Besides all the disturbing images in media, the devastating Japan earthquake has already been intensively documented in the world of mapping, ranging from USGS’s geophysical maps, ESRI’s Social Media mashup, and media features such as the excellent New York Times features (see here and here). More online map and imagery resources have been compiled by the editors of Directions Magazine (see here). Similar responses could already be observed during the Christchurch earthquake, which demonstrates, how fast such information is released and processed nowadays.
The following map shows a more general approach of mapping the risk of earthquakes. It is a visualisation of all major earthquakes that have been complied in the Global Significant Earthquake Database. The database created by NOAA’s National Geophysical Data Center “contains information on destructive earthquakes from 2150 B.C. to the present that meet at least one of the following criteria: Moderate damage (approximately $1 million or more), 10 or more deaths, Magnitude 7.5 or greater, Modified Mercalli Intensity X or greater, or the earthquake generated a tsunami“.
Following an approach of spatial-analyst.net, a kernel density has been calculated from these records to visualise the areas most at risk of earthquakes during that time period. In a last step, I have transformed the world earthquake intensity map (see map inset) using a density equalising cartogram algorithm applied to a population grid. Simply said, the resulting map gives each person living on earth the same amount of space while also preserving the geographical reference. This map allows to understand the earthquake intensity in relation to today’s population distribution, and thus gives an idea of where most people are of risk related to seismic activity (there is an updated version of this map showing labels for the world’s largest cities here: Megacities and Earthquake Risk).
Paying some tribute to the most recent events in Japan, here is a new population cartogram of the country which is created from a more detailed population grid than the original map from our World Population Atlas. The cartogram shows the shape a very densely populated country and helps to understand, where the majority of Japan’s population is concentrated: “80 million of the urban population is heavily concentrated on the Pacific shore of Honshū. Metropolitan Tokyo-Yokohama, with 35,000,000 people, is the world’s most populous city” (see Wikipedia). The map also includes Japan’s topography (see map inset for a conventional reference map and the surrounding bathymetry, which apparently played a crucial role in the development of the tsunami which followed the earthquake and caused much of the destruction on that densely populated Pacific shore.
Update: Another map showing the impact of the earthquake/tsunami-related power losses in the north of Japan is now available on this page: Views of the World at Night
The maps on this page have been created by Benjamin Hennig and are property of the SASI Research Group (University of Sheffield). We welcome the use of our maps under the Creative Commons conditions; please contact us for further details – we also appreciate a notification if you used our maps somewhere else. High resolution and customized maps are available on request.