Life-cycle risk assessment of building portfolios subjected to tsunamis under non-stationary sea-level rise based on a compound renewal process

The immense impacts of tsunamis can inflict substantial damage on coastal infrastructure systems during their lifetime and lead to considerable economic loss. However, with the increasing intensity and variability of sea-level rise due to climate change, evaluations of the life-cycle tsunami risk associated with cumulative loss have become increasingly complex since tsunami hazards are time-dependent. In addition, the number of earthquake events and the corresponding arrival times are substantially uncertain. Therefore, an accurate life-cycle tsunami risk assessment methodology should be established to appropriately develop disaster mitigation measures. This paper provides a novel life-cycle risk assessment of building portfolios subjected to tsunami hazards under non-stationary sea-level rise effects due to climate change. The cumulative loss of a building portfolio is evaluated through a compound renewal process based on earthquake interarrival time uncertainties and time-dependent risk. The earthquake interarrival times are modeled using a non-Poisson process based on historical data. Tsunami hazard curves that consider the effects of sea-level rise, estimated based on climate models, are obtained with tsunami propagation analysis. The time-variant annual risk is estimated based on reliability and building unit loss. Finally, a numerical procedure is proposed to estimate the life-cycle tsunami risk of building portfolios. An illustrative example is provided by applying the framework to several municipalities in the Kochi Prefecture of Japan to assess the effects of climate change on the life-cycle tsunami risk.