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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.


Olympus Mons and our ‘life on Mars’ obsession 5 March 2009

Posted by admin in geoscience, Mars, solar system.
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Over the past 24 hours quite a few stories have appeared in the media about a paper in the journal Geology on Olympus Mons, the giant Martian volcano. Can you spot what they have in common?

Here’s a hint: the ‘big question’ in the last headline is ‘whether the Red Planet had – or still supports – life’. Life on Mars is clearly what the Geology paper is all about.

It isn’t, of course. The paper concerned, Patrick K. McGovern & Julia K. Morgan, ‘Volcanic spreading and lateral variations in the structure of Olympus Mons, Mars’ (discussed here at The Volcanism Blog three weeks ago) is, as its title indicates, about the geology of Olympus Mons – specifically, why the volcano is the shape it is. The ‘big question’ of life gets a mention in the final paragraph.

An implication of the paper’s thesis – that Olympus Mons is underlain by clay sediments – is that there might be a reservoir of water beneath the volcano in which conditions suitable for thermophilic life might have been maintained. They only mention it in passing.

I suppose it’s understandable that Martian life is always going to have a higher media profile than Martian sedimentary geology. Is that healthy for science, though? And is there a danger that our Martian discoveries are always going to be viewed through the distorting lens of our ‘life on Mars’ obsession?

  • Patrick K. McGovern & Julia K. Morgan, ‘Volcanic spreading and lateral variations in the structure of Olympus Mons, Mars’, Geology, vol. 37, no. 2 (February 2009), pp. 139-142. [Link to abstract only]

The Volcanism Blog