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by Nic Outterside, Evening Chronicle
A gigantic
tidal wave, triggered by North Sea gas drilling, could wash
the region away, scientists fear.
A natural
disaster, known as a mega-Tsunami, wiped out most of the
North East 7,000 years ago and experts fear another could
happen.
The
claims could delay development of one of the North Sea's
largest gas fields.
Top
British scientists are investigating the risks of sinking
gas wells in an area of the North Sea which once triggered
a massive wave which flooded 250 miles of our coast.
Some
experts say if gas firms get exploration wrong another wave
could wipe out the entire North East, killing millions.
A British
Geographical Society spokesman said: "About 7,100 years
ago, a 30 feet high wall of water hit the North East coast.
"If
this were to recur, as scientists say it could, it would
cost tens of billions of pounds to repair the damage. And
the cost in lives could be higher."
Oil
companies Norsk Hydro and BP Norge have begun sinking exploratory
wells in the Ormen-Lange field, East of Shetland, after
estimates that it could hold a 350 billion cubic metres
of natural gas.
But
if a scientific assessment by the British Geological Survey
(BGS) shows drilling could cause another tidal wave they
will stop the oil giants' costly project in its tracks.
The
newly discovered Ormen-Lange field lies within an area of
seabed known as Storegga.
The
Storegga Slide was one of the world's largest undersea earthquakes:
4,000 cubic miles of sediment moved from an area the size
of Northumberland, Durham and Cumbria, on the seabed off
Norway.
When
the last major movement occurred in 5,100BC, the resulting
250-mile long tidal wave inundated the North East coasts
of England and Scotland, just like our montage picture of
a giant wave heading for the coast at North Tyneside.
A tidal
wave on that scale today would devastate many cities, causing
a disaster unparalleled in history.
Slides
the size of Storegga are triggered by seabed gas build-up
and explosions or undersea earthquakes of six and seven
on the Richter Scale.
The
BGS seismology unit has detected more than 35 undersea earthquakes
between four and six on the Richter scale, in the same area,
in the last 30 years.
In 1994
an offshore earthquake of 4.5 was recorded near Storegga.
Last
year two separate earthquakes shook the seabed close to
Storegga. The first measured 4.2 on the Richter Scale. Then
five hours later a 4.6 quake hit the Northern North Sea
sending shudders across nearby oilfields.
"Of
the earthquakes detected during the past 15 years these
ones in the North SeaNorwegian Sea are some of the biggest
in Western Europe," said Dave Long, a marine biologist
at BGS.
"They
are still a magnitude down from what could cause a major
slide but as they have reached the current level we are
trying to use the data to calculate when the bigger ones
will occur."
The
Richter Scale measures earthquakes by 30-fold increases:
so a force six earthquake is 30 times stronger than a force
five.
Research
by the BGS has revealed where a force four earthquake may
occur once every seven years, a force five every 70 years,
a force six every 700 years and so on. Therefore, the British
Geographical Society fears a force seven quake - enough
to trigger a major seabed slide - could be due. The frequency
of North SeaNorwegian Sea quakes was giving scientists cause
for concern even before the major gas discovery at Ormen-Lange.
Norsk
Hydro found the gas field in 1997.
If developed
it will be one of the biggest North Sea gas fields, worth
billions to the developers and Shell, who will run it if
it comes onstream.
But
it is Ormen-Lange's proximity to Storegga which is causing
concern.
BGS
scientist, Dan Evans, has acted as a consultant to BP and
Norsk Hydro over their proposed exploitation of Ormen-Lange.
His
expertise may decide the future of the field and if the
oil giants can cash in.
Dr Evans
said the Norwegian oil firms had placed a contract with
the Department of the Environment and BGS to analyse data
on the Storegga Slide
"It
is part of a risk assessment exercise," he said. "The
interpretation work has been done by Brit Survey in Great
Yarmouth. Analysis will continue before any determination
of risk can be assessed. There is a possibility that drilling
could disturb the equilibrium on the seabed," said
Dr Evans.
"If
there is any instability, even a small slide would be enough
to destroy a small structure such as a drilling rig on the
seabed. And we are aware of the dangers of a bigger slide."
A spokesman
for BP Norge admitted the future of drilling in the Ormen
Lange field was uncertain.
"Ormen-Lange
is a very significant size for Norway, but there is still
a big question mark over what may happen," the spokesman
said.
"We
are aware of the history of the Storegga Slide, and we have
to evaluate the risk involved."
He could
not confirm the length of delay the assessment may cause.
He said BP Norge was working very closely with Norsk Hydro
and BGS on what to do next.
A spokesman
for Norsk Hydro, said they hoped the risk from Storegga
would not halt their quest to drill for gas.
"We
hope to make a decision on how to go ahead next year and
put together a plan to develop the field by 2003,"
he said.
"Although
there are seabed problems we hope they won't stop our plans.
We are continuing with geotechnical borings to evaluate
the stability of the seabed.
"We
look on Storegga as a challenge - but we must get it right,"
he added.
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