Common questions on tsunami maps

Our Emergency Management team works closely with our local community to incorporate feedback into our planning. The community have told us three evacuation zones is confusing, which is why we now only have one evacuation zone and colour. This makes our maps simpler and easy to read.

The maximum credible tsunami could be generated by an earthquake along the Kermadec Trench, north-east of New Zealand. To produce a tsunami of this height, the earthquake would need to be greater than magnitude 9.

Most other tsunami scenarios modelled are not as damaging as the Kermadec scenario. While most tsunami have potential to affect our marine and beach areas, only a rare tsunami could potentially overtop some of the dunes along our coastline. A tsunami from White Island is unlikely to overtop the dunes.

A tsunami inundation area is the area of land that could be covered (or “inundated”) by water if a tsunami were to occur. It’s based on computer modelling that predicts how far inland tsunami waves could reach, depending on their size and source. These areas are used for planning and awareness, so people know which areas are at risk. You can view the tsunami inundation areas on Bay of Plenty Regional Council’s Bay Explorer online map at https://maps.boprc.govt.nz/pages/bayexplorer (Click on the RHS 'Open BayExplorer' Tab, select Natural Hazards and then Tsunami Inundation).

Tsunami evacuation zone maps show where people should go to be safe during a tsunami. A tsunami evacuation zone map shows the areas people need to move out of if there’s a tsunami warning. It’s designed for public safety, not for property planning. The map highlights safe routes and areas to evacuate to, so people know where to go to stay out of danger. You can see the tsunami evacuation zone maps with the blue evacuation zone on our webpage at www.tauranga.govt.nz/tsunami or on the Bay of Plenty Regional Council’s BayExplorer webpage (Tsunami Evacuation Zone Layer) at https://maps.boprc.govt.nz/pages/bayexplorer (Click on the RHS 'Open BayExplorer' Tab, select Natural Hazards and then Tsunami Inundation).

The science used for tsunami modelling is always improving. The new data on tsunami inundation prepared by the Bay of Plenty Regional Council was recently provided to Tauranga City Council. This will be used to update our tsunami evacuation zone maps early in 2026.

Yes, only if your property is within the updated tsunami inundation zone. It is a legal requirement for Tauranga City Council to put this updated information on a LIM. You can access your full property file via https://www.tauranga.govt.nz/propertyfiles. The new raw data in an online map format can be viewed on Bay of Plenty Regional Council’s Bay Explorer online map at maps.boprc.govt.nz/pages/bayexplorer.

The Insurance Council of New Zealand has provided Tauranga City Council with an overview of how modelling and data on natural hazards affects property insurance. The overview can be found here www.tauranga.govt.nz/insurance-council-letter. We recommend it is best to talk with your own insurer for more details specific to your property.

Property values are influenced by many factors and are determined by the real estate market. While tsunami risk mapping may be one consideration for some buyers, other factors such as location, amenities, and market conditions typically have a greater influence on property values. If you have specific concerns about your property value, we recommend speaking with a qualified real estate professional who can provide advice based on current market conditions and your individual circumstances.

Research associated with this new modelling data was undertaken by GNS with peer reviewing by NIWA.

Updating tsunami evacuation zone maps is a complex process that requires combining detailed scientific data with considerations for the number of people living in specific areas, the local roading layout, and other practical and social factors, which takes a significant amount of time.  The new tsunami inundation data is available to the public now and our tsunami evacuation zone maps will be updated using this new data in early 2026.

The new modelling is also based on a 2,500-year return period tsunami for the Tauranga region. To identify the maximum impacted area GNS modelled tsunami generated by 18 different earthquake scenarios including several of different magnitude and location on the Kermadec Subduction Zone. The modelling is based on the most up to date understanding of tsunami generation using a model that has been internationally validated on past tsunami events.

Council has established a network of signposted tsunami evacuation routes through beach access points, park reserves and other significant areas. We have placed tsunami evacuation information boards along the routes inland, and there are tsunami direction signs guiding people along the most appropriate pathway out of the tsunami inundation zone.

We are regularly involved in raising community awareness around the risk of tsunami in Tauranga, through delivery of talks with schools and retirement villages; provision of evacuation maps at our local beaches; encouraging the community to create their own evacuation household plans; and practice their evacuation route. We have also started working with the community on a Community-led Evacuation Working Group. Council is part of the Bay of Plenty region’s Tsunami Ready Programme, for improved planning and coordination.

The evacuation maps are based on our current best knowledge. The knowledge includes in-depth studies undertaken in 2012, 2013, 2014, 2015, 2020 and 2025 by GNS Science and Tonkin and Taylor. These studies are peer reviewed by technical experts to ensure they are accurate and utilise the most up to date information and methods of research available. They have also included learnings from international tsunami examples to ensure we are working to the best information possible.

Our dune system is an excellent first line of defence against all tsunami. The tsunami water will lose a lot of power as it encounters the dunes, even as it overtops them or travels around them. There is also a secondary dune system at Mount Maunganui. Some of the roads sit quite a bit higher than the streets either side. The tsunami water will lose a lot of power as it encounters the dunes, overtops them or travels around them. Meanwhile, the tsunami entering from the harbour side will be significantly lower than the ocean side because much of its energy and power is lost as it squeezes through the harbour entrance.

The dune system along Papamoa has an average height above mean sea level of about 8m, so when a 14m wave hits the dunes, only the top 6m of the wave flows onto the land. Once a tsunami hits land it loses about 1m of height for every 300m it travels inland. Tsunami water will also lose a lot of energy when it crosses the Wairakei Stream. The top of the high ground sits at least 3m above the highest predicted water level. It is designed to survive an earthquake, liquefaction, and scouring from tsunami water.

As extensive development has occurred in Pāpāmoa East more recent modelling was done to capture the new landform.

Some areas have now reduced in boundaries, with far Pāpāmoa East no longer within an evacuation zone boundary. Previous models forecasted what the developed landform would look like, reducing ground elevation to account for predicted developments across Pāpāmoa. As the land has now been earth-worked, and most developments completed, we have greater confidence in final elevations and can now identify these as not being flooded.

Science is always improving with new modelling techniques and more accurate analysis.

Tsunami evacuation zones maps can be found on our webpage. These tsunami evacuation zone maps and signs around Tauranga will be updated in early 2026 based on the updated tsunami inundation data council received from the Bay of Plenty Regional Council in October 2025.

We encourage community to regularly review their evacuation zones to incorporate any changes and replan their evacuation route if needed.

A long or strong earthquake is the natural warning for a tsunami. If you feel an earthquake that is longer than a minute or strong enough that it’s hard to stand up, evacuate as soon as the shaking stops. Do not wait for an official warning as a tsunami wave could reach our coastline within 40 minutes.

If an earthquake occurs further away we may not feel it. If there is a tsunami threat to New Zealand, the national warning will be issued and Emergency Management Bay of Plenty can provide alerts and information on areas, if any, that need to be evacuated. This can be done through Emergency Mobile Alerts, radio, TV broadcasts, social media, and local council websites.

If an earthquake is ‘Long or Strong: Get Gone’. Don’t wait for an official warning; it may be too late. Have a plan, know your plan, practice your plan – including your evacuation route. Now is a good time to develop your household’s evacuation plan and evacuation route to reach your nearest tsunami safe area if you have not already. We will be producing new evacuation maps in early 2026, which will be useful for updating your household’s evacuation plan and route. More help and advice can be found at getready.govt.nz/emergency/tsunami.

Walk, run or cycle if you can. The time it takes to reach a location which is outside the evacuation zone is modelled on an average walking pace. The evacuation maps previously provided, and due to be updated in early 2026, show areas outside of the blue inundation zone that can be reached by foot from most parts of the coast within sufficient time. Trying to reach a location outside of the evacuation zone by car will quickly result in a traffic jam. More help and advice can be found at getready.govt.nz/emergency/tsunami.

With less than an hour after a major earthquake before a tsunami arrives, emergency services will not be able to get you out in time. Make sure you and your family know the evacuation route to your nearest safe location. Discuss evacuation with your neighbours, especially if you know they will need help getting to a safe location. If you live in a retirement village or gated community, make sure you know what the emergency plan is.

Tsunami can arrive in several waves over a long period of time, and this is why you need an emergency pack or grab bag. Include anything you think you will need, like medicine, food and a water bottle. You should be prepared to wait for several hours before the water subsides. More help and advice can be found at getready.govt.nz/emergency/tsunami.