Work continues on the super volcano at Naples amid the usual
controversy. The only real super volcano is the one in Sumatra that
evacuated a large lake. The others have the footprint without an
equivalent evacuation that I have noted anyway. They are all
chronically active of course, but at a low level. Thus we get a
nasty event every few years but possibly avoid an event that is a
global catastrophe.
The major events look great in the geological record but also appear
to be quite survivable. The truth is that we still lack realistic
bounds in time and space when it comes to understanding volcanoes.
We should have learned after Mt St Helen’s to recall our real
ignorance when mother nature comes out to play.
In the meantime, the real threat continues to be Mt Vesuvius. An
exclusion zone should be established and present land owners
encouraged to retreat from it. It is an obvious and known danger
best simply avoided.
"Super
volcano", global danger, lurks near Pompeii
By Antonio Denti
POZZUOLI, Italy, Fri
Aug 3, 2012 12:39pm EDT
(Reuters) - Across the bay of Naples from Pompeii, where
thousands were incinerated by Mount Vesuvius in 79 AD, lies a hidden
"super volcano" that could kill millions in a catastrophe
many times worse, scientists say.
The boiling mud and sulphurous steam holes of the area west of
Naples known as the Campi Flegrei or Phlegraean Fields, from the
Greek word for burning, are a major tourist attraction.
But the zone of intense seismic activity, which the ancients
thought was the entrance to hell, also could pose a danger of global
proportions with millions of people literally living on top of a
potential future volcanic eruption.
"These areas can give rise to the only eruptions that can
have global catastrophic effects comparable to major meteorite
impacts," said Giuseppe De Natale, head of a project to drill
deep under the earth to monitor the molten "caldera".
One such meteorite impact is thought to have caused the extinction
of the dinosaurs 65 million years ago when debris thrown into the
atmosphere from the huge explosion plunged the earth into darkness.
Scientists plan to drill 3.5 km (2.2 miles) below the surface to
monitor the huge chamber of molten rock near Pompeii and give early
warning of any eruption from a 13-km-wide collapsed volcanic caldera.
The Campi Flegrei are similar 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.
"Fortunately, it is extremely rare for these areas to erupt
at their full capacity, as it is extremely rare for large meteorites
to hit the earth," De Natale told Reuters.
"But some of these areas, in particular the Campi Flegrei,
are densely populated and therefore even small eruptions, which are
the most probable, fortunately, can pose risks for the population,"
said De Natale, from the Vesuvius observatory at Italy's National
Institute for Geophysics and Volcanology.
"That is why the Campi Flegrei absolutely must be studied and
monitored. I wouldn't say like others, but much more than the others
exactly because of the danger given that millions of people live in
the volcano."
However, the project, funded by the multi-national International
Continental Scientific Drilling Programme, 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.
"There were dozens of drillings in the past, with much less
secure instruments for industrial motives and nobody said anything,"
he said.
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.
"Some of the things they suggested are laughable," he
said, adding that the project's priority will be scientific knowledge
and safety of the local population rather than industrial
exploitation as in the past.
"We believe the security of millions of people deserves the
most powerful methods of inquiry without thinking too much about the
economic aspect," 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 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.
"This will increase by a thousand or 10,000 times our ability
to detect small episodes that are precursors of future eruptions,"
he said.
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
surface because of deep volcanic activity. This is episodic but in
the latest phase the ground has risen by 3.5 m (yards) 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 harbor 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 C (930 F). 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 fiber optic sensors able to withstand
the extreme heat that would have destroyed earlier electronic
equipment.
"We will be able to identify the smallest signs of a future
eruption...this is an enormous mitigation of the volcanic risk,"
he said.
De Natale says there will be no risk of an escape of magma because
the molten chamber is at 7-km depth or lower and sensors will give
ample warning of temperatures that reach 1,000 degrees C at the
molten core.
"We will stop everything if we detect temperatures at 500
degrees...we can close the top of the drilling hole hermetically in a
fraction of a second," he said.
"There is a risk that the drilling can lead to a shift of the
earth's surface and if that happened, rather than helping to predict
future problems, they will be creating them," Pozzuoli student
Marco Laporta said.
Many are more sanguine. "Back in the 1980s they said we would
all be blown up and we weren't," pensioner Luigi Bruni said.
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