Common questions on tsunami maps

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).

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 35 40 minutes. 

If you are near the coast and experience any of the following, take action. Do not wait for official warnings. 

• See a sudden rise or fall in sea level 
• Hear loud or unusual noises from the sea 
• Feel a strong earthquake that makes it hard to stand or a long earthquake that lasts more than a minute 

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. 

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.  

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. 

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 landslide-generated tsunami from White Island is unlikely to overtop the dunes, although some water could surge through cuts in the dune or low-lying areas.  

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. 

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 and practice your household’s evacuation plan and evacuation route to reach your nearest tsunami safe area. Our new tsunami evacuation maps will be useful for updating your household’s evacuation plan and route. More help and advice can be found 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 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 atgetready.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, or even days, before the water subsides. More help and advice can be found at getready.govt.nz/emergency/tsunami.

Our dune system is an excellent first line of defence against 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. 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 8 metres, so when a 14 metre wave hits the dunes, only the top 6 metres of the wave flows onto the land. Once a tsunami hits land, it loses about 1 metre of height for every 300 metres it travels inland. Tsunami water will also lose a lot of energy when it crosses the Wairakei Stream. The top of the high ground at Gordon Spratt Reserve sits at least 3 metres 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. Pāpāmoa East is now showing a greater extent of inundation, so it is important you check your new evacuation zone map and plan your route to reach a safe location should a tsunami occur. 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.

Property values are influenced by many factors and are determined by the real estate market. While tsunami risk mapping and tsunami evacuation zone maps 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.

Updated tsunami inundation data was provided to Tauranga City Council and shared with affected property owners in late 2025. It is a requirement for Council to share new hazard data when it becomes available.

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 process to incorporate inundation data in evacuation maps is now complete, and new tsunami evacuation maps have been made available to the public.

Research associated with data that’s used in the new tsunami evacuation zone maps was undertaken by GNS (Earth Sciences New Zealand) with peer reviewing by NIWA (National Institute of Water and Atmospheric Research).

The new modelling is also based on a one in 2500 years 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.

Tsunami evacuation zone maps are public guides to assist the community in where to evacuate to, or which areas to remove themselves from, should a tsunami occur. The evacuation zone maps are publicly available and do not form part of the official information held on individual property files. The maps may appear in a LIM as discretionary information relating to a natural hazard.

If you received a letter in late 2025 advising that your property is located within a tsunami inundation zone, that information will appear in both your property file and in a LIM. It will not appear on a property title. .