London Earthquakes

Experts predict a 5.5 magnitude earthquake could hit London at any time
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Britain is overdue a potentially devastating earthquake that could topple London's grandest landmarks, cause billions of pounds worth of damage and endanger scores of lives, a leading seismologist warned yesterday.
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Dr Roger Musson of the British Geological Survey in Edinburgh said that a sub-sea fault under the Straits of Dover that has caused two large earthquakes in the past 700 years could strike again at any time, putting London in the firing line.
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The geological fault has already generated relatively large earthquakes in 1382 and 1580 and there is a substantial risk that a similar-sized earthquake could occur again with severe consequences for the capital given that it rests on clay soil that is easily shaken.
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Something that has happened twice can and probably will happen three times.
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But whether it happens tomorrow, or in two years' time or in 20 years or 50 years, that is something we would love to know but we don't, he said.
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While the next earthquake would not be a disaster on an international scale, it will come as an unpleasant shock for a country that tends to think itself immune from earthquakes
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Although the British Isles does not lie on a major boundary of a tectonic plate, where most large earthquakes tend to occur, the country experiences regular small earthquakes due to a network of minor fault lines, including the one under the Straits of Dover.
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The number of quakes varies according to their size, with smaller quakes more frequent.
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Back in 1931 a 6.1 magnitude quake occurred of the coast of Yorkshire, but was powerful enough to knock the head off of a wax figure in Madame Tussauds in London.
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In 1580 two people died and many buildings were damaged due to tremors originating on the Dover Strait.
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Typically there is one earthquake of magnitude 3.5 each year, 10 earthquakes of magnitude 2.5 and one magnitude 4.5 every 10 years.
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There are a lot of little fault lines all over the place.
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It's like a dinner plate that has been broken, glued back together and squeezed, Dr Musson said
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The last large earthquake to affect London occurred on the 6 April 1580 and was estimated to have been a relatively large magnitude 5.5 based on an assessment of the area of land that was affected.
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Although the epicentre was some distance away, London was quite strongly affected, probably because the soft Thames clays are more susceptible to being shaken.
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It felled half a dozen chimney stacks and a pinnacle on Westminster Abbey.
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Two children were killed by falling stonework from Christ Church's hospital.
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The earthquake caused damage to the tower of St Peter's Church in Broadstairs, Kent, that can still be seen today, and was a virtual repeat of an earlier earthquake in 1382, caused by the same Dover Straits fault line.
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Earthquakes can and will most certainly happen again as they do every day in some part of the world 
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This is as true in Britain as anywhere else in the world.
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London has about 40 times the population that it had in the 16th Century and the older infrastructure may be as vulnerable as it was four centuries ago.
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The same earthquake tomorrow will impact far more people than in 1580.
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It would certainly be a nasty shock in terms of Britain's experience of earthquakes
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Most modern buildings would be unaffected by such an earthquake but many of the older buildings, especially those in a bad state of repair, could suffer substantial damage, especially to their chimney stacks.
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It may not sound very dramatic compared to buildings collapsing, but if people are walking in the street and a chimney falls on them, that's bad news for anyone.
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Dr Musson added that as he works for a government-funded agency, the authorities are well aware of his assessment of the risk.
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They know about it, but the public have not been told of any plans
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Nor have the public been told of the best action to take in such a situation
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Indeed the public are often the first to experience disasters and only later told of any plans that might have existed
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Steve Connor