Fatality risk estimation for industrialized urban areas considering multi-hazard domino effects triggered by earthquakes

The rapid expansion of the built environment has resulted in the coexistence of industrial facilities and urban centres. Following recent major earthquakes throughout the world, it has become clear that multi-hazard domino effects can significantly increase the risk of fatalities, environmental problems and losses. This complex phenomenon is not yet well understood. In this paper, the problem is treated by decomposing it into several subproblems which are described by simplified probabilistic models. These models are then coupled with the Monte Carlo method to estimate the annual probability of fatality for an individual who is continuously standing in a location of interest and to estimate fatality risk maps for an area of interest. Emphasis is placed on considering multi-hazard domino effects, which can be triggered within an industrial area due to the damage caused by earthquakes. Thus it is considered that fatalities can be caused: a) as a direct consequence of seismic damage to a unit b) as a direct physical and/or chemical consequence due to the loss of containment of hazardous material, and c) as a consequence of domino triggered by physical and chemical events such as fire, explosion, and toxic dispersion. The capabilities of the proposed methodology are demonstrated by calculating fatality risk maps for a hypothetical industrialized urban area. It is shown that disregarding multi-hazard domino effects in the estimation of fatality risk could lead to significant underestimation of the fatality risk in an industrialized urban area. Thus, it is necessary to account for multi-hazard domino effects. However, different teams of engineers can enhance the models for the probability of fatality due to various phenomena, which will improve the accuracy of the proposed methodology.