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Drilling deep into dormant super volcano rouses fears and hopes

posted 4 Aug 2012, 12:03 by Mpelembe   [ updated 4 Aug 2012, 12:04 ]

Scientists have begun a deep drilling research project at the site of a large underground volcano near Naples, which, if it were to erupt, could have catastrophic consequences on the densely populated area. While some fear the drilling could wake up the dormant giant, those involved in the project say it is safe and crucial to understanding the nature of the little-studied volcano.

The lively sea front scenes in the outskirts of Naples on the surface differ very little from typical summer days anywhere in the world; children play with friends, couples display their affection and many work on their sun tans.
However, the ground beneath their feet is equally full of life -- one of world's most dangerous volcanoes sits under the densely populated area.

Across the bay of Naples from Pompeii, where thousands were incinerated by Mount Vesuvius, lies a hidden "super volcano" that could kill millions in a catastrophe many times worse than that ancient disaster.

Now scientists plan to drill 3.5 km below the surface to monitor a huge chamber of molten rock and give early warning of any eruption from a collapsed volcanic caldera 13 km (8 miles) wide.

The boiling mud and sulphurous steam holes of an area west of Naples known as the Campi Flegrei or Phlegraean Fields, from the Greek word for burning, are a tourist attraction.

The original, massive eruption tens of thousands of years ago created much of the postcard scenery of the area including the cliffs of the resort of Sorrento.

But the zone of intense seismic activity, which the ancients thought was the entrance to hell, could pose deadly danger.

The Campi Flegrei are a similar phenomenon to the Yellowstone caldera in the U.S. state of Wyoming but of more concern because they are in an area populated by around 3 million people in the Naples hinterland.

"These type of areas can, at their maximum eruptive strength, be the origin of the only eruptions which could have catastrophic consequences globally, having the same intensity as the impact of very large meteorites would have. Fortunately, it is very rare for these areas to erupt at their full capacity, just like it is rare for large meteorites to hit the earth. However, as some of these areas, like the Phlegraean Fields, are very densely populated even small eruptions which can occur more frequently, can pose risks for the population," said Giuseppe De Natale, head of the drilling project, who heads the Vesuvius observatory at Italy's National Institute for Geophysics and Volcanology.

One such impact is thought to have caused the extinction of the dinosaurs 65 million years ago after a huge explosion that plunged the earth into darkness.

The project, funded by the multi-national International Continental Scientific Drilling Programme, however, has run into major opposition from some local scientists who say the drilling itself could cause a dangerous eruption or earthquake.

Benedetto De Vivo, a geochemist at Naples University, has said the drilling could cause an explosion.

The Naples city council blocked the project in 2010 but it resumed on the site of an abandoned steel mill at Bagnoli, west of Naples, late last month after the recently elected new mayor, Luigi De Magistris, gave the go-ahead.

De Natale scoffed at the objections, saying that the drilling was perfectly safe and that similar probes had been sent down by mining projects looking for sources of thermal energy in the 1980s and earlier.

He added that those raising objections were not experts on drilling and that their suggestions of potential earthquakes or escapes of magma or liquid molten rock, had been exaggerated by the local press.

Branding some of the suggestions "laughable", he added that the project's priority will be scientific knowledge and safety of the local population rather than industrial exploitation as in the past.

"The important thing is that simple drilling activity, which does not involve any extraction of fluids, like for example the extraction of oil and gas and which does not involve the injection of fluids, as in the case of stimulated geothermal systems, can under no circumstances cause an earthquake," he said.

He added that drilling is the only way to discover the geological history of the area because successive eruptions buried previous evidence. The probe has already found volcanic rock from a major eruption 15,000 years ago.

De Natale's team has begun drilling a pilot hole at the Bagnoli site, where a long jetty built to load steel is now used by joggers and courting couples enjoying the spectacular Neapolitan sunsets.

The pilot hole is aimed not only at studying the stratification of the area but to establish a deep geological observatory with new instruments which De Natale says are many times more sensitive than those in the past.

The project also aims to study the cause of a phenomenon known as bradyseism which is a gradual raising and lowering of the earth's service because of deep volcanic activity. This is episodic but in the latest phase the ground has risen by 3.5 metres in 15 years, the most since medieval times.

This movement forced the evacuation of 30,000 people temporarily from Pozzuoli in the 1980s and a fishing harbour in the old part of the town was completely abandoned.

Once work is complete on the pilot hole, scientists plan to drill much deeper, to around 3.5 km where temperatures are at around 500 degrees centigrade. But De Natale said this could take another 18 months and the area for the second phase has not yet been decided.

His team has developed new fibre optic sensors able to withstand the extreme heat that would have destroyed earlier electronic equipment.

De Natale says there will be no risk of an escape of magma because the molten chamber is at 7km depth or lower and sensors will give ample warning of temperatures that reach 1,000 degrees centigrade at the molten core.

Local people are divided on whether the drilling could be dangerous.

"There is a very high risk that the drilling can lead to a shift of the earth's surface and if that were to happen rather than helping to predict possible future problems, as they say they want to do, they will instead be creating them," said Pozzuoli student Marco Laporta.

But many seem more sanguine.

"It is not an urgent issue. Already back in the 1980s they said we'd all be blown up but we weren't," said local resident Luigi Bruni.

"We are always asking ourselves whether something is going to happen. Something may happen but if we think too much about it, we will never be able to carry on with our lives. That's the reality and we have to live with it," added local resident Biagio Lucignano.

However, if temperatures of 500 degrees were to be detected, the top of the drilling hole could be closed hermetically in a fraction of a second, De Natale reassured.