National Seismic Hazard Model for New Zealand: 2010 Update

A team of earthquake geologists, seismologists, and engineering seismologists has collectively produced an update of the national probabilistic seismic hazard (PSH) model for New Zealand (National Seismic Hazard Model, or NSHM). The new NSHM supersedes the earlier NSHM published in 2002 and used as the hazard basis for the New Zealand Loadings Standard and numerous other end‐user applications. The new NSHM incorporates a fault source model that has been updated with over 200 new onshore and offshore fault sources and utilizes new New Zealand‐based and international scaling relationships for the parameterization of the faults. The distributed seismicity model has also been updated to include post‐1997 seismicity data, a new seismicity regionalization, and improved methodology for calculation of the seismicity parameters. Probabilistic seismic hazard maps produced from the new NSHM show a similar pattern of hazard to the earlier model at the national scale, but there are some significant reductions and increases in hazard at the regional scale. The national‐scale differences between the new and earlier NSHM appear less than those seen between much earlier national models, indicating that some degree of consistency has been achieved in the national‐scale pattern of hazard estimates, at least for return periods of 475 years and greater.