Posted: 4 October 2022
What is the National Seismic Hazard Model?
The National Seismic Hazard Model (NSHM) provides an estimate of the likelihood and strength of earthquake ground shaking that might occur at any given site in New Zealand. It provides information about how different parts of the country might behave in the event of large magnitude earthquakes.
The model helps deliver science-based estimates that are essential for Aotearoa New Zealand to develop risk assessments and manage risks to safety, security and the economy from seismic events.
The NSHM is a part of Aotearoa New Zealand’s science ‘infrastructure’, helping to inform technical standards for earthquake engineering design as well as providing critical information for earthquake risk management relevant to insurance, infrastructure management and emergency planning and response.
How is the National Seismic Hazard Model used?
The NSHM is used broadly by organisations and decision makers that need to estimate the likely impact of earthquakes on Aotearoa New Zealand’s land, buildings, and infrastructure.
The model guides seismic risk communication for civil defence planning and community resilience, for road and rail infrastructure planning, and to help insurance companies assess risk. It helps in the management of government owned assets and in determining how buildings and structures need to be designed and constructed.
The NSHM revision results are now publicly accessible as well as a suite of information about the model and how to interpret it such as:
- Model results
- Explainer Video
- Results Video
- Fact sheets to explain the science aspects
- Regional information sheets
Access the NSHM results - GNS Science
What does the NSHM mean for building regulations?
MBIE uses the NSHM to help inform the risk settings in our building regulations and to improve the safety of buildings across New Zealand. Time will be required to determine how the revised hazard information will be applied.
Continue to use existing law, technical standards and guidance
The updated NSHM results do not automatically change how we design buildings. Building professionals and practitioners should continue to use existing law, technical standards and guidance to demonstrate that their work complies with the Building Code.
MBIE will carefully consider what the updated NSHM means for new building design standards. It is currently working with Engineering New Zealand to assess what changes to building design standards are required, and how to include the NSHM results in regulatory settings for new buildings.
At this stage, MBIE is planning to consult on an initial set of proposed changes to building standards in mid-2023. However, the timing for this consultation will depend on how long it takes to develop technically robust proposals. MBIE will be able to confirm the timeframes for consultation in the coming months.
The updated NSHM results do not change the way seismic assessments are done on existing buildings. MBIE, in collaboration with the engineering technical societies NZSEE, SESOC and NZGS, are currently considering whether to change the hazard used in seismic assessments if updates to new building design standards are made.
There are no plans for MBIE to change the legislation that governs the earthquake-prone building system as a result of the updated NSHM.
Keep designing to the highest possible safety standard
MBIE encourages the sector to keep building to the highest possible safety standards where practical and to use new guidance and advisories developed and released by the engineering technical societies NZSEE, SESOC and NZGS.
Earthquake design for uncertainty
This guidance recommends approaches an engineer can take to help ensure reliable seismic performance from a building, regardless of uncertainty in the seismic hazard.
Interim Advice for National Seismic Hazard Model
This new advisory document provides interim advice for the timeframe between the NSHM release any future Building Code update.
If you have any questions about the NSHM and what it means for building regulations, you can contact us by email email@example.com.