Predicting earthquakes
By Wendy Barnaby
If there is a really big earthquake in Britain, it will be on the continental slope to the north-west of the Outer Hebrides, predicted Dr Roger Musson at the British Science Festival yesterday.
There may already have been an earthquake there. In 1508, one was described as affecting all of Scotland, England and further afield in Ireland and Europe.
"Earthquakes that have happened in the past can happen again, and frequently do. So by looking at historical earthquakes we can learn something about things that are likely to happen in the future," he said.
The Haiti earthquake should not have come as a surprise, said Musson, from the British Geological Survey. Seismologists knew that an earthquake like it was possible because it had happened before - in 1770. But, apart from seismologists, nobody knew about it.
This is just as true in Britain as in other parts of the world.
On 6 April 1580 there was an earthquake whose epicentre was in the Dover Straights. It had a magnitude of 5.5 and caused extensive damage in the south-east of England and north-eastern France. Two people were killed in London and an unknown number in France.
"This could certainly happen again," said Musson, "because it was a repeat of an even earlier one, in 1382, which had almost the same epicentre, size and results."
Data bases
An online data base of all historical earthquakes in Europe - the Archive of Historical Earthquake Data or AHEAD - has been completed this year.
It allows anyone concerned with risk to find all available information on all major earthquakes in Europe.
An initiative started last year (GEM: Global Earthquake Model) aims to give the database global reach. It will enable anyone to see what has happened in the past and what might be expected in future.
Radar
Radar measurements which form an interferogram can produce a map of the ground before and after the earthquake. This enables scientists to produce a map of how the ground moved. From that, they can infer where the fault is located and what the movement was on the fault.
In the 2010 Haiti earthquake, the interferogram shows that the fault goes south of Port-au-Prince. However, there was no quake immediately south of the city, so there's another earthquake there waiting to happen.
Prediction
Scientists still cannot predict exactly when an earthquake will happen or how strong it will be.
The best preparation is to educate the population, build in the expectation of quakes, and make sure building codes are enforced.
In England, the buildings most at risk are Victorian ones in poor repair - especially chimney pots. Modern office buildings, however, won't be affected. "If you work in the gerkhin then you're going to be safe," said Dr Musson.
Dr Ted Nield, Editor of The Geoscientist magazine, said: "The rocks of Britain are livelier than we think. Earthquakes are not just something that happen in California, and we need to be prepared."
If there is a really big earthquake in Britain, it will be on the continental slope to the north-west of the Outer Hebrides, predicted Dr Roger Musson at the British Science Festival yesterday.
There may already have been an earthquake there. In 1508, one was described as affecting all of Scotland, England and further afield in Ireland and Europe.
"Earthquakes that have happened in the past can happen again, and frequently do. So by looking at historical earthquakes we can learn something about things that are likely to happen in the future," he said.
The Haiti earthquake should not have come as a surprise, said Musson, from the British Geological Survey. Seismologists knew that an earthquake like it was possible because it had happened before - in 1770. But, apart from seismologists, nobody knew about it.
This is just as true in Britain as in other parts of the world.
On 6 April 1580 there was an earthquake whose epicentre was in the Dover Straights. It had a magnitude of 5.5 and caused extensive damage in the south-east of England and north-eastern France. Two people were killed in London and an unknown number in France.
"This could certainly happen again," said Musson, "because it was a repeat of an even earlier one, in 1382, which had almost the same epicentre, size and results."
Data bases
An online data base of all historical earthquakes in Europe - the Archive of Historical Earthquake Data or AHEAD - has been completed this year.
It allows anyone concerned with risk to find all available information on all major earthquakes in Europe.
An initiative started last year (GEM: Global Earthquake Model) aims to give the database global reach. It will enable anyone to see what has happened in the past and what might be expected in future.
Radar
Radar measurements which form an interferogram can produce a map of the ground before and after the earthquake. This enables scientists to produce a map of how the ground moved. From that, they can infer where the fault is located and what the movement was on the fault.
In the 2010 Haiti earthquake, the interferogram shows that the fault goes south of Port-au-Prince. However, there was no quake immediately south of the city, so there's another earthquake there waiting to happen.
Prediction
Scientists still cannot predict exactly when an earthquake will happen or how strong it will be.
The best preparation is to educate the population, build in the expectation of quakes, and make sure building codes are enforced.
In England, the buildings most at risk are Victorian ones in poor repair - especially chimney pots. Modern office buildings, however, won't be affected. "If you work in the gerkhin then you're going to be safe," said Dr Musson.
Dr Ted Nield, Editor of The Geoscientist magazine, said: "The rocks of Britain are livelier than we think. Earthquakes are not just something that happen in California, and we need to be prepared."
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