Prof. Dirk Helbing

Chair of Sociology, in particular of Modeling and Simulation, ETHZ

November 09, 2007, 11:15, Room GC B3 424 (click here for the map)

Crowd Turbulence: The Dynamics of Crowd Disasters

<p>In the past, physicists have discovered various self-organized phenomena in pedestrian crowds such as the formation of lanes of uniform walking direction, oscillations at bottlenecks in bi-directional flows, the formation of stripes in cross-flows, or "freezing-by-heating" and "faster-is-slower" effects in panicking crowds. These phenomena have all been successfully described by driven many-particle models, as will be demonstrated by animated computer simulations and video recordings of real crowds. </p> <p> Panic stampedes are a serious concern during mass events. However, despite huge numbers of security forces and crowd control measures, hundreds of lives are lost in crowd disasters each year. A high-performance tracking analysis of unique video recordings of the Muslim pilgrimage in Mina/Makkah, Saudi Arabia, has now revealed that high-density flows can even turn "turbulent", which causes people to fall. The occuring eruptions of pressure release bear analogies with earthquakes and are de facto uncontrollable. This talk presents an analysis and interpretation of our recent discoveries and shows that the measurement of the gas-kinetic "pressure" is suitable for an advance warning of critical crowd conditions.</p>