More Mash-ups: Mapping A Century of Earthquakes

A recent posting on the AGU linkedin site drew my attention to a map tat plotted all magnitude 4 and above earthquakes that have occurred since 1898. The map in the Herald Sun clearly shows the distribution and the ‘hotpots’ you might expect around the Pacific ‘ring of fire’ as well as some intra-plate bursts of colour that suggest even the interior of continents are not immune from these hazards.
Although a nice image, the map represents a key trend that I mentioned in a earlier blog – mash-ups. The map was produced by John Nelson of IDV Solutions  a US software company specialising in visualising data. The maps combine data from the US Advanced National Seismic System and the United States Geological Survey to produce a map that spatially locates each piece of data. IDV Solutions understand the importance and power of such mash-ups and Deborah Davis published an article in Directions magazine (25th February 2010) on the importance of mash-ups for security. Although their observations about mash-ups are directed at security the observations in the articles are as useful for trying to understand and manage hazards and the risks associated with them.

Mash-ups provide a means of consolidating data from diverse sources into a single, comprehensible map and in a visual context that has some meaning for the observer. The map produced can be made relevant to the customer or user by ensuring that it contains additional information relevant to their interpretation of the information. A map of landslides combined with topographic data provides a context for helping to understand why the landslides might have occurred. Adding surface geology as another layer improves the context of interpretation for a landslide specialist, adding the road network improves the context of interpretation for a hazard manager. Once data has a context it is easier to spot relationships between phenomena. With this single, common map available to all parties there is a common basis for discussion and for decision-making. Having a common source of reference may even encourage discussion and debate. In addition, it may be easy to see where data is lacking and what other data these parties may require to aid their decision-making. The cost-effectiveness of such mapping should not be neglected either. Using existing data and producing a new product is very cost-efficient.

CORRECTION: BP Oil Spill: Disaster, Media Hype or Fitting a Narrative?

CORRECTION: CORRECTION: CORRECTION

I have only just noticed that because of some sloppy cutting and pasting the original blog on BP Oil Spill: Disaster, Media Hype or Fitting a Narrative? must have lost sense to the reader about halfway through (anything before that was really written like that!) Sorry about this but it is a lesson to me to read blogs through properly again and again even when you think you have already done so.

The new, edited blog is now available. The original incorrect blog has been deleted.

Environmental Geography -the key questions

Geography is often said to supply the ‘where’ bit of the set of questions ‘how, what, where and why?’ This blog views geography much as another environmental geography blogger does (http://environmentalgeography.blogspot.com/). In this blog geography asks the questions – where is it, why there and so what? This blog adds a bit more. Geography asks what is it, where is it and why there and not somewhere else and then so what? Geography looks at both the static questions of what and where as well as the more dynamic questions about why and so what. By combining these, the static and the dynamic, you get an understanding of not only what is going on but also why.

OK so in English what does that mean? Take a pollution incident. The first question is what is it? What is the pollutant? The next question is where is it? Which bit of the environment is it in and is that important? A release of sulphur dioxide from coal fires would produce a stream of gas in an urban area. Where it is important as the sulphur dioxide could affect human health if concentrations rose high enough. Likewise if a specific meteorological condition occurred, such as a blocking high pressure system, then smoke and sulphur dioxide could remain in the urban area and concentrations build up to such an extent that some people have difficulty breathing whilst others collapse and die. This is not a random example as Londoner over 60 would know. The Great Smog or Big Smoke of Friday 5th to Tuesday 9th December 1952 was the result of the interaction and coincidence of large releases of smoke and sulphur dioxide from low quality coal from power stations and domestic fires and the presence of an anticyclone over London from 4th December. The resulting temperature inversion over London effectively trapped the pollution.

Figure 1: Nelson's coloumn nearly hidden in the Great Smog

The last question is why there and not somewhere else. Pollution wasn’t uncommon in 1950s London. Low quality coal, cheap fuel in post-war Britian, had been used before; power stations were not new inventions. Likewise, anticyclones are not an unusually weather phenomenon. So the question is why there and why then? The preceding days had been cold; more coal was being burnt than usual. Diesel fumes added to the usual mix as relatively new buses took over from the recently defunct tram system. Mix in the pollution from industrial Europe that had blown across the Channel in the days before and the amount of pollution was higher than usual and not a breathe of wind to disturb the stillness of the brown shroud of pollution and all the elements come together to explain the why.

Figure 2: Carrying on inthe Great Smog

The why doesn’t necessarily stop there. You could ask why was cheap coal needed? Why was the tram network removed? Why didn’t authorities predict the dramatic health problems the smog would produce – an estimated 12,000 people in the following weeks and months, mostly young, old and people with pre-exiting respiratory problems?

Figure 3: Deaths due to the Great Smog (source for image -Wikipedia)

You could also then explore the so what question. What was the significance of the Great Smog – in other words does it matter? At a micro scale every life lost dramatically answers the so what question. The individuals are not just numbers but people who had families, jobs an existence beyond the point they became in a historic graph. At a national scale, the so what is answered by the Clean Air Acts of 1956 and 1958, a direct outcome of the havoc caused by this pollution incident.