URBAn SeISmology: seismic vulnerability and damage assessment using innovative techniques – URBASIS

Increasing populations in more and more wide urban areas, made of heterogeneous buildings and exposed to earthquakes, are the ingredients that place urban area among the most critical elements of seismic risk. Their knowledge become then a key information to mitigate, predict and assess its vulnerability and post-seismic integrity. The variability of the response of a structure to earthquakes introduces an uncertainty in the assessment of its vulnerability but also in the estimation of damages. Often two scales of space (city or building) and three scales of time (before, during and after the earthquake) are invoked during the seismic assessment in urban areas. We propose to develop methods for assessing vulnerability and seismic damage throughout the city. Based on the use of remote data (aerial or satellite images), analysis of urban patterns will be done, integrating key structural parameters (height, shape, roof, etc.) for vulnerability assessment. The detection of changes before and after earthquakes will also be quantified in relation with observed damage. We also plan to develop tools for damage assessement at local scale, i.e. a structure, and based on evaluating its modal parameters (frequency, damping and modal shapes). Technological and algorithmic signal processing developments will be done to estimate its modal parameters for normal periods (inter-seismic), their variations during (co-seismic) and after (post-seismic) the shake, for evaluating the structural integrity. Finally a tool will be developped in order to show the vulnerability and damage in the city, that will facilitate the management and mitigation of the seismic crisis.