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The amount of disaster waste is one of the most important performance indicators in quantifying the resilience of a community. In fact, disaster waste can have significant negative impacts on the environment in affected regions and hinder the postdisaster recovery process. Appropriate disaster waste management should be developed in Japan before the occurrence of the Nankai Trough earthquake. It is expected that the seismic and tsunami intensities caused by the anticipated Nankai Trough earthquake will be substantially larger than those caused by the 2011 Great East Japan earthquake. In this paper, a risk-based methodology is presented for estimating the amount of disaster waste generated by both the ground motions and the tsunami due to the anticipated Nankai Trough earthquake. First, Monte Carlo simulation-based probabilistic hazard analyses are performed to obtain seismic and tsunami hazard curves considering the uncertainty associated with fault movement along the Nankai Trough. Structural damage data associated with past earthquakes are used to develop seismic and tsunami fragility curves. The amount of disaster waste generated from a single structure is defined as the generation unit and is determined based on past disasters. Finally, with the aid of a geographic information system, the risk of disaster waste can be estimated using the hazard and fragility curves and the generation units. As an illustrative example, the risk curves and expected values associated with disaster waste in Mie Prefecture, Japan, are estimated based on the proposed framework.

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.

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