NSHM - National Seismic Hazard ModelTe Tauira Matapae Pūmate Rū i Aotearoa
The National Seismic Hazard Model calculates the likelihood and strength of earthquake shaking that may occur in different parts of Aotearoa New Zealand over specified time periods.
It is critical information, used by government and industry to help improve national resilience and manage risks to safety, security and the economy from seismic events.
New Zealand continues to be challenged by earthquakes and, because of our geographical make-up, it always will be. Fortunately, globally, our understanding of earthquake science has improved exponentially. We now know a lot more about earthquake hazard and its impacts than we did previously, so we can prepare better and make good decisions.
An important part of New Zealand’s hazard-scape toolkit, the National Seismic Hazard Model provides an estimate of the likelihood and strength of earthquake ground shaking at any given site in New Zealand and considers how different parts of the country might behave in the event of large magnitude earthquakes. It is 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.
Explaining the National Seismic Hazard Model 2022 transcript
Aotearoa New Zealand sits aside tectonic plates and that puts the country at risk of earthquakes.
Knowing how strong future earthquakes shaking might be helps us to understand the risks to our communities.
The more we know, the better we can prepare, make good decisions, and increase our resilience to earthquake hazard events.
And the world is continually learning with new information resulting from every new earthquake event.
Developed using the best available science in the world,
the New Zealand National Seismic Hazard Model is our future earthquake knowledge toolkit.
The National Seismic Hazard Model is a science based, agreed estimate of the likelihood and strength of earthquake shaking throughout New Zealand.
It's a detailed model to help decision makers manage the risks, the losses due to earthquakes throughout New Zealand.
The New Zealand Seismic Hazard Model is an amalgam of many models.
It incorporates, I don't know, thousands of different models of earthquake occurrence over different time frames, looking at it from different angles, and it's all there to bring together the most comprehensive view and understanding of earthquake occurrence throughout New Zealand.
So the National Seismic Hazard Model is a probabilistic model, and why that's important is because it's not earthquake predictions.
We can't predict earthquakes.
We don't have the understanding to be able to do that.
So the reason it's probabilistic
is because that's the way that we can bring in a broad range of our scientific understanding and put that into a form that can be understood by others and used for decision making.
With this science New Zealand decision makers such as the Ministry of Business, Innovation and Employment,
Toka Tū Ake EQC, local government and our emergency management agencies can make informed decisions in our policy and practice.
The University of Canterbury is a major contributor to the National Seismic Hazard Model project, along with many other tertiary and crown research institutions in New Zealand and in combination with a significant number of international partners.
We've learned significant new aspects of the earthquakes, particularly on the backbone of the 2010 and 2011
Canterbury earthquakes as well as the 2016 Kaikoura earthquake.
Some of the important things that we've learned is increased understanding of the nature of earthquakes and the complexity of earthquakes.
We saw in the Canterbury and Kaikoura earthquakes how individual faults can connect together to cause complicated earthquake sequences, and the new New Zealand National Seismic Hazard Model has the ability to account for such complexity in earthquake occurrence.
It will lead to significant improvements in our ability to forecast the nature and strength of earthquake induced ground motion shaking, which will lead to more efficient design of societal infrastructure so that we can find the right balance between upfront costs to build resilience and the long term impacts of that resilience.
One of the big advantages that we have now is the availability of high performance computing and how we can run much more complex models than we could have done in the past to account for many more things that are happening in the earth and to account for much greater uncertainties.
We model hundreds of thousands of potential earthquakes around the country and these earthquakes connect up different faults in the system and looks at how they may interact together.
And there's the big ones, like everybody knows about the Alpine fault, the Wellington fault, and of course, the Hikurangi, which we've learned a lot about the subduction zone in the last 10 or 20 years.
Those are those are big, important Earthquake sources for the future of New Zealand, but there's also many other potential earthquake sources around the country.
One of the things that's been quite important to us as we've been putting the model together, is that anything we're doing, we want to make sure is openly available to anyone who might want to use it or is interested in it or needs to use it. So all of the outputs of the model, the model itself, all of that is is easily available. It's available online.
You can look at different maps.
You can look at special technical curves that engineers might be interested in.
There's a whole lot of different ways you can look at what's come out of the model and how that may be important to you and where you particularly live.
We've been working on the seismic hazard model for a couple of years now.
It's involved a team of 50 or 60 scientists and engineers nationally, internationally recognized, and that was super important, so we could enfold, we can take on board scientific understanding throughout the globe on how it impacts our assessment of ground shaking throughout New Zealand.
Knowing as much as we can about earthquake
hazards and risk is only one part of New Zealand's safety plan.
The next is integrating that knowledge with the people who can use that information.
Estimating the likely impact of future earthquakes on New Zealand land, buildings, infrastructure and people is essential to help us be as safe and as prepared as we can be.
Explaining the National Seismic Hazard Model 2022
Aotearoa New Zealand sits aside tectonic plates and that puts the country at risk of earthquakes....
The NSHM presents a range of maps, hazard curves and reports that can be used to provide a forecast of the earthquake shaking expected over, for example, the next 10, 50 or 100 years at a range of probability levels.
It is complex science, so we have provided lots of information to help interpret what it means. The following fact sheets, video and regional summaries will help you understand the results.
Ready to view the full NSHM results? Click here(external link).
Otherwise, keep reading to learn more.
The NSHM is world leading science that has been developed and reviewed by many national and international experts. Building the model is complex, a little like building a million-piece puzzle. Scientists study hundreds of thousands of models, almost a million in fact, which all contribute to the final model. The NSHM is very robust, and the science is trusted by the many different decision makers that apply it in their risk assessments.
The 2022 review of the NSHM was led by GNS Science, and funded by MBIE and Toka Tū Ake EQC.
GNS Science, MBIE, Toka Tū Ake EQC, engineers, universities and other Crown Research Institutes worked together closely on the revision of the model and many local and international scientists and academics have been involved in its development.
GNS Science is the custodian of the NSHM. Key users of the model include MBIE, Toka Tū Ake EQC, local and regional authorities, Waka Kotahi NZTA, structural and geotechnical engineers, land-use planners, seismic hazard consultants, risk modelling consultants, and the insurance sector.
What the results tell us
The 2022 revision of the NSHM estimates the likelihood of future earthquake shaking hazard to have increased throughout most of the country, ranging from almost no change to more than doubling in some areas.
On average, results have increased by 50 percent or more from previous modelling, highlighting the need to boost national resilience strategies and readiness.
The NSHM does not describe impact, or assess associated risk. Instead, the model is a science instrument which can be used by government and industry to estimate risk and help make risk-based decisions.
The 2022 revision of the NSHM shows that seismic hazard has increased almost everywhere throughout Aotearoa New Zealand compared to what we knew previously. This is not unexpected, because:
- We now know a lot more about earthquake behaviour due to better global understanding, more sophisticated science, and more than a decade of advancements in technical computing.
- We now have an improved model of the variability in shaking from potential earthquakes that could rupture in any single location. One significant contributor is the Hikurangi Subduction Zone, another is the Alpine Fault. These are important sources, but we also model the likelihood for earthquakes on unknown (hidden) faults and how shaking can affect regions far from the epicentre.
- We can model low probability but potentially high impact events affecting New Zealand, by understanding how faults can link together.
Earthquake hazard varies throughout the country based on the geography and ground conditions in each location, and the frequency and types of earthquakes which might occur.
The NSHM provides multiple results for each location, and they must be considered together to fully understand the hazard. A single aspect of the results considered on its own cannot reflect the level of hazard for a location.
Watch the National Seismic Hazard Model webinar to learn more about the science behind the model.
Why we need seismic hazard modelling
Aotearoa New Zealand experiences around 250 felt earthquakes every year (on average) and thousands more are measured. Understanding the likely strength of ground-shaking from future earthquakes is essential for a range of safety, security, resilience, financial, and economic purposes, including to:
- provide a national assessment of New Zealand’s seismic hazard
- inform the settings in the Building Code
- inform the standard for seismic resilience for the development of other infrastructure, such as dams, roads and bridges, through guidance such as the New Zealand Dam Safety Guidelines and Waka Kotahi’s Bridge Manual
- support risk communication, emergency management, business continuity planning, and community resilience
- contribute to natural hazard risk and loss models, including those used for insurance and reinsurance purposes, as well as local government resource management and land use planning
For more information from our agency partners:
- For information about how the NSHM will be considered by insurers, go to Toka Tū Ake EQC(external link)
- For more information about how MBIE uses the National Seismic Hazard Model to help inform the risk settings in our building regulations and to improve the safety of buildings across New Zealand, visit: MBIE Building Performance(external link)
- For information about how you can prepare and protect your whānau from earthquakes, go to the National Emergency Management Agency (NEMA) Get Ready webpage(external link).
- For information about how you can help protect your home, workplace, schools and the places you spend time in from earthquakes, go to Toka Tū Ake EQC Be Prepared webpage(external link).
How the NSHM impacts New Zealanders
The model is used by a variety of end-users to estimate the likely impact of earthquakes on New Zealand land, buildings, infrastructure, and people. It is world-leading science that helps improve our understanding of the impacts of earthquake shaking and allows us to increase our resiliency to earthquake hazard.
The science is the first step. The revised NSHM will be taken into consideration by government and industry, before any decisions and changes are made and brought into policy and practice. Any changes will take time to determine and these will be communicated directly by the responsible agencies.
The update is a joint initiative being led by GNS Science, the Ministry of Business, Innovation and Employment, and the Earthquake Commission. It involves the collective knowledge and skills of a large team of national and international scientists and end-users. The revised NSHM including its component-models and outputs are freely available(external link).
Building the NSHM
The GNS Science-led National Seismic Hazard Model (NSHM) is a collection of multiple models which together estimate future earthquake shaking in New Zealand. These models represent the broad range of our knowledge (and uncertainty) about how earthquakes occur and how earthquakes cause the surface of the Earth to shake.
By combining multiple models, the NSHM can incorporate scientific understanding of earthquakes acquired from diverse research fields, ranging from paleoseismology (study of historic earthquakes), geodesy (study of the Earth’s shape and gravity field) and geophysics (study of the physics properties and processes of the Earth), through to engineering seismology (study of earth science and civil engineering to understand seismic hazard).
The NSHM consists of two primary components:
- Seismicity rate models: these model potential earthquake sources
- Ground motion characterisation models: these model how shaking from an earthquake changes as it travels through the Earth’s crust
These components are then combined to estimate ground shaking hazard.
2010 National Seismic Hazard Model
The 2010 National Seismic Hazard Model is the latest revision of the NSHM for New Zealand and was published in 2012. While not considered in the building code, this model has been used in site-specific studies since its publication.
Gerstenberger MC, Stirling M, Harte D. 2014. Rethinking PSHA: Summary of Research Prioritisation Workshops(external link). Lower Hutt (NZ): GNS Science. 51 p. (GNS Science report; 2014/48).
Summarises the results of a series of research prioritisation workshops held for the Rethinking PSHA project. Workshops covered earthquake source modelling and ground motion modelling for revising the New Zealand National Seismic Hazard Model.
Gerstenberger MC, Stirling MW, McVerry G, Rhoades D. 2015. The New Zealand National Seismic Hazard Model: Rethinking PSHA.(external link) Proceedings of the Tenth Pacific Conference on Earthquake Engineering, Sydney (Australia).
Explores some fundamental assumptions of the New Zealand NSHM and investigates the effects of uncertainties in earthquake source and ground modelling on end uses of the model.
Gerstenberger MC, McVerry G, Rhoades D, Stirling M. 2014. Seismic hazard modelling for the recovery of Christchurch(external link), Earthquake Spectra, 30(1), 17-29. doi:10.1193/021913EQS037M.
This paper provides an overview of the time-dependent seismic hazard model developed to aid in the recovery of Christchurch during the ongoing Canterbury earthquake sequence.
Gerstenberger MC, Rhoades D, McVerry G. 2016. A hybrid time–dependent probabilistic seismic hazard model for Canterbury, New Zealand(external link). Seismological Research Letters. 87(6):1311– 1318. doi:10.1785/0220160084.
Discusses the development of a hybrid time-dependent seismic hazard model for Canterbury to aid in recovery during the Canterbury earthquake sequence.
Gerstenberger MC, Marzocchi W, Allen T, Pagani M, Adams J, Danciu L, Field EG, Fujiwara H, Luco N, Ma K-F, Meletti C, Petersen MD. 2020. Probabilistic Seismic Hazard Analysis at Regional and National Scale: State of the Art and Future Challenges(external link) Reviews of Geophysics, e2019RG000653; First published 1 March 2020.
This review paper describes the state of the art in modeling earthquake hazard at the national scale.
McVerry GH, Zhao JX, Abrahamson NA, Somerville PG. 2006. New Zealand Acceleration Response Spectrum Attenuation Relations for Crustal and Subduction Zone Earthquakes(external link), Bulletin of the New Zealand Society for Earthquake Engineering, 39(1): 1-58.
This paper describes the ground motion model, or attenuation relationship, used in the 2010 NSHM and in numerous seismic hazard studies. Please note a correction to the site term equation (equation 4) of the McVerry et al. paper is available here: Site Term Correction.pdf(external link) (20.34 kB)
Stirling MW, McVerry GH, Berryman KR. 2002. A new seismic hazard model for New Zealand(external link), Bulletin of the Seismological Society of America, 92(5):1878-1903.
This paper discusses the 2002 National Seismic Hazard Model, which is the foundation of current earthquake loading requirements in New Zealand.
Stirling MW, McVerry GH, Gerstenberger MC, Litchfield NJ, Van Dissen RJ, Berryman KR, Barnes P, Wallace LM, Villamor P, Langridge RM, Lamarche G, Nodder S, Reyners ME, Bradley B, Rhoades DA, Smith WD, Nicol A, Pettinga J, Clark KJ, Jacobs K. 2012 National seismic hazard model for New Zealand : 2010 update.(external link) Bulletin of the Seismological Society of America, 102(4): 1514-1542; doi: 10.1785/0120110170
The 2010 National Seismic Hazard Model is a revision of the 2002 NSHM published in 2012 ,incorporating additional fault sources and updated distributed seismicity to produce revised hazard maps.
Van Houtte C, Bannister S, Holden C, Bourguignon S, McVerry G. 2017. The New Zealand Strong Motion Database.(external link) Bulletin of the New Zealand Society for Earthquake Engineering. 50(1):1–20
Provides information on the work undertaken to compile the New Zealand Strong Motion Database (NZSMD), which contains 276 New Zealand earthquakes recorded by strong motion instruments from GeoNet and earlier network operators. The NZSMD is intended as a resource for both researchers and practitioners.
Van Houtte C. 2017. Performance of response spectral models against New Zealand data.(external link) Bulletin of New Zealand Society for Earthquake Engineering. 50(1):21–38
Analysis of New Zealand and international ground motion models against the New Zealand Strong Motion Database, justification for use of global models, and some recommendations for model usage in seismic hazard analysis.
Van Houtte C, Abbott ER. 2019. Implementation of the GNS Science Canterbury Seismic Hazard Model in OpenQuake(external link). Lower Hutt, N.Z.: GNS Science. GNS Science report 2019/11. 38 p.; doi:10.21420/1AEM-PZ85.
This report provides detail of the efforts to implement the Canterbury Seismic Hazard Model (CSHM) in OpenQuake.
Van Houtte C, Abbott ER 2019. OpenQuake implementation of the Canterbury seismic hazard model.(external link) Seismological Research Letters, 90(6): 2227-2235; doi: 10.1785/0220190100 [November 2019]
This article describes the release of the CSHM as implemented in OpenQuake, including practical constraints and issues for consideration in the development of future models.
Van Houtte C. 2020. Preliminary common-form ground-motion models for shallow crustal earthquakes and their use in ergodic and partially-ergodic seismic hazard calculations in New Zealand.(external link) Lower Hutt (NZ): GNS Science. 91p. (GNS Science report; 2020/02). doi:10.21420/ZMCK-R234
This study derives suites of nonredundant ground motion models for shallow crustal earthquakes that are designed to capture the full space of technically defensible models for seismic hazard assessment. This study is intended to open a discussion on what a final suite of shallow crustal ground motion models could look like.
Our project team
Core NSHM team
This working group is primarily responsible for deciding the direction of the National Seismic Hazard Model framework, with input and advice from the Technical Advisory Group (TAG), and for assimilating the outputs of all other working groups into the final project deliverable.
The Core NSHM team comprises:
- Matt Gerstenberger (Project Lead) – GNS Science
- Russ Van Dissen – GNS Science
- Brendon Bradley(external link) – University of Canterbury
- Chris DiCaprio – GNS Science
- Anna Kaiser – GNS Science
- Andy Nicol(external link) – University of Canterbury
- Kiran Thingbaijam – GNS Science
- Mark Stirling(external link) – University of Otago
- Rachel Kirkman – GNS Science
Seismicity Rate Models (SRM) working group members
The Seismicity Rate Model (SRM) Working Group is comprised of New Zealand and international scientists from GNS, universities, consultancies, and other Crown Research Institutes. This working group is responsible for the development of multiple models that will represent the magnitudes, locations, and rates of potential future earthquakes. This work, while still being prioritised, will likely cover the following topics to varying extents
- Andy Howell(external link) – GNS Science/University of Canterbury
- Annemarie Christophersen – GNS Science
- Bruce Shaw(external link) – Columbia University, Lamont-Doherty Earth Observatory
- Charles Williams – GNS Science
- Chris Rollins – GNS Science
- David Burbidge – GNS Science
- David Rhoades – GNS Science
- Francesca C. Ghisetti(external link) – TerraGeoLogica
- Genevieve Coffey – GNS Science
- Hannu Seebeck – GNS Science
- Ian Hamling – GNS Science
- Jade Humphrey(external link) – University of Canterbury
- Jeff Fraser(external link) – Golder Associates
- Jeremy Maurer(external link) – Missouri University of Science & Technology
- Jonathan Griffin(external link) – Geoscience Australia/University of Otago
- Joshu Mountjoy(external link) – NIWA
- Kaj Johnson(external link) – University of Indiana
- Kate Clark – GNS Science
- Kiran Thingbaijam – GNS Science
- Laura Wallace – GNS Science
- Nicola Litchfield – GNS Science
- Philip Barnes(external link) (NIWA)
- Pilar Villamor – GNS Science
- Rob Langridge – GNS Science
- Tim Stahl(external link) – University of Canterbury
- William Power – GNS Science
- Sandra Bourginon – GNS Science
- Sepi Rastin – GNS Science
Ground Motion Characterisation Models (GMCM) working group members
The Ground Motion Characterisation Models Working Group (GMCM) is comprised of New Zealand and international scientists from GNS Science, universities, consultancies, and other Crown Research Institutes. This working group is responsible for developing and determining the use of multiple ground motion models (GMM) for estimating ground shaking based on the occurrence of any particular earthquake source as modelled by the SRM working group.
- Brendon Bradley(external link) – University of Canterbury
- Anne Hulsey(external link) – University of Auckland
- Chris de la Torre (external link) – University of Canterbury
- Danijel Schorlemmer(external link) – Das Deutsche GeoForschungsZentrum
- Elena Manea – GNS Science
- Graeme Weatherill(external link) – Das Deutsche GeoForschungsZentrum
- Hadi Ghesemi – Geoscience Australia
- Jesse Hutchinson (external link)– University of Canterbury
- Liam Wotherspoon(external link) – University of Auckland
- Matt Hill – GNS Science
- Nicolas Kuehn(external link) – UCLA
- Pablo Iturrieta(external link) – Das Deutsche GeoForschungsZentrum
- Robin Lee(external link) – University of Canterbury
- Sanjay Bora – GNS Science
- Scott Nodder(external link) – NIWA
- Viktor Polak – University of Canterbury
Service Delivery working group members
This working group is focused on the delivery of the NSHM in a way that is transparent and openly available to the end-user community. The end goal is for providing the NSHM and results in a manner that is thoroughly documented, fit-for-purpose, open-source and web-based.
To ensure usability and uptake, this group is also responsible for soliciting end-user input across the entire model development process, including through the Technical Advisory Group.
- Chris DiCaprio – GNS Science
- Ben Chamberlain
- Chris Chamberlain – GNS Science
- Kevin Milner(external link) – University of Southern California
- Oakley Jurgens – GNS Science
- Qianye Lin
Technical Advisory Group members
Andreas Giannakogiorgos – Tetra Tech Coffey / NZGS representative
Philip Conway – IAG
Delphine Fitzenz – RMS
Gail Atkinson – Private Consultant
Reza Esfandiari Sedgh – MBIE
John Townend – Victoria University
Ken Elwood – Univeristy of Auckland, Chief Engineer for MBIE & EQC
Rowan Ballagh – Dunning Thornton Consultants
Marco Pagani – Global Earthquake Model Foundation (GEM)
Mike Stannard – Private Consultant
Ned Field – United States Geological Survey
Nico Luco – United States Geological Survey
Nick Horspool – GNS / EQC representative
Peter Stafford – Private Consultant
Rick Wentz – Wentz-Pacific Ltd / NZGS representative
Tony Holden – Aurecon / NZSEE representative
Trevor Allen – GeoScience Australia
Research Project Details
Collaborators: GNS Science, University of Canterbury, University of Otago, Auckland University, Geoscience Australia, University of Southern California, UCLA, US Geological Survey, NIWA, Global Earthquake Model (GEM) Foundation, WSP Golder, Missouri University of Science & Technology, Indiana University, Das Deutsche GeoForschungsZentrum (GFZ), Lamont-Doherty Earth Laboratory – Columbia University
2020 – present
MBIE Building Systems and Performance (BSP), EQC
Dr Matt Gerstenberger
Ministry of Business, Innovation and Employment (MBIE), Toka Tū Ake EQC