Cybershake NZ v17.9: New Zealand simulation-based probabilistic seismic hazard analysis
This paper presents the computational workflow and preliminary results of probabilistic seismic hazard analysis (PSHA) in New Zealand based on physics-based ground motion simulations (‘Cybershake NZ’). In the current work completed to date, the Graves and Pitarka (2010, 2015) hybrid broadband ground motion simulation approach is utilized considering a transition frequency of 0.25 Hz, a detailed crustal model with a grid spacing of 0.4 km, and an empirically-calibrated local site response model. Variation in hypocentre location and slip distribution are considered to partially account for the variability in ground motion characteristics. Ruptures from the distributed seismicity model are considered in the total hazard via empirical ground motion models. Intensity measures for sample scenario ruptures and subsequently generated hazard curves are presented here. Treatment of uncertainty in the context of simulation-based PSHA is discussed. Lastly, improvements for future versions of the ongoing effort are outlined.