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National Seismic Hazard Model Programme

seismic model

This map shows the 2% probability of exceedance of peak ground acceleration (PGA) from earthquake shaking in any 50-year time window. These results were produced for NZ Class C shallow soil. The map is produced from the OpenQuake-adapted version of the corrected 2010 National Seismic Hazard Model (Stirling et al. 2012).

What is the National Seismic Hazard Model?
The New Zealand National Seismic Hazard Model (NSHM) is a model that calculates the likelihood and strength of earthquake shaking occurring in different parts of New Zealand. 

In a nutshell – The NSHM is a collection of many different models that are combined together to estimate future earthquake shaking in New Zealand. These models represent the broad range (and uncertainty) of our knowledge about how earthquakes occur – and also about how earthquakes cause the surface of the earth to shake. We use a collection of different models because each model allows us to include a different scientific possibility. These results help understand the expected shaking in, for example, the next 10, 50 or 100 years.

The model incorporates scientific understanding of earthquakes acquired from diverse research fields ranging from paleoseismology, geodesy, and geophysics, through to engineering seismology.

The NSHM consists of two primary components:

  • seismicity rate models – these model potential earthquake sources
  • ground motion characterisation models – these model how energy from an earthquake attenuates as it moves through the earth.

Outputs - It delivers estimated shaking outputs based on the best available science for New Zealand to manage resilience and understand risks to safety, security, and the economy from seismic events.

There are many outputs of the model including a series of nationwide maps for New Zealand that provide a forecast of the earthquake shaking expected over, for example, the next 10, 50 or 100 years at a range of probability levels.

Who uses the NSHM?    

The model is used by a variety of end-users to estimate the likely impact of earthquakes on New Zealand land, buildings, and infrastructure. This helps to understand the impact of earthquake hazard on society and increase resiliency.

Key users include MBIE, EQC, local and regional authorities, NZTA, structural and geotechnical engineers, land-use planners, seismic hazard consultants and risk modelling consultants, and the insurance sector.

GNS Science is the custodian of the NSHM.

Revising the model

The NSHM is being revised over a period of 2.5 years from 2020 to 2022. GNS Science is leading the research work.

Scientific knowledge and best practice have significantly advanced since the last updates of the NSHM in 2002 and 2010. The NSHM is being revised to reflect this, particularly international best practice and learnings from the Canterbury earthquake sequence and the Kaikōura earthquake.

The revised NSHM including its component-models and outputs will be freely available.

Who is involved in revising the NSHM?

Expert end-users, New Zealand scientists and international scientists are involved in developing the revised NSHM. These people include scientists and end-users from New Zealand and overseas universities, science institutions, and consultancies.

  • Project Governance Group: Comprises senior managers from GNS Science, MBIE and EQC.
  • Project Lead: Dr Matt Gerstenberger, GNS Science.
  • Project Manager: Rachel Kirkman, GNS Science.
  • Technical Advisory Group: Ensures the model and its outputs are based on best available science, and that it provides the information needed by end-users. Find out more. 
  • Working Groups: Core NSHM, Seismicity Rate Models, Ground Motion Characterisation Models, Service Delivery. Find out more.

Find out more about the NSHM programme

Contact us here if you would like to know more about the NSHM Programme.

Listen to Dr Matt Gerstenberger talk about the NSHM (2-minute audio clip) on RNZ National.

Read the news release announcing the NSHM revision project, 6 August 2020.

Working groups and governance for NSHM Programme
Technical Advisory Group; Strategic Stakeholder Group; Project Steering Group;Core NSHM; Seismicity Rate Models; Ground Motion Characterisation Models; Service Delivery.

Previous seismic hazard models
Comprises the 2002 NSHM as used for NZS1170.5; the 2010 NSHM; and the Canterbury Time-dependent Seismic Hazard Model.

Glossary and FAQs
About the science, process for revision and impact of the NSHM.

Relevant publications
Scientific papers and reports relating to national seismic hazard modelling.

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