Benefits of site-specific hazard analysis for seismic design in New Zealand: Revisited
Abstract
This paper revisits the sentiments expressed in a 2015 paper published by the author regarding site-specific seismic hazard analysis in New Zealand (NZ) [1]. While many of the general principles expressed remain the same, the completion of the 2022 NZ National Seismic Hazard Model (NSHM), and accompanying Draft Technical Specification TS1170.5:2024 have significantly altered how such analyses are performed in NZ, and the incremental value that they can provide beyond a code-based approach. This paper identifies instances where site-specific analyses remain valuable (and where they do not), where they will likely depart from the ‘baseline’ 2022 NZ NSHM (and TS1170.5:2024) results to a practically significant degree, and past practices for seismic source and ground-motion modelling choices which are now considered unviable. Lastly, challenges for practitioners and researchers are briefly addressed in order to further advance the practice of site-specific seismic hazard analysis over the next decade.