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London’s overdue killer quake: a case study in media sensationalism 17 September 2010

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Earthquakes are even less amenable than volcanic eruptions to effective forecasting. Unlike volcanoes with their precursory signals, earthquakes rarely give any warning of what is about to happen. As with volcanoes, though, what has happened in the past at a particular location can offer valuable indications of what may happen in the future, so the evidence left by the earthquakes of the past is an important source of information for the earthquake scientists, civil defence authorities and town planners of today.

Which is where historians come into the picture. Significant earthquakes in populated places rarely pass unnoticed: people write about them, study them, and publish accounts of them in all kinds of ways, creating written evidence that can be used alongside other sorts of data to inform our knowledge of earthquakes in a particular area throughout history. Gathering this information together and making it available is a big job, and for the last few years Italy’s Istituto Nazionale di Geofisica e Vulcanologia (INGV) has been leading an international project involving earth scientists and historians who have been assembling an online database of historical earthquake data. The initial result is the AHEAD database (Archive of Historical EArthquake Data – not too contrived an acronym, as these things go), which brings together data on the most significant damaging earthquakes in Europe from 1000 to 1963.

Among the INGV’s partners in this project is the British Geological Survey (BGS). To accompany the launch of the AHEAD site the BGS has an article on its website by seismologist Dr Roger Musson entitled ‘Are yesterday’s earthquakes tomorrow’s disasters?’ which explains the rationale behind the project, examines the way in which increasing urbanization makes human society more vulnerable to earthquakes, and has some interesting things to say about Britain’s earthquake history. An earthquake in the Straits of Dover in 1580 of estimated magnitude 5.5, for example, caused damage in London and south-eastern England, and two people were killed. There was a similar earthquake in the same location in 1382. Dr Musson’s article ends thus:

What has happened twice can happen a third time; what will be the effects on the London of today? In 1580, two people in London were killed. Modern London has about 40 times as many people living in it and while a comparable earthquake would certainly not cause a disaster on an international scale, the level of shaking would come as an unpleasant shock in a country that tends to think of itself as immune from earthquakes.

A moderate, balanced, entirely reasonable conclusion. Dr Musson has also been speaking at the British Science Festival at Aston University: I do not have access to exactly what he said, but it would be very surprising if it was not equally evidence-based and unsensational. And this is what the media have made of Dr Musson’s statements:

Expert warns of killer ‘quake: ‘A killer earthquake could hit London at any time, claiming untold numbers of lives and causing billions of pounds worth of damage, an expert has warned. Such a quake is long overdue after the last one occurred on April 6 1580, said seismologist Dr Roger Musson.’ (Press Association)

Earthquake Britain: Expert warns long overdue tremor could kill at least 100: ‘A leading geologist warned yesterday that Britain is at risk of being hit by a lethal earthquake.’ (Daily Mirror)

London is overdue for a major earthquake, warns seismologist: ‘London is overdue for an earthquake that could cause billions of pounds worth of damage, a leading seismologist warned today.’ (The Guardian)

UK overdue an earthquake that could kill scores of people at any moment: ‘Britain is overdue a killer earthquake that could see up to 100 people crushed to death, a leading geologist has warned.’ (Daily Mail)

About time London rocked: ‘A killer earthquake in London is long overdue, a leading expert said yesterday. Seismologist Dr Roger Musson from the British Geological Survey said a major tremor would kill thousands of people and cause billions of pounds’ worth of damage.’ (The Sun)

Expert predicts 5.5 magnitude earthquake could hit London at any time: ‘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.’ (The Independent)

Killer earthquake warning issued: ‘A killer earthquake could hit London at any time, claiming untold numbers of lives and causing billions of pounds worth of damage, an expert has warned. Such a quake is long overdue after the last one occurred on April 6 1580, said seismologist Dr Roger Musson.’ (Yahoo News UK)

It’s that word ‘overdue‘ that does it. Earthquakes are not buses, they do not run to a timetable and it is meaningless (and worse, misleading) to use that loaded word ‘overdue’, with all its implications of a cataclysm hanging over us and that we are living on borrowed time. That’s the kind of thing Enzo Boschi of the INGV calls media melodrama. What Dr Musson has actually said, just to offer a quick reminder, is that past earthquake history offers an indication of future earthquake risk, that what has happened in the past is likely to happen again, although it is impossible to say when, and that London is more vulnerable to earthquakes than perhaps most people think. And from that we leap to ‘killer quakes’ that could ‘hit London at any time’, and ‘grand landmarks’ are toppling, the Mail is busy crushing ‘up to 100 people’ to death and the Sun is gleefully anticipating a death toll of ‘thousands’. And there isn’t the slightest justification for any of it.

I don’t expect anything better from the wretched Sun or the contemptible Mail, but it’s disappointing and disturbing to see the Independent and the Guardian also playing the scaremongering game. For a refreshing contrast try the BBC News article by their science reporter Jonathan Amos: Quakes ‘are an issue for London’. Congratulations to Mr Amos for filing a sober, accurate and informative piece that does not misrepresent the science, does not pander to sensationalism, and does not use the word ‘overdue’.

UPDATE 20 September 2010. Dr Roger Musson of the British Geological Survey himself has added a comment to this story below.

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Comments

1. Hypocentre - 17 September 2010

I was at Roger Musson’s talk at Aston. He did not use the word ‘overdue’.

2. admin - 17 September 2010

Thank you for that confirmation. I would have been very surprised if he had!

3. Chris Rowan - 17 September 2010

Thanks for dealing with this. I was extremely annoyed by the Guardian’s headline – extrapolating future trends from two data points is unwise at the best of times, and especially foolish when you’re considering interplate earthquakes. The most Dr. Musson can be criticised for is leaving an unintented opening for such extrapolation.

And it was certainly interesting timing, considering the interesting conversation in the INGV thread.

4. Gijs de Reijke - 17 September 2010

An exaggerated estimate of the damage a 5.5 could do to London o_ô . The 5.8 of Roermond back in 1992 caused one or two people to get a heart attack, but no further deaths or even serious injuries. Damages were kept to a level of broken off chimneys and cracks in walls. About 6 churches required extra attention, because they sustained somewhat more substantial structural damage. But that was a 5.8, and some even say it might even have been as big as 6.1 on the Richter scale. A 5.5 is a lot weaker anyway.

5. Mike Don - 19 September 2010

The journalists don’t appear to have done much homework: in 1984 there was a 5.4 under the Lleyn Peninsula in North Wales. No fatalities, apparently no (or very few) injuries, property damage as far as Liverpool and Shropshire was mostly fallen chimneys. Couple of mouse clicks to the BGS website would have done the job

6. Roger Musson - 20 September 2010

I was actually careful to avoid putting any alarmist slant on things, and was very pleased to see Jonathan Amos give such an accurate and balanced account of what I said. But if a journalist is determined to play a story up, they will. Actually, I was at a conference in France the week before the Festival of Science, and some seismologists were indeed asking, “1382 … 1580 … where’s the next one?”. A possible explanation is that sometimes earthquakes go in clusters with a long gap between clusters. The Dover Straits could be in such a gap phase. As for comparisons with Roermond, there is a confusion in magnitude scales. Roermond had, as I recall, a local magnitude of 5.8 but the moment magnitude was 5.3. So 1580 would have been a little larger.

7. Gijs de Reijke - 20 September 2010

If Roermond was indeed a 5.8, yes. Interesting. I never found any data on the moment magnitude of the Roermond earthquake, but I suppose you’re right.

The Peelrand and Feldbiss faultlines (and of course other neraby faultlines) have produced larger earthquakes in the, geologically speaking, recent past. The 6,4 quake of Düren is a nice example of that, but the area had/has(?) even bigger earthquakes, like an estimated 7 (MW I guess) around Sittard ± 200.000 years ago. Are there any records of intenser seismicity in the UK? Let’s say recent enough to not completely exclude a quake > 5.5 MW or maybe even > 6.0 MW?


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