Abhatoo - Centre Nationale de Documentation

Here we present an overview of concepts, ideas, and examples of extreme events (Xevents), and explore various methodological ideas for anticipating, and sometimes even forecasting, the occurrence of these rare and often socially damaging surprises. The emphasis in this paper is on Xevents in social systems, as opposed to the surprises nature throws our way like earthquakes, hurricanes and volcanic eruptions. Part of the story told here involves the creation of a taxonomy of Xevents, in order to deconstruct their investigation into classes of problems ranging from the relatively easy to address to the nearly impossible. After an exposition of general issues and considerations surrounding Xevents, the paper takes a high-level overview of three topical areas -economic/financial crashes, pandemics, cybershocks - to illustrate the general ideas. We conclude with a brief account of social unrest as Xevents, and end by listing various areas of research that appear ripe for investigation in the short-term.