Jean-Pierre Nadal, CNRS, Laboratoire de Physique Statistique, ENS, and Centre d’Analyse et de Mathématique Sociales, EHESS, France
During autumn 2005, after two youth died while trying to escape a police patrol, riots started in a poor suburb of Paris, spread around and then in all France, hitting more than 800 municipalities and lasting about 3 weeks. Remarkably, although there were no displacements of rioters, the riot activity did travel. Thanks to an access to daily national police data, we analyzed the dynamics of riot propagation.
In this talk I will show that a parsimonious data-driven epidemic-like model, taking into account both local (within city) and non-local (through geographic proximity or media) contagion, allows reproducing the full (day by day) time course of the riots at the scale of the country. I will make explicit the specificity of the model as compared to the modeling of the spread of infectious diseases.
Moreover, I will show that our analysis allows to give a precise mathematical characterization to the expression “wave of riots”, and to provide a visualization of the propagation around Paris, exhibiting the wave in a way not described before. The remarkable agreement between model and data demonstrates that geographic proximity played a major role in the propagation, even though information was readily available everywhere through media.
This work is the result of a multidisciplinary collaboration involving expertise in sociology, computer science, physics, and mathematics.
Ref.: Laurent Bonnasse-Gahot, Henri Berestycki, Marie-Aude Depuiset, Mirta B. Gordon, Sebastian Roché, Nancy Rodriguez & Jean-Pierre Nadal, “Epidemiological modelling of the 2005 French riots: a spreading wave and the role of contagion”, Scientific Reports 8, Article number: 107 (2018) http://rdcu.be/H801