Dr. Florent De Martin and Dr. Pierre Gehl of BRGM (French Geological Survey) are visiting DPRI. They will deliver the following lectures:

Dr. Pierre GEHL

Integration of infrastructure risk in loss scenario

Integration of infrastructure risk in loss scenario (P. Gehl)
Critical infrastructure systems such as lifeline utilities or transportation networks have been shown to play a crucial role in the context of an earthquake disaster, whether due to the failure of infrastructure support to affected built areas or the disruption of emergency functions. Therefore, within the European-funded FP7 SYNER-G project, BRGM has contributed to the development of an original approach for the probabilistic seismic risk assessment of infrastructure systems. First, the object-oriented concept of the SYNER-G approach is detailed: it provides an adequate answer to the challenge of modelling a wide range of infrastructure components in terms of physical integrity and functionality, while offering the possibility to account for interdependencies between systems (i.e., the so-called "system-of-systems"). Its modelling and simulation features are demonstrated on a virtual proof-of-concept case, where the potentially detrimental effects of infrastructure failure on total losses are investigated. Then, the interaction between the physical damage to built areas and the disruption of road networks is discussed through the example of the city of Thessaloniki (Greece). Finally, in complement to the Monte Carlo simulation of infrastructure systems adopted within SYNER-G, the treatment of uncertainties through Bayesian Networks constitutes an abstract layer, which may be used as a decision-making support tool.

Dr. Florent DE MARTIN

Lecture on: Sensitivity of earthquake ground motion with respect to uncertain parameters

Sensitivity of earthquake ground motion with respect to uncertain parameters (F. De Martin)
Physics-based three-dimensional (3D) numerical simulations are becoming more predictive and have already become essential in improving understanding of natural phenomena, such as earthquakes and tsunamis, flooding, extreme weather, and so on. High performance computing (HPC) now offers the spatial resolution finer than the data gathered in situ to build the models used by the simulations. As a consequence, better understanding the role and impact of epistemic uncertainties (linked to ignorance of the model input parameters) is now a crucial topic in exploiting numerical predictions.

This study focuses on the understanding of the variability and sensitivity of synthetic earthquake ground motions at sedimentary basin scale associated with the epistemic uncertainties of the model of seismic wave propagation. The key question at stake is the following: What is the spatiotemporal variability and sensitivity of seismograms at the surface with respect to seismological parameters? (e.g., shear wave velocity of a specific soil layer, Earth's velocity or attenuation structures, sedimentary basin geometry, etc.)

You are welcome to attend the lectures