A Hybrid Time-Dependent Probabilistic Seismic-Hazard Model for Canterbury, New Zealand

We developed a hybrid time-dependent seismic-hazard model for application to the recovery of Canterbury, New Zealand, following the Canterbury earthquake sequence. We combined earthquake-clustering models of three timescales (short-term, medium-term, and long-term) to develop a model that accounts for the significant epistemic uncertainty in the earthquake rates. For the probabilistic seismic-hazard calculations, these models were coupled with two ground-motion prediction equations. The weights for the construction of the hybrid model and for the logic tree were obtained using a structured expert elicitation process. Forecasts from the model have been used to provide earthquake probabilities to a range of end users on timescales from 1 day to 50 years. Additionally, the 50-year hazard forecast has been used in the revision of the New Zealand building design guidelines and other aspects of the reconstruction of Christchurch.