When studying a monster volcano, poke softly with a sensitive stick

Sometimes the best thing you can do with a monster is to poke it with a stick. Gently, of course. Prod too hard, and he might roar back in your face. That’s the chance scientists are taking in Italy, where they are drilling right into the heart of a restive supervolcano to see what it might do.

Volcanologists like to work in southern Italy, and not just for the wine. Here, where the crustal plate carrying Africa dives beneath the plate carrying Europe, volcanoes bubble up like marinara on the stove. From Rome southward, the country is studded with volcanoes, from the fire fountains of Stromboli to the iconic peak of Vesuvius. West of Naples lie the Phlegraean Fields, a landscape of steam vents and boiling mud pots where the Roman god Vulcan was said to live. Nearby is Lake Avernus, where Virgil sent Aeneas descending to the underworld.

In the midst of this hellish landscape sits a volcano less well known than Vesuvius, yet far more deadly. The Campi Flegrei caldera, along the Bay of Naples, is the collapsed remains of a massive mountain that exploded about 39,000 years ago.

It’s hard to exaggerate just how bad that day was. Towers of ash rose 40 kilometers or more into the air, practically to the edge of space. Fragments of rock bulleted eastward, showering the landscape from Greece to Bulgaria to Russia. Within months temperatures probably plummeted in a frigid “volcanic winter.” Some speculate that the disaster may have even led to the extinction of the Neandertals, who at the time were locked in an epic battle with Homo sapiens for mastery of the continent. (A recent study of ash layers in archaeological caves, though, suggests those other hominids made it through the eruption just fine.)

In short, it was the worst eruption in Europe in the last 100,000 years or more.

Since its explosion, Campi Flegrei has burped out a string of smaller eruptions, the last coming in 1538 when it built the cinder cone of Monte Nuovo. Starting in the 1960s, the caldera began rumbling again. Between 1982 and 1984 the landscape lifted up by as much as four meters. Earthquakes began rattling the nearby town of Pozzuoli. Worried that magma might once again be flooding just below the surface, officials evacuated the city for months.

Things eventually quieted down, but in 2005 the ground started rising again. Volcanologists spotted a lot of changes at the volcano, from how fluid flowed through underground pipes to the temperatures of the steam venting out. In a paper to appear in Geology, a team led by Giovanni Chiodini of Italy’s national institute of volcanology and geophysics suggests that the pattern of activity matches what you’d expect if magma were being injected into the shallow crust from deeper in the Earth. In other words, the monster may be awakening.

And now volcanologists are poking their sticks into Campi Flegrei’s heart. In July, they began a long-delayed project to drill several holes deep into the caldera. It has taken so long to get going because critics have questioned what might happen if the drill hole accidentally causes superhot fluids or gases to come in contact with magma. Could the drilling even trigger an eruption?

It’s a sensitive topic in Italy, which is still reeling from a 2009 earthquake that killed more than 300 people and ruined much of the medieval town of L’Aquila. In the wake of that disaster, six scientists and one government official were charged with manslaughter, for not properly conveying seismic risks to local residents. The trial is ongoing.

Perhaps not surprisingly, more than two years passed before the volcano drillers could get their project approved. Now, though, the first hole is more than 200 meters deep, on the way to an eventual goal of 500 meters.

The idea is to switch on the lights and reveal the monster hiding in the dark for whatever it really is. Researchers plan to map the three-dimensional structure of the caldera, as well as install instruments down the drill holes to better monitor earthquakes and other signs of unrest. Such information will help volcanologists better assess the risks of future eruptions, including those like the one that devastated Europe 39,000 years ago.

Other volcanologists have drilled into active volcanoes before, including projects in Hawaii and Iceland that hit magma. In each case, molten rock oozed a little way up the drill hole before stopping. Nothing erupted.

Sometimes, taking the risk is worth it. Sometimes, you just have to poke the monster to make sure he is really sleeping.

Then again, if Campi Flegrei does erupt, more than 3 million people will be in danger.

SN Prime | August 20, 2012 | Vol. 2, No. 32

Alexandra Witze is a contributing correspondent for Science News. Based in Boulder, Colo., Witze specializes in earth, planetary and astronomical sciences.

More Stories from Science News on Earth