On July 6, 2019, as every year, a crowd was crowded in front of the Pamplonese town hall. None of the nearly 5,000 people present at the beginning of the San Fermín festivities knew that their presence and movements during the science was going to be transformed into science.
A wave of people. Specifically, in the study that has revealed that human agglomerations are governed by the same laws that operate in fluid physics, at least from a certain degree of population density.
The rebellion of the masses. In a study that could have delighted the philosopher José Ortega y Gasset, studying the filling of the square in the minutes before the chupinazo, the team detected the threshold from which the movements of the individuals in the square ceased to be unpredictable and began to operate according to physical laws such as those governing fluid physics.
The team studied the movements before the agglomeration, when the density of people in the square of just over 600 square meters is around the two people per m², until reaching 9 people per m² in the moments of greater agglomeration. The team observed that the change in the dynamics occurred from the four people for m², when the contact between a person and those around them causes the clashes and shoves to become inevitable. It is at that time that the movement of one becomes the movement of many.
In bird view. The study used images and videos compiled by the surveillance cameras located in the Pamplonesa Consistorial Square during the Chupinazos of 2019, 2022, 2023 and 2024. The details about the study process and its results have been published recently in an article in the magazine in the magazine Nature.
Oscuring mass. Through these images, the team was able to detect periodic oscillations of 18 seconds in the attendees. Oscillations that led to small groups of people to draw circular movements that dragged with them increasing groups of people.
“Being inside the town hall square during the chupinazo (…) is a unique experience. It is the closest thing to being a tiny particle trapped in a dense, chaotic and constant movement space, with the notable difference that the rest of ‘particles’ carry red scarves and, probably, have lunch with more wine than recommended, ”he describes for SMC Spain Iñaki Echeverría Huarte, a professor in the Department of Physics and Mathematics applied to the Faculty of Sciences of the University of Navarra, partner of one of the authors but not involved in the study.
More than leisure. Understanding the dynamics we acquire in agglomerations is not just a curiosity, it can help us save lives. The examples in which a tide of people has ended up being charged in mass events are countless.
The team observed that the chiral dynamics observed in the Sanferminera massification were similar to those that operated in the tragedy of the 2010 Love Parade in Duisburg, to the west of Germany. On that occasion 21 people lost their lives and hundreds were injured.
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Image | Travel24h
