Target: Italy’s Campi Flegrei

Borehole to Probe Volcano

Italy’s Campi Flegrei, located just west of Naples, may be home to the most dangerous volcanoes on earth – which is saying something considering Mount Vesuvius is a mere 30 kilometers away.

You’d have to be crazy to drill into the middle of it.

Christopher Kilburn
Christopher Kilburn
Juergen Thurow
Juergen Thurow

Geology professors Juergen Thurow and Christopher Kilburn may be just that crazy.

They’re on a mission: The area has undergone two episodes of uplift since the late 1960s (1968-72 and 1982-84), and the two University College, London professors want to know why.

In both occasions, according to Kilburn, a circular area about 10 kilometers across bulged upwards. As a result, the port of Pozzuoli, at the center of the bulge, now stands about three meters higher out of the water than it did in 1968.

Here’s the concern: The uplifts are the first to have occurred since 1538.

“Hence,” says Kilburn, a research fellow in the Department of Geological Sciences at the college, “the resumption of uplift may indicate that the volcano is gradually preparing for another eruption. We can’t be sure, but we must be prudent.”

And that means drilling must commence to analyze the patterns of uplift and of fracturing of the crust (detected as small earthquakes) to better understand what has been causing the uplifts – and when, if at all possible, to predict when another one might occur.

Which is the main, but not only, reason for doing this.

“There are two aspects, scientifically speaking,” says Thurow, a geological sciences professor at the school.

“Obviously, the first has to do with another eruption and if the area is under any immediate danger,” he said, “but also, because it gives the scientific community the opportunity to show off the advancement in drilling technique.”

And why that’s important, he says, is because Campi Flegrei is such a large area – 12 kilometers wide, meaning it can be an amazing canvas for geologists to understand “how rocks behave.”

The Bigger Picture

It is that first part, though – the predictive element – that is the sexiest and the one that makes headlines. And to that extent, both want to temper the anticipation.

“There is not going to be a large interruption” anytime soon, Kilburn says, emphatically.

And this is a serious point for both Kilburn and Thurow, as the disinformation and irrational fear of erupting volcanoes and thousands of people fleeing city streets under a volcanic ash cloud, while the most dramatic angle, is not something they want to lend credence to – or even talk about very much.

“We are not saying something will happen next Friday,” Thurow says. “We are drilling there as it will give us a unique chance of understanding a bigger picture.”

The bigger picture is this: Bordering to the west of Naples in southern Italy, Camp Flegrei (“Burning Fields”) is dominated structurally by a giant caldera, 12-15 kilometers, and has been the site of volcanic activity for at least 50,000 years. The eruptions, 56 in all, have included one that was only slightly smaller than the eruption at Vesuvius, which leveled Pompeii and Herculaneum.

These episodes of uplift do indicate the approach to an eruption, according to Thurow and Kilburn, but the outburst is expected to remain within the range of sizes shown by the 56 previous events.

What makes it important now is that eruptions are usually separated by centuries, not years.

Something, it appears, is happening.

Kilburn and Thurow talk about Campi Flegrei with a degree of pride, especially with Vesuvius being so close. Listening to them talk about the two sites is like listening to a debate over whether Mickey Mantle or Willie Mays was the better baseball player.

They note that Campi Flegrei and the region immediately to the north, in aggregate, have had super-eruptions through the centuries 100 times that of the A.D. 79 eruption of Vesuvius. The last of these super-eruptions occurred 39,000 years ago and produced the Campanian Ignimbrite.

Looking for Answers

There’s much to be learned.

When the drilling begins – a smaller borehole later this year, a larger one before next April – deposits from some or all these eruptions will be collected so as to provide new information on their extent, evolution and potential environmental and climatic impact. This needs to be done, says Kilburn, because material from these eruptions is poorly exposed on land.

“To interpret patterns of uplift, we need to know the physical properties of the rocks that are being deformed,” Kilburn said.

Although there is information at the surface, there is no direct data about how they behave under pressure – at depths of kilometers below the surface – and at the higher temperatures (of 300-400 C) that might prevail at such depths.

The boreholes will allow them to:

  • Obtain samples of the rocks at depth, at which point their physical properties will be measured in a laboratory under appropriate pressures and temperatures.
  • Measure the state of stress in the crust with depth and also its permeability and porosity.

“The measurements,” Kilburn said, “will improve our knowledge of how easily fluids (e.g., meteoric water) can circulate through the crust. These data can be used to assess the potential of developing geothermal energy systems in Campi Flegrei.”

The drilling was postponed due to political concerns involving a local mayoral election, but they’re somewhat reluctant to get into it.

“There were questions about safety,” Kilburn said, “even though the risk analysts had been done.”

And here, both scientists, reminisce about the frustration of dealing with elected officials whose concerns were more political than scientific (Sound familiar?). They decided the best recourse was to put a hold on the project until after the election, which they did.

Things have calmed down since, in part because they moved the drilling site.

“The change in location was made but only for expedience,” Thurow said.

“Nobody is interested in the land where we will now drill,” Kilburn says, adding, “by pure coincidence, it will be a better location.”

And while this is not the first continental drilling into a volcano, it is nonetheless dangerous, exciting and, in many ways, unchartered territory.

For Kilburn and Thurow – for many, actually – Campi Flegrei is the stuff of legend.

According to Greek mythology, Hephaestus, the god of fire (Vulcan is the counterpart in Roman mythology), made his home in the general region and where a battle of epic proportions took place between the Titans and the world's most powerful deities that shook the earth. Myth also has it that the entrance to Hades was also here, hidden beneath a serene lake.

“It’s an extremely exciting area,” Thurow said. “The Romans were active there. It’s a little old port.”

And then, perhaps thinking about the location so close to the romance of Naples, he laughs.

“It’s better than drilling in Greenland.”

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ACE 2011 Presentation...

Juergen Thurow, geological sciences professor at University College in London, England, will present a special lunchtime lecture on the Campi Flegrei drilling project during the AAPG International Conference and Exhibition in Milan.

Thurow’s talk, “Drilling Into the Heart of a Volcano: Campi Flegrei, Southern Italy,” will be offered during the lunch hour on Wednesday, Oct. 26.

His is one of two special lectures that day – the other, by author Michael Welland, is titled “Granular Matters” – that will be offered along with a complimentary lunch for attendees in the Milano Convention Centre’s exhibition hall.