may differ.

 

But molten rock flows through all of them, and eventually, something cracks, breaks, and explodes.

Everyone I spoke to agreed that scientists still need to crack a vital piece of the volcano forecasting puzzle.

"We don't even fully understand the underlying physics," Roman said.

What causes a magma reservoir to transition from a stable state to catastrophic failure?

"They have to have shared physics," she said.

If those underlying equations can be discovered, perhaps we can apply them to all volcanoes and output values that tell us, with high accuracy, when the next eruption is due, and what its shape may be.

 

Scientists have already identified some of these governing equations, but they only apply after eruptions have begun.

 

Using more than a century of observations, researchers have largely derived the physics of volcanic hazards - particularly lava flows and pyroclastic flows.

 

For examples,

the Navier-Stokes equations, which describe how fluids of all kinds move, have been successfully applied to both of these hazards, while the heat equation reveals how and when these volcanic fluids cool down.

Today, they allow experts to predict, for specific volcanoes, where outpourings will emerge, how far the different kinds of flows will reach, and how quickly it will all happen.

 

This work saves lives, but it's a fraction of the forecasting dilemma.

 

Using our weather analogy, this is like saying,

"Once the rain starts to fall, we can forecast what watersheds might flood," Poland said.

Knowing when the storm will start requires getting at the subsurface physics of magma reservoirs.

 

For now, eruption warnings are based on recognizing patterns in measurable geophysical signals, such as an escalation of seismic activity, that precede eruptions. But correlation isn't enough for prediction if the patterns aren't consistent, which is often the case.

"What we're trying to do is looking at the causative relationships there... to understand the physics," Johnson said.

 

"If you understand what those patterns mean, [then] when those patterns change, we're not that stuck."

Johnson is part of a new project named Ex-X: Expecting the Unexpected, a multidisciplinary effort led by the University of Bristol to investigate the drivers of dangerous volcanic escalations.

 

Researchers are focusing on the volcanoes of the Eastern Caribbean, which erupt relatively frequently and can quickly transition from effusive-style, lava-heavy eruptions to sudden, catastrophic, explosive ones.

 

La Soufrière, on the island of St. Vincent, provided a recent example of this: In December 2020, the volcano began expelling a viscous mass of lava, which continued for several months.

 

Then multiple explosions threw pyroclastic flows down its slopes.

As part of this work, hundreds of seismometers, as well as networks of fiber-optic cables, will be used to record even the tiniest of earthquakes, during periods of tranquility and unrest.

 

This monitoring effort will be aided by machine learning programs that will be taught to identify minute shifts in the seismic soundtrack of these volcanoes.

 

In recent years, these programs have been used to process a huge volume of data far more proficiently and efficiently than scientists can manage alone.

 

This work has already revealed myriad previously hidden magmatic pathways beneath volcanoes while also permitting scientists to track, almost in real time, magma barreling through the crust.

 

The idea of Ex-X is to gain unprecedented detail on how tiny changes in the behavior or position of magma can lead to eruptions. Those insights can, in turn, illuminate some of the underlying physics.

 

All these Caribbean volcanoes, diverse though they may be, could have a shared set of fluid dynamics equations.

However, seismology won't be enough by itself.

"We lack the physical understanding of what exactly is going on in a magma chamber," Poland said.

What causes the unstoppable nucleation of bubbles within a body of magma, which can propel hot, buoyant magma through the crust above with soda can–like effervescence?

 

What combination of molten rock, crystals, and gas is primed to trigger an eruption?

 

What drives an eruption to switch from expelling oozing lava to blasting ash and rock into the sky?

Geochemistry is essential to this effort, too.

 

Today, scientists scoop up lava or ash, fresh or ancient, around volcanoes - both during an eruption and in the interregnum between them - to identify subtle changes in chemical makeup.

 

Scientists use sophisticated numerical models to simulate volcanic viscera, but this is still educated guesswork. Laboratory experiments, though, may be able to ground these models.

 

Replicating the most extreme phenomena in laboratory settings is not easy.

 

But in successful experiments in the fall of 2025, scientists re-created the conditions present at the birth of planets, complete with simulacra of magma and miniature hydrogen atmospheres.

"You can't just make a magma chamber at the surface of the Earth," Poland said.

 

"But we're a heck of a lot closer to that sort of thing than we were a while ago."

Ideally, volcanologists want to try something else truly ambitious:

"Drill all the way down to where there is some magma sitting at depth, and really see these processes in situ, rather than just seeing the results of them," Winder said.

That is one of the objectives of the Krafla Magma Testbed in Iceland.

 

This literally groundbreaking facility is set to become the world's first direct magma observatory. 

"There's no reason we can't think that at some point in the future, we can have volcano forecasts that are like weather forecasts," Poland said.

But deriving a unified theory of volcanism will require a geologic Manhattan Project.

 

First, a constellation of highly diverse volcanoes will need to be slathered in geophysical instrumentation and consistently monitored over multiple eruption cycles - meaning many decades.

"You would like to think, OK, volcanoes are pretty well monitored. But they're not," Roman said.

 

"There's a handful of Cadillac volcanoes that have permanent networks."

Even many of the United States' most dangerous volcanoes, along the Cascades in the Pacific Northwest (home to the notorious Mount St. Helens, for example, and the precarious Mount Rainier), are only partly covered in a limited number of sensors.

 

With such a torrent of geophysical and geochemical information, scientists (aided by machine learning) can determine the commonalities that would allow them to derive foundational geophysical laws.

 

Then they can build the archetypal volcano model:

one that is very generic but can be layered onto any volcano in the world.