Natural Hazards and Earth System Sciences | 2019
Tsunami risk assessment for multiple buildings by consideringspatial correlation of wave height using copulas
Abstract
Abstract. It is necessary to consider simultaneous damage to multiple buildings when performing probabilistic risk assessment for a portfolio of buildings. In this study, we demonstrate tsunami risk assessment for two buildings using copulas of tsunami hazards that consider the nonlinear spatial correlation of tsunami wave heights. First, we simulated the wave heights considering uncertainty by varying the slip amount and fault depths. The frequency distributions of the wave heights were evaluated via the response surface method. Based on the distributions and numerically simulated wave heights, we estimated the optimal copula via maximum likelihood estimation. Subsequently, we evaluated the simultaneous distributions of the wave heights and the aggregate damage probabilities via the marginal distributions and the estimated copulas. As a result, the aggregate damage probability of the ninety-ninth percentile value was approximately 1.0\u2009% higher and the maximum value was approximately 3.0\u2009% higher while considering the wave height correlation. We clearly showed that the usefulness of copula modeling considering the wave height correlation in evaluating risk of building portfolio. We only demonstrated the evaluation method for two buildings, but the effect of the wave height correlation on the results is expected to increase if more points are targeted.