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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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