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See more in our gallery: 鈥�Cooling it: How molten rock takes on strange new forms鈥�

ON 5 February 252 AD, a violent volcanic eruption of Mount Etna in Sicily sent a wave of lava towards the city of Catania. According to one tale, desperate citizens opened the tomb of Saint Agatha and removed her red veil, which they held aloft in front of the flow. Miraculously the lava halted, sparing the city from destruction.

鈥淚n 252 AD, citizens of the Sicilian city of Catania opened the tomb of Saint Agatha and held aloft her red veil to stop the flow of lava. Miraculously it halted鈥�

Unfortunately, things didn鈥檛 go so well when they tried it again after an eruption in 1669: this time their holy relic let them down and the city鈥檚 harbour was badly damaged.

Yet one out of two isn鈥檛 such a bad record, considering that modern science has little to offer against this implacable force of nature. After all, how do you stop a river of molten rock? Engineers have tried erecting dams, spraying lava flows with seawater, and even blasting the stuff with aerial bombs, but more often than not these attempts have failed. Nor can volcanologists shed much light on the problem, since streams of lava are so difficult and dangerous to study in the first place.

Now a in upstate New York could help. At the Syracuse University Lava Project, geologist Jeffrey Karson and sculptor Robert Wysocki have teamed up to make what they hope will be the world鈥檚 first large-scale lava flows, created on demand and under controlled conditions. They aim to explain how and why lava behaves as it does 鈥� on land or under the sea 鈥� and their project is even attracting the attention of those who want to unravel the mysteries of rocky planets across the solar system. Ultimately though, they want to learn new tricks for tackling lava head-on. Forget holy relics 鈥� their artificial lava flows are a valuable proving ground for geologists鈥� own 鈥渧eils鈥�: technology capable of diverting the hot stuff or even stopping it in its tracks.

The team at Syracuse isn鈥檛 the first to cook up its own lava. The earliest recorded attempts date back to the 18th century, when Scottish geologist James Hall melted small amounts of basalt in a blacksmith鈥檚 forge. His experiments proved that lava cools to form basaltic rock, and settled a debate between Neptunists, who claimed that the rocks were minerals crystallised from the oceans, and Plutonists, who believed that volcanoes were the source.

Since then, scientists have continued to create their own lava flows, sometimes even replacing molten rock with non-lethal stand-ins such as corn syrup or wax. Yet there鈥檚 still one thing that almost all artificial flows have in common: they tend to be on a tiny scale.

Karson and Wysocki are far more ambitious. Wysocki has had a long-standing interest in recreating natural landscapes with scientific accuracy; one previous project used huge industrial fans to sculpt 45 tonnes of sand into indoor dunes. In 2009, inspired by the glowing slag that trickled from the Syracuse art department鈥檚 iron forge, he contacted Karson and together they taught themselves to make lava, drawing on everything from online videos to Chinese research papers. From the start, the pair wanted to work at a scale comparable to natural lava flows. Wysocki found a disused gas-fired bronze furnace and rebuilt it, and their first small batches of molten rock oozed out the following year.

Working in the parking lot behind the art department, they were soon creating flows with hundreds of kilograms of rock. For a raw material, they chose crushed basalt gravel. Heated to 1300 掳C in the furnace鈥檚 bathtub-sized crucible, it melts into a homogeneous basaltic lava, the most common kind on Earth. And since it is almost indistinguishable from anything coughed up by a volcano, the pair began to think how it could help our understanding of real lava.

Understanding lava is a key issue for geologists. The shape, appearance and chemical composition of our planet鈥檚 ancient lava flows provide important clues about Earth鈥檚 past, including its climate, as well as the volcanic events and conditions 鈥� both beneath the crust and on the surface 鈥� that produced the stuff. 鈥淰olcanoes and lava flows provide us with the only available information about the interior workings of a planet,鈥� says Tracy Gregg of the State University of New York at Buffalo.

Yet lava is an incredibly complex material 鈥� a multiphase fluid that combines liquid, gas and solid crystals. Topography, flow rate and the temperature, viscosity and chemical composition of the rock all affect how it moves. Understanding lava means teasing out the importance of each of these factors, says Karson. At the same time, experiments on real flows can be incredibly dangerous. In 1993, for example, six scientists were killed by a sudden eruption during a visit to the crater of Galeras volcano in Colombia. The Syracuse lab would be able to provide answers without the need for geologists to risk their lives.

Karson and Wysocki鈥檚 experiments have another key advantage: sheer scale. Most lab-based lava experiments make no more than a few cubic centimetres of the stuff. With a low volume to surface ratio, these miniature flows cool much faster than the real thing, meaning it is difficult to scale up the results. 鈥淭ests on tiny dribbles of lava are limited,鈥� Karson says. The Syracuse lab, on the other hand, can handle half a tonne of rock at a time, and create flows several metres long.

Their initial study, published in 2012, highlights the benefits that experiments on this scale can bring. Working with a team from the Lamont-Doherty Earth Observatory at Columbia University in New York, Karson and Wysocki mounted thermal and high-resolution cameras on a gantry above the flow to find out the effect of factors such as the temperature and viscosity of the rock on the lava鈥檚 motion. This showed the lava鈥檚 behaviour matched existing models but highlighted the key role that moisture plays in the viscosity of molten basalt (). This is the first time that a flow of this size has been analysed in such detail. 鈥淥ur experiments are the only ones in the world on this scale,鈥� says Karson.

In a recent collaboration with Ben Edwards of Dickinson College in Carlisle, Pennsylvania, the team also investigated how lava interacts with snow and ice, a subject that has received little attention despite more than 200 active volcanoes 鈥� about a third of the planet鈥檚 total 鈥� spending long periods covered with frozen water. These volcanoes can be particularly dangerous, because the combination of ice and molten rock can trigger sudden floods and dangerous explosions of steam, as happened at Eyjafjallaj枚kull volcano in Iceland in 2010.

In test runs, the team poured 300 kilograms of molten basalt onto ice and snow. They were excited to see that where the lava vaporized the ice to steam, it created a froth of rock bubbles known as 鈥淟imu o Pele鈥�. These are sometimes observed in natural flows but have never been recreated on this scale.

One of the most intriguing observations, says Edwards, was that meltwater can form a lubricating layer of steam under the lava, allowing it to hydroplane downhill at impressive speed. Tests show it can cover tens of centimetres each second .

Explosive eruptions

This seems to confirm observations made by Icelandic geologists, and explains the fast-moving lava sheets that Edwards recently witnessed on snowy volcanic slopes in the far east of Russia. 鈥淭he more water you trap, the more potential there is for larger explosive eruptions,鈥� he says.

Studying molten rock combined with snow and ice can also provide details of Earth鈥檚 past, says Edwards. He hopes to use telltale signs of lava-ice interactions as an indicator of past climate, by linking ice-cover on land with ocean temperatures. He has started by detailing the relationship between eruptions in western British Columbia and records of ocean temperatures.

This approach can even help piece together the history of worlds beyond Earth. All rocky planetary bodies are thought to go through a phase of extensive volcanic activity, but so far we have only witnessed eruptions on one other world: Jupiter鈥檚 moon, Io. Beyond that, planetary scientists must rely on the appearance and composition of rock from past eruptions. Edwards believes that the texture and shape of lava formed at Syracuse could help geologists recognise lava-ice interactions on Mars, perhaps helping to pin down details of climate change on the planet.

But Karson and Wysocki don鈥檛 just want to understand the behaviour of lava 鈥� ultimately, they want to control it too.

Compared with other volcanic hazards such as explosions, toxic gas and avalanches, lava causes relatively few casualties because it usually creeps along slowly. Yet when confined to channels or underground lava tubes, flows can move at up to 30 kilometres per hour. In January 1977, for example, a lava lake in the crater of the Nyiragongo volcano at the eastern edge of the Democratic Republic of the Congo broke open and drained downhill at up to 100 kilometres per hour, killing more than 70 people. Certainly, in economic terms, lava is among the most destructive and expensive volcanic hazards. It engulfs everything in its path, igniting buildings and smothering roads and infrastructure under metres of solid rock.

To protect property, engineers have tried throwing up artificial barriers of earth and stone around volcanoes in Italy, Iceland and Hawaii, with varying degrees of success (see timeline). The truth is that the behaviour of lava is predictably unreliable. To halt or divert a flow, engineers must not only consider the local topography but also the eruption rate, temperature and chemical composition of the rock. Not surprisingly, controlling the stuff is more art than science.

The team at Syracuse is now working with geologist Hannah Dietterich, at the University of Oregon in Eugene, to find out what kind of barrier is most effective. Dietterich has tested an adjustable wedge-shaped barrier made from two plates of steel linked with hinges (see photo), constructed for her by Wysocki. With the point facing upstream, Dietterich altered the angle between the plates to see the effect on the flow. Too narrow a wedge, she discovered, and the lava divides around the barrier and reforms. Too wide, though, and it piles up in front of the barrier until it overflows. But at certain angles her prototype barrier could halve the speed of the flow. The trick, she says, is to divide the lava into smaller streams whose edges cool and harden before they can recombine. 鈥淚f it splits up, the flow slows down,鈥� she says.

These results seem to match historical accounts from volcanoes where barriers have been tested, Dietterich says, adding that the consequences of bad design can be serious: multiple flows striking a barrier can join together and accelerate. There is evidence of this from an eruption of Kilauea in Hawaii. 鈥淲e suspect it may have made the lava go further,鈥� she says. Some sort of 鈥渓eaky鈥� design 鈥� a series of smaller barriers or obstacles, perhaps 鈥� may be effective at turning a single flow into smaller branches that cool faster.

Dietterich will continue these studies early next year, when she will examine the behaviour of split flows, merging flows and the 鈥渂ow waves鈥� that form upstream from obstacles. Yet it turns out that there could be another way to take control of lava.

Imagine a chemical that could trigger the transformation of molten lava into solid rock. Gregg and Karson are starting to investigate whether additives can increase the viscosity of lava so much that it slows, cools and solidifies. Preliminary experiments at Syracuse using crystals of magnesium silicate, known as olivine, show that even in low proportions, it can make a flow thicker and stubbier, as the olivine provides nucleation points for basalt crystals. Tests have also shown that stainless steel pellets have a similar effect. In theory, adding enough of these materials to lava could divert or even stop a flow, says Karson. However, he admits that dumping a load of 鈥淟ava-Stop鈥� from a helicopter may not yet be realistic.

Besides, says lava specialist Michael James of Lancaster University, UK, impressive though the Syracuse experiments are, they are still no bigger than a single tongue or 鈥渓obe鈥� of lava in a real volcanic flow. 鈥淭his might be able to show something new, but you can鈥檛 actually scale that up to flows that are a metre or tens of metres thick. There is a real difference.鈥�

Perhaps not for much longer. Karson and Wysocki plan to use a larger coke-fired blast furnace capable of melting more than 2 tonnes of basalt every hour. It will be able to create a continuous flow of lava that is limited only by how fast they can feed the furnace. 鈥淭his will be interesting scientifically, since it will mimic the accretion of flow fields in places like Hawaii and Iceland,鈥� says Karson.

They also want to make new forms of lava, including magnesium-rich komatiites similar to those found on the moon and early Earth, and silica-rich basalts like those on Mars. But for now, they will stick with plain old basalt 鈥� and continue to let visitors roast marshmallows and hot dogs on the glowing rock. 鈥淧eople are always stunned,鈥� says Wysocki. 鈥淚鈥檝e seen a four-year-old standing beside a postdoc, and the look on both their faces is complete awe.鈥� Even after three years of fashioning flows, Wysocki isn鈥檛 immune to the effect. 鈥淚鈥檝e seen it over 100 times,鈥� he says, 鈥渁nd every time I鈥檓 like, damn, that鈥檚 lava.鈥�