Earthquake risk assessment models have ignored structural deterioration and regional infrastructure growth over time. The risk is dynamic and has to consider the time dependence of large earthquake occurrences, structural deterioration, seismic design code changes, and increase in building stock over time. A time-dependent earthquake risk model is developed by our research team that considers the problem of increasing vulnerability of structures due to corrosion and contributions to the risk by various environmental factors. Key time dependent risk components include the earthquake hazard rate, the probability distribution of structural capacity given the earthquake demand and the decision variable dependence on monetary discount rates. Life-cycle cost analysis is used to evaluate the contribution of different repair components after every damaging earthquake event. Components in the life-cycle impact analysis include estimation of greenhouse gas potential, ozone depletion potential, acidification potential and several others. Results from applications of the methodology to a single reinforced concrete bridge column show that structural deterioration does contribute to the risk over time and if ignored can result in underestimation of that risk. Moreover, the risk significantly decreases with improved seismic design. Similarly, the contribution of various life-cycle impacts is most pronounced for older structures that have greater potential for deterioration. | 
