Tsunami Frequently Asked Questions

Tsunami are large and powerful ocean waves that can grow in size as they reach the shore. Some tsunami have been known to travel for thousands of kilometres across the ocean and travel at speeds of up to 800km per hour. 

The most common cause is a sea floor earthquake. Other triggers are under sea landslides, under sea volcanic eruptions, and meteorite impact. Sudden changes to the sea floor cause the ocean to flow away from the disturbance, creating waves. To find out more about tsunami see GNS Science. 

There is an online map where you can search your address. You can also view pdf maps and print and keep them as part of your emergency plan. We recommend knowing where your zones are for home, work, schools, sports grounds or other places you regularly visit. 

Many areas across the Wellington region have a blue line painted across roads and footpaths which show the safe places to evacuate to if there is a long or strong earthquake. The blue lines show the maximum possible run-up heights (worst case scenario) and are based on scientific modelling by GNS Science and Greater Wellington Regional Council. The Tsunami Blue Lines are not in all parts of the region. 

1. If you feel an earthquake that is either Long (longer than a minute) OR Strong (strong enough that it’s hard to stand up), evacuate immediately after the shaking stops. Do not wait for an official warning. The earthquake is your warning that there could be a tsunami. Get to the nearest high ground, or as far inland as possible. 
2. If a national warning has been issued and you are told to evacuate by authorities. 

After a long or strong earthquake a tsunami may reach Wellington in as little as 10 minutes. We recommend evacuating out of all tsunami zones (red, orange and yellow) rather than staying in your building.

For further information see WREMO’s statement about Vertical Evacuation.

For information on what to do if you live in a high-rise building, click here.

A long or strong earthquake is the natural warning for a tsunami - If you feel an earthquake that is long OR strong, evacuate as soon as the shaking stops. Do not wait for an official warning.

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

If you FEEL an earthquake that is either longer than a minute OR strong enough that it’s hard to stand up, this could be big enough to cause a tsunami that reaches Wellington region shores within 10 minutes.

In a big earthquake like this it is likely that communications and infrastructure will be damaged and will not work. People need to know that a long or strong earthquake is your natural warning that there could be a tsunami generated and evacuate immediately without being told.

Walk, run, or cycle if you can.

Vehicles should only be used by emergency services and those with mobility impairments. For those who can't walk or cycle, such as those with mobility impairments, driving is their only option, and you could be preventing them from evacuating safely.

If you need help evacuating or know someone that does, have a conversation with your neighbours about how everyone can get out safely. 

A local-source tsunami is one that has been generated by an earthquake in or near New Zealand. In this case, we feel the earthquake. If this earthquake is either long or strong, it is our natural warning that a tsunami could have been generated and you must evacuate immediately after the shaking stops if you are in a tsunami zone. This type of tsunami could arrive in as little as 10 minutes. 

A distant-source tsunami is one that has been generated from an earthquake that has occurred away from New Zealand, such as in the Pacific Islands, or off the coast of South America. If the earthquake occurs near the Pacific Islands, the travel time to New Zealand is 1 to 3 hours. If the earthquake occurs off the coast of South America, the travel time to New Zealand is up to 12 hours. 

Evacuate to the nearest high ground or as far inland as possible outside the tsunami zones, past the blue lines if your district has them. Identify your quickest route to get out of the zone by looking at the tsunami zone maps, and remember to practise your evacuation so you know where to go. 

See information on why we don't have tsunami sirens, here.

The sirens you hear could be the Volunteer Fire Stations alerting volunteers that there is a fire to respond to. Lower Hutt has flood sirens which were installed in the 1970’s for flood warnings, not tsunamis. The sirens are in flood areas, not in tsunami risk areas – for example there are sirens in Manor Park and Wainuiomata, which are not in any tsunami evacuation zone. These won't be used for tsunami. 

Listen to the news and radio and follow WREMO on Facebook and Twitter. Updates will also go on this website and local council websites. 
WREMO Facebook: @WREMOnz 
WREMO Twitter: @WREMOinfo 

Emergency Mobile Alerts are messages sent by authorised emergency agencies, to mobile phones. The alerts are designed to keep people safe and are broadcast to all capable phones from targeted cell towers. The alerts can be targeted to areas affected by serious hazards and will only be sent when there is a serious threat to life, health, or property, and, in some cases, for test purposes. To find out more click here.