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The 2022 New Zealand National Seismic Hazard Model Revision

Session: Recent Engineering Uses of National Seismic Hazard Models II

Type: Oral

Date: 4/22/2021

Presentation Time: 05:45 PM Pacific

Description: 

We are currently undertaking the most significant revision of the New Zealand National Seismic Hazard Model (NSHM) in more than 20 years. An international team of more than 50 scientists is contributing to three working groups: 1) Seismicity Rate Models (SRM); 2) Ground Motion Characterisation Models (GMCM); and 3), Service Delivery (SD). Within the SRM and GMCM a critical focus is on understanding and modelling of uncertainty. Particularly, this is on uncertainty in our knowledge (i.e., epistemic uncertainty) that we can model via the use of alternative models. In the SRM we will consider more ruptures than in past NSHMs. This includes complex multi-fault ruptures which were difficult to model in the past. While still possible to include, we will no longer by limited by strict fault segmentation and strictly characteristic earthquake behaviour. We will accomplish this using the USGS “inversion models” methods. Preliminary results are encouraging about our ability to apply this to the New Zealand fault system. This focus includes the Hikurangi subduction zone and the use of multiple recent data sets to constrain and better model the distribution of potential earthquakes on the interface. GMCM will use multiple recent international ground motion models. Where feasible, and significant for hazard, regional adaptations to the models will be implemented. This includes necessary improvements for near-source large magnitude events and modelling of non-linear site response. As with the SRM, the Hikurangi is a critical focus of the model which requires better modelling of ground shaking from Auckland through to Wellington.

Presenting Author: Matthew C. Gerstenberger

Student Presenter: No

Authors