Three types of tsunami | Evacuation zones | Tsunami warnings | Get tsunami ready
Tsunami are long, deep, fast travelling ocean waves caused by earthquakes, landslides or volcanic eruptions beneath or near the ocean. They can be spread over a 12 hour period arriving up to an hour apart.
The Kāpiti Coast is a seismically active area and with the coastline running the length of our district, we live with the risk that a large earthquake or a tsunami could affect us at any time.
The risk is slightly greater since the 14 November 2016 Kaikoura earthquake, and while we can’t predict when earthquakes and tsunami will happen, we can help protect ourselves and our families by being prepared.
If you live, work or regularly spend time in one of the Kāpiti Coast’s tsunami evacuation zones it’s important that you know the warning signs of a tsunami and have a plan to get to safety.
The three types of tsunami - how much warning will we have?
Tsunami can be generated locally (e.g. Cook Strait), generated regionally (e.g. Solomon Islands), or generated at a distant source (e.g. South American coast).
Local source (less than one hour)
- Little warning, could arrive on shore within minutes.
- Generally larger in size and has potential for severe impact.
- Residents need to consider the earthquake itself a natural warning, and self evacuate.
Regional source (between one and three hours travel time)
- Limited warning time but enough for evacuation.
- Likely to have time available for official warnings.
Distant source (over three hours travel time)
- Provides warning time for evacuations, and is generally smaller size and lesser impact.
Tsunami evacuation zones
Tsunami Evacuation Zone Maps have been developed by Greater Wellington Regional Council, Kāpiti Coast District Council and Civil Defence, which identify the areas residents need to evacuate from in the event of a tsunami. View tsunami evacuation maps here.
Types of tsunami warnings
If a tsunami is triggered close to the Wellington region, there will be no time for an official warning to be given. If you experience any of the following:
- A strong earthquake (i.e. it's hard to stand up) or
- A weak, rolling earthquake with shaking of unusually long duration (i.e. a minute or more).
- The ocean behaves strangely (unusual noises from the ocean or the ocean rushes in or out).
- Immediately evacuate the red, orange and yellow zones.
- Do not wait for official warnings, as a tsunami may be only minutes away.
We don’t have civil defence sirens in Kāpiti. In a local earthquake that generates a local tsunami, there’s generally no time for official warnings, and sirens are vulnerable to being damaged or rendered unusable due to lack of power.
There may be official warnings issued by Civil Defence Emergency Managment officials from your Council and emergency services. These can include warnings over local radio and television, WREMO or Council social media or websites, or emergency services and Council vehicles using public adress systems to clear the beaches and streets within the vicinity of the beaches.
You should follow official instructions and stay out of any evacuated zones until the official 'all clear' has been given.
Informal warnings could come from friends, family, international media, and the internet. You should verify the warning and follow instructions provided by Civil Defence Emergency Management officials.
Get tsunami ready
Before a tsunami
If you live or intend to live in a tsunami evacuation zone you should:
- Develop a Household Emergency Plan and prepare an Emergency Survival Kit that will help you cope with being isolated for up to seven days (including companion animals).
- Have an evacuation route and test it. Know how far you need to go to get out of the tsunami evacuation zone. Test a mock evacuation, walking inland to the edge of the evacuation zone (keeping an eye out for any useful areas of higher ground as you go). Now you know what it'll take if you need to evacuate.
- Familiarise yourself with evacuation maps in areas you travel to often (eg work and/or school) as well as home.
- If you are buying land or a building in a coastal area, talk to the Council on the risks of a tsunami, coastal storm surge and erosion.
Evacuating from a tsunami zone:
As a rule of thumb, if an earthquake is long or strong, get gone!
- If you feel a long or strong earthquake that lasts longer than a minute or is strong enough to knock you off your feet, and you're in a tsunami evacuation zone, do not wait to be told - evacuate immediately. Stay out of the evacuation zone until you get the all clear.
- If you can, evacuate on foot or by bicycle.
- If you evacuate, it's best to make your way to friends or family outside of the evacuation zone or take direction from your council on the day.
- If you're outside of the tsunami zone, stay put. This will reduce congestion and help those who are at most risk evacuate in time.
After a tsunami:
- Listen to the radio for civil defence advice.
- Don’t go sightseeing.
- Don’t go down to the sea or return to your property until you have been told it is safe to do so.
Kaikoura tsunami November 2016 research