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This article is part of the Com2SiCa research, which seeks two objectives: firstly, to understand the diversity of human behavior and the way in which it can evolve during a major, sudden and unpredictable disaster; and, secondly, to analyze the trajectories associated with spontaneous decisions to evacuate (or not) the area where a disaster has occurred.Knowledge in this field is scarce because of the difficulty, for both practical and ethical reasons, to address the diversity of behavioral responses during the course of a disaster. In order to capture this precise moment, “during” the event, we have developed an experimental field survey methodology that relies on an immersive visual and acoustic simulation. By immersing participants in disaster scenarios, this innovative method aims to produce data on observable behavioral responses to emergency situations. Trialed in two coastal cities, Nice and Le Havre, in order to test the replicability of the approach and compare the results, it was designed for "natural" or "industrial" disaster scenarios with common temporal characteristics, that is, a sudden, rapid onset with little or no warning. We present the approach, its goals and the type of methodological innovation it entailed. The city of Le Havre was chosen as a case-study to test our method. Our results highlight the validity and value of conducting immersive field investigations and confirm the fact that, for the same disaster scenario, people can behave in a wide variety of ways, and may be alert, in control or in a state of panic. Some people are static (for example, immobile or stunned), while others are dynamic (for example, searching for loved ones or fleeing). The result of this behavioural diversity is a heterogeneity in the trajectories taken to evacuate the site of the disaster or to take cover. We also observe that trajectories depend on the spatial configuration of the location where the event takes place. Knowledge of this behavioural heterogeneity as well as the influence of location could be useful to decision-makers and other stakeholders.

La prevención del riesgo de desastre se ha convertido en los últimos 30 años en un desafío social de gran relevancia en los países desarrollados, debido principalmente al aumento de las pérdidas financieras, la distribución desigual de las pérdidas humanas a escala planetaria y una mediatización "catastrófica" de cualquier evento. Para reducir la vulnerabilidad que se ve enfrentada la población y los territorios, es posible apuntar a 3 ejes: Políticas de planificación, ingeniería civil y la capacitación a la población para adaptar sus comportamientos frente a una situación de desastre. Este artículo se centra en esta último, en efecto, es posible identificar comportamientos específicos de estas situaciones excepcionales gracias a investigaciones en Ciencias Sociales y Humanas. La mayoría de los casos, estos aportes se enfocan sobre la observación de las reacciones humanas que se producen posterior a un evento específico o analizan comportamientos típicos como saqueos o pánico. No es común que las investigaciones consideren el avance del conocimiento en neurociencia el cual señala que posterior a un shock, los seres humanos pocas veces desarrollan solo un tipo de comportamiento; más bien, se está en presencia de una cadena de reacciones conductuales. Los primeros, instintivos y de corta duración, dan paso a reacciones razonadas según las regiones del cerebro que procesan la información. Es en tal marco, esta investigación multidisciplinar reúne a geógrafos, matemáticos e informáticos y presenta el panel de comportamientos humanos que pueden ocurrir posterior a un desastre y organizamos este conocimiento en forma de tipología. Este se estructura en dos ejes: las áreas cerebrales implicadas en las respuestas conductuales y las fases temporales del desastre. En apoyo de esta tipología, proponemos un modelo matemático que permite comprender estas reacciones individuales y colectivas en forma de secuencias de comportamiento y estudiar su modo de propagación. Se modelizan mediante ecuaciones diferenciales tres tipos de reacciones (denominados respectivamente: comportamiento reflejo, comportamiento de pánico y comportamiento controlado) y sus interacciones.

Over the last thirty years, the prevention of risks and disasters has become a major issue for societies in developed countries. These concerns are linked with important financial losses, the unequal repartition of global casualties and a wide media coverage of all catastrophic events. Our societies, independently of their development level, are not well prepared to cope with natural or anthropogenic disasters and possible domino effects. In order to reduce the vulnerability of populations and territories, three levers can be used: planning policies, civil engineering and training in order to adapt their behaviors to disaster situations. This paper deals with this latter lever. Indeed, specific behaviors in these unexpected situations have been observed by researchers in Human and Social Sciences from different disciplines, such as the medicine of catastrophes, psychology, sociology, anthropology and geography. Most of the time, this research deals with the observation of human reactions during a specific event or with the analysis of specific behavior such as looting or panic. These works rarely take into account the progress of knowledge in neurosciences, which teaches us that, during a crisis, people rarely adopt a unique behavior; rather there is a sequence of behavioral responses. The first, instinctive and of short duration, gives way to reasoned reactions according to the brain areas processing the information. Thus, in this multidisciplinary research including geographers, mathematicians and computer scientists, we present the panel of human reactions that may occur during catastrophic events and we organize this knowledge around a typology. This typology is structured around two axes: the areas of the brain involved in behavioral responses and the temporal phases of the disaster. Based on this typology, we propose a mathematical model in order to understand these individual and collective responses as behavioral sequences and to study their propagation. Three types of reactions (reflex behavior, panic and controlled behavior) and their interactions have been modelled by a system of differential equations.