In a paper for the Journal of Maps published in 2014 I have analysed and visualised data documenting earthquakes that have occurred since 2150 BC. The following map was part of the material supplementing the publication showing the results of the analysis shown on an equal population projection. The gridded cartogram gives every person on the planet an equal amount of space while highlighting the most densely populated spaces in relation to the earthquake risk (calculated via the intensity of earthquakes recorded since 2150 BC). Also shown are the world’s megacities (over 5 million population). The map shows the large populations that make even Nepal (with its almost 28 million people) much more visible than it would be on a conventional map, highlighting why this event turns out to be quite disastrous. The map also shows what the USGS statement above mentions that Nepal is amongst the areas in the region which are far less subject to major earthquakes (as indicated by the yellow to blue shading in the map there):

(click for larger version)
Download as poster (PDF, 62MB)

More detail about the data and the visualisation technique can be found in my paper. Here is the abstract giving a brief overview of the work: The assessment of natural events that can turn into disasters where people live is usually accompanied by maps visualising the specific topic in its spatial setting and putting the physical environment into the main focus. Such conventional mapping approaches, however, can often fail to give an intuitive understanding of the underlying quantitative dimension of the associated risk to people and a fuller appreciation of the interrelation between humans and their natural environment. The method presented here demonstrates an alternative way of mapping environmental risk. A gridded cartogram approach is introduced and illustrated with examples drawn from data documenting globally significant earthquakes that have occurred since 2150 BC. Gridded cartograms are a new map projection. They are created by starting with an equally distributed grid onto which a density-equalising cartogram technique is applied. Each individual grid cell is resized according to specific quantitative information. The underlying grid ensures the preservation of an accurate geographic reference to the real world. It allows gridded cartograms to be used as basemaps, new projections, onto which other information can be mapped. Earthquake intensity on a gridded population cartogram highlights those zones where most people live in these risk environments and minimises information about where earthquakes still occur, but where they matter less for human populations.

Find the full paper in the Journal of Maps or download the map poster here:

• Poster “Mapping People at Risk” (PDF, 62MB)
• Hennig, B. D. (2014). Gridded cartograms as a method for visualising earthquake risk at the global scale. Journal of Maps, 10 (2), 186-194.

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