Sonia Chardonnel

Risk perception and social vulnerability to earthquakes in Grenoble (French Alps)

The city of Grenoble (French Alps) is characterized by a rather low seismicity as well as a tectonic context prone to the occurrence of major earthquakes (M = 6). The population is therefore not used to experiencing earthquakes: this can lead to a low culture of risk, which may imply a rather high vulnerability of the population. Consequently, it is necessary to better evaluate vulnerability and to find ways of reducing it. Social vulnerability is usually evaluated through surveys focusing on residential population. When these studies are carried out by geographers, they sometimes take into account a spatial dimension by mapping the results. Here, a temporal dimension is also integrated and residents as well as users of the city, i.e. users with any activity as working, shopping, having leisure time, etc. are surveyed. The method consists in building a social and spatial representative sample through three dimensions: social (age), temporal (hour of the day) and spatial (place of residence or activity). For this reason the household travel survey was used to build the sample. The risk perception survey shows that only 16% of the sample feel exposed to earthquakes. The youngest, most qualified, the students and working people seem to better know the adequate safety measures to be taken in case of an earthquake. Besides classic statistical analyses, the answers to the questionnaire were synthesized into a vulnerability index. Once more, the most qualified are characterized by a lower vulnerability. The cartography of the survey results provides interesting conclusions for authorities in charge of risk mitigation, who could then concentrate their preventive information campaign on certain districts or social groups. Among other conclusions, these maps highlight the gap between the physical vulnerability of buildings and the confidence of the population in their resistance in case of an earthquake.

Exploring Intra-Urban Accessibility and Impacts of Pollution Policies with an Agent-Based Simulation Platform: GaMiroD

In this work we address the issue of sustainable cities by focusing on one of their very central components: daily mobility. Indeed, if cities can be interpreted as spatial organizations allowing social interactions, the number of daily movements needed to reach this goal is continuously increasing. Therefore, improving urban accessibility merely results in increasing traffic and its negative externalities (congestion, accidents, pollution, noise, etc.), while eventually reducing the quality of life of people in the city. This is why several urban-transport policies are implemented in order to reduce individual mobility impacts while maintaining equitable access to the city. This challenge is however non-trivial and therefore we propose to investigate this issue from the complex systems point of view. The real spatial-temporal urban accessibility of citizens cannot be approximated just by focusing on space and implies taking into account the space-time activity patterns of individuals, in a more dynamic way. Thus, given the importance of local interactions in such a perspective, an agent based approach seems to be a relevant solution. This kind of individual based and “interactionist” approach allows us to explore the possible impact of individual behaviors on the overall dynamics of the city but also the possible impact of global measures on individual behaviors. In this paper, we give an overview of the Miro Project and then focus on the GaMiroD model design from real data analysis to model exploration tuned by transportation-oriented scenarios. Among them, we start with the the impact of a LEZ (Low Emission Zone) in the city center.