Back in 2006, IT’S OUR FAULT supported Wellington to become a more resilient city through a comprehensive study of the likelihood of large Wellington earthquakes, their effects and impacts on humans and the built environment.
Today, the programme is supporting the region's growing resilience with targeted science and policy research projects in line with community and local government needs.
Active faults account for c. 50% of the strain accumulation and release across the Australian-Pacific plate in the WellingtonRegion. While the activity and hazard posed by the first order faults (Wairarapa, Wellington, Ōhāriu) is quite well known, there is much less known about second order faults. Several “new” second order active faults have been identified near population centres in the Wairarapa in recent years and preliminary work on four of these faults showed that slip rates and recurrence intervals may be similar to the Masterton andCarterton faults. Paleoearthquake records for all of these second order faults are relatively poor, limiting our ability to robustly forecast the earthquake hazard.
This project will be undertaken over two years.Fieldwork (trenching), dating and preliminary analysis will be undertaken in2025-2026 on two of these second-order faults. Sites will be selected in consultation with mana whenua and archaeological authorities obtained if required. In 2026-2027 the results will be compared with those from nearby faults (e.g., the Wairarapa Fault) and the Hikurangi Subduction Zone, to examine the potential for fault interactions. Results from this work will lead to improved outcomes for models that feed the National Seismic Hazard Model including the Community Fault Model, Paleoseismic Site Database and NZ ActiveFaults Database.
The central section of the Alpine Fault has a 75% probability of rupture in the next 50 years and the 2022 update to the National Seismic Hazard Model revealed credible Alpine Fault rupture scenarios that could produce significant ground shaking in the Wellington Region. New ground motion simulations produced in FY24-25 of the IOF programme will be used to assess the potential impacts across multiple sectors within the region using risk modelling.
The project will start with a stakeholder meeting to select the impact models to be included and the outputs required.This will determine the modelling software used for the modelling and all will benefit from recent improvements in data availability and vulnerability/fragility functions. The results will be presented tostakeholders and published in a report. The modelling workflows will be set upto be easily applied to other scenarios (e.g. Hikurangi subduction zone earthquakes), and the modelling outputs will be able to be used in other projects.
A pilot study was undertaken in 2023-24 at Takapūwahia Marae, Porirua, with Ngāti Toa Rangatira to assess the impacts of multi-hazards (earthquake shaking, tsunami, liquefaction, landslides) to its facilities and community. This mahi supports decision-making, raising awareness and education and there is significant interest among other Iwi, and demand for this work for other marae in the region.
Building upon the lessons learnt from the pilot study, the team will work with Māori, Iwi partners and the IOF Programme committee to identify and codesign future case studies in the Wellington Region. A desk-based assessment will be undertaken in 2024 of the vulnerability of marae and communities to natural hazards and to identify potential communities for future engagements. These engagements will be held in 2025 to socialise the project, assess demand, interest and capacity, and to codesign projects at two marae in 2025-2026.
A core part of the Planning and Policy project, and its predecessors, are the Science to Practice Workshops.
A core part of the Planning and Policy project, and its predecessors, are the Science to Practice Workshops. For 2025–2026 the Planning and Policy workstream will focus on completing a multi-council Science to Practice Workshop. The team will work to establish a relationship and understanding of the natural hazard planning challenges the councils face and tailor a workshop to assist in addressing these challenges.
It’s Our Fault programme datasets are currently not explicitly publicly released (e.g.,on the IOF website), or consistently hosted on a single website or portal. In 2024-2025 a stocktake was undertaken of legacy datasets to assess which datasets should be made available and to develop a plan for making them available. This assessment found that there are only a handful of datasets that are not currently available in some form. These, and any new datasets from2024-2025, will be made available on at least one platform, accompanied with appropriate metadata.