A global probabilistic tsunami hazard assessment

Large tsunami occur infrequently but have the capacity to cause enormous numbers of casualties, damages to the built environment, critical infrastructure, and economic losses. A sound understanding of tsunami hazard is required to underpin management of these risks, and while tsunami hazard assessments are typically conducted at regional or local scales, globally consistent assessments are required to support international disaster risk reduction eorts. This study presents a global scale probabilistic tsunami hazard assessment (PTHA), extending previous global scale assessments based largely on scenario analysis. Only earth- quake sources are considered, representing about 80% of damaging tsunami events. Globally extensive estimates of tsunami runup height are derived at various exceedance rates, and the associated uncertainties are quantied. Epistemic uncertainties in the exceedance rates of large earthquakes often lead to large uncertainties in the tsunami runup. Deviations be- tween the modelled tsunami runup and event observations are quantied, and found to be larger than suggested in previous studies. Accounting for these deviations in the PTHA is important, as it leads to a strong increase in predicted tsunami runup for a given exceedance rate.