Hazard modelling
What are coastal hazards
Coastal hazards include erosion, flooding, tsunami, cliff collapse, and effects from earthquakes or volcanic activity. These hazards are becoming more severe due to climate change and rising sea levels. Hazards can happen individually or in combination, and vary by location, intensity, and likelihood.
Why hazard modelling matters
Many coastal areas in New Zealand already have hazard zones mapped. Better data will help reduce disaster costs and save lives.
Accurate 3D elevation data (land and seabed) is essential to:
- understand shoreline changes and sea-level rise
- improve tsunami evacuation modelling
- support risk assessments and emergency planning.
Economic and planning benefits
Improved elevation data could save local councils up to $11 million annually. It also helps reduce infrastructure planning costs by around 1%.
Elevation data was used in past events like the Christchurch and Kaikōura earthquakes to assess land and seafloor changes.
Planning tools for managing risk
Coastal hazard data supports:
- spatial and growth planning
- regional and district plans
- asset and infrastructure planning
- community and collaborative planning
- future development strategies.
Māori perspectives and adaptation
Climate change will affect how whānau, hapū, and iwi interact with the environment and each other.
Many Māori communities live in coastal areas where marae, urupā, wāhi tapu, and mahinga kai are located. These sites are vulnerable to sea-level rise, flooding, and erosion.
Adaptation strategies must:
- protect Mātauranga Māori and customary practices
- future-proof cultural infrastructure
- ensure continued social and cultural wellbeing.
3DCM data will enable risk-informed decision-making by informing iwi and hapū about climate risks specific to their rohe. This data can be a resource for iwi and hapū to combine traditional knowledge with scientific insights, enhancing local climate resilience strategies.
Risk modelling
The Natural Hazards Commission (NHC) Toka Tū Ake uses risk modelling to assess and manage the potential impact of natural disasters in New Zealand.
This involves using RiskScape, a multi-hazard risk modelling tool developed by Earth Sciences New Zealand (formerly GNS Science and NIWA), to assess risk to buildings, infrastructure, and people and understand damage and losses from earthquakes, tsunamis, and other natural hazards.
View more information on RiskScape.
NHC’s risk modelling efforts are crucial for planning, response, and securing reinsurance, contributing to New Zealand's overall resilience to natural hazards.
3D Coastal Mapping will add value by providing high-resolution, integrated data that enhances the accuracy, scope, and responsiveness of hazard assessments across New Zealand’s vulnerable coastal zones.
By combining topographic (land) and bathymetric (underwater) data, the programme supports seamless modelling across the land–water interface, which is often a blind spot in traditional risk models.
LiDAR data can also be quickly updated after natural disasters to assess:
- coastal morphology changes
- infrastructure damage
- water level and surge extent.
This improves situational awareness and speeds up emergency response and recovery efforts.
Tsunami modelling
Understanding tsunami risk
Aotearoa New Zealand’s tsunami risk is not well understood, with only one recorded fatality since the 1840s. New modelling shows major cities are exposed to tsunami threats from multiple sources.
A worst-case 1-in-500-year tsunami could cause:
- up to 33,000 deaths
- 27,000 injuries
- $45 billion in property damage.
These estimates assume limited evacuation and a night-time event when people are at home.
Why elevation data matters
Accurate elevation and seabed data is essential for:
- predicting tsunami inundation patterns
- designing evacuation plans
- creating high-resolution hazard maps.
Near-shore elevation data helps model how tsunami waves interact with the coastline, improving risk zoning and response planning.