- Disaster planners say a repeat of the 1755 Great Lisbon quake is overdue
- Such a quake would wipe out Scillies and much of the coast of Cornwall
- Devon and Cornwall Local Resilience Forum wants warning system for UK
- Their concerns will be examined by government scientists and experts
By Harriet Arkell
PUBLISHED: 16 July 2013
A massive earthquake off Portugal could trigger a tsunami which would wipe out the Isles of Scilly and lay waste to the Cornish coast, scientists said today.
Experts say that much of the south-western British coast including outlying islands would be destroyed by a 10ft wall of water within four to six hours if there were to be a repeat of the Great Lisbon Earthquake of 1755.
Fears of the natural disaster have been raised by the Devon and Cornwall Local Resilience Forum (LRF), which wants an early warning system like those used across Asia and America to avoid a British version of the devastating 2004 Boxing Day tsunami.
The Isles of Scilly, which include Tresco, pictured, lie 45 miles off the coast of Cornwall, coulde be wiped out by a tsunami if Portugal suffered another devastating earthquake
LRF coordinator for Devon, Cornwall and the Isles of Scilly, Neil Hamlyn, whose job is to assess risks and then prepare for them, says catastrophic weather tends to be cyclical and said a repeat of the 1755 quake was 'overdue'.
His concerns are now being escalated and will be examined by agencies including Defra, the British Geological Society and the Met Office, with a view to a contingency plan being drawn up if deemed necessary.
Mr Hamlyn told a meeting of scientists, academics, Met Office chiefs and government officals: 'The Isles of Scilly could be affected greatly: they could be covered and disappear.
'We would have to get a lot of people off the beaches and need to know how we do it - we might have to evacuate people much further inland with rest shelters.'
He said that the primary job was assessing the likelihood of such a seismic event, and added: 'We think more work needs to be done here but we don't want to spend a lot of time on something if it is not going to happen.'
But he told MailOnline: 'As we started looking at the risk it became quite clear that as we haven't had an earthquake for a couple of centuries, the expectation is that we are overdue.'
St Martin's is one of the five inhabited Isles of Scilly - plus dozens of islets - with a total population of around 2,100
Paul Netherton, assistant chief constable of Devon and Cornwall Police and LRF chairman, said other countries had suffered by failing to plan ahead.
He said: 'There has not been a tsunami for more than 250 years and hopefully we won't see one for another 250.
'But after seeing the devastation in Japan and Thailand we have to ask the question of the scientific community - what and where would be the impact, is it likely and, if it is, should we plan for it?'
The meeting in Bristol heard that Britain was last hit by a tsunami in 1755, the year of the Great Lisbon Earthquake, four hours after the Portuguese city was rocked by the quake which had a magnitude of around 8.5-9.0.
Mr Netherton said: 'A lot of areas would cope, but in others it would cause a big problem. We have to consider whether we do anything differently than we do now for severe weather events.
'Tsunamis are different - you don't know they are coming and the water keeps coming and coming.'
Other parts of Europe, including France, Spain and Portugal, have undertaken large scientific studies to model the effect of a tsunami.
Quake zone: Lisbon was ripped open by the 1755 earthquake which left fissures 15 feet wide in the city centre
The United States and Canada are among countries who have initiated early warning systems but the UK has no buoys which could detect a sudden surge of water.
In the event of an earthquake in the Atlantic, the public would currently rely on the British Geological Survey to register the quake and the arrival of a wave at nearby Portugal.
If a wave was to suddenly build in midsummer, leaving just a few hours warning, emergency services would struggle to deal with beaches full of holidaymakers.
'Four hours sounds quite a long time but in summer our population rises to 8m people and most of them are on the beach.'
- Neil Hamlyn, LRF coordinator for Devon, Cornwall and the Isles of Scilly
Mr Hamlyn said: 'Four hours sounds quite a long time but our region has a population of 1.5m ordinarily which in summer that rises to 8m people, most of whom are on the beach.'
Under the Civil Contingencies Act of 2004, the UK maintains a National Risk Register of Civil Emergencies.
The very high risk table is currently topped by pandemic flu, terrorist attacks and coastal flooding, though the last major civil flooding emergency was on the east coast in 1953.
Mr Hamlyn says a tsunami is in the top 20 of the second category of high risks.
Other uniquely regional threats include a nuclear submarine incident at Devonport dockyard and possible contamination from old tin mines in Cornwall.
Work has also already been done to predict the catastrophic impact should a massive slab of rock twice the volume of the Isle of Man break away from the island of La Palma, in the Canary Islands, and smash into the Atlantic Ocean.
The resulting tsunami, higher than Nelson's Column and faster than a jet aircraft, would devastate the eastern seaboard of America and inundate much of southern Britain.
THE GREAT LISBON EARTHQUAKE - ONE OF THE DEADLIEST IN HISTORY
The 1755 Lisbon earthquake, also known as the Great Lisbon Earthquake, occurred on Saturday, November 1, 1755.
The earthquake, which had its epicentre around 200 miles south-west of Cape St Vincent on the Portuguese coast, almost totally destroyed Lisbon and had a magnitude in the range of 8.5 on the Richter scale.
It struck in the morning and lasted between three and six minutes, leaving vast cracks 15ft wide in the city centre streets.
An engraving by Laplante from Le Monde Illustre shows how Lisbon was destroyed in the earthquake of 1755
Around 40 minutes later, a vast tsunami engulfed the city's docks and centre, followed by two more waves.
Estimates place the death toll in Lisbon alone between 10,000 and 100,000 people, making it one of the deadliest earthquakes in history.
But its devastating impact was not only felt in Portugal - it travelled more than a 1,000 miles before crashing into the British Isles.
At around 2pm on the same day, a wave reported to be between three to four metres in height hit the shores of Cornwall, smashing into Mount's Bay, the area's highest point, where it killed at least one person.
Estimates suggest that the death toll in Lisbon reached between 10,000 and 100,000 people, making it one of the deadliest earthquakes in history
The waves (there were two more) also struck the south coast and were even seen in the River Thames in London.
The tsunami even reached as far as Galway in Ireland, where it was described as being two metres high.
French writer Arnold Boscowitz claimed the wave caused a 'great loss of life and property occurred upon the coasts of Cornwall'.
Recent studies show that should another earthquake of the same magnitude happen, it could affect the south west of England.
A wave would take approximately five hours to travel to Britain, with maximum water heights reaching one to two metres around the vast coast of Cornwall.
But it would peak at around four metres (13ft) in Mount's Bay.
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