Nelson Tasman Civil Defence

Frequently Asked Questions

  1. Tsunami Evacuation Maps
  2. Frequently Asked Questions

Where can I view the evacuation maps?

You can see the evacuation maps here. You can also see PDFs for download.

Why is this being done now?

These maps have been developed according to national models developed by GNS. GNS completed a study in 2014 which was jointly commissioned by Nelson City Council and Tasman District Council. The report can be found at http://nelsontasmancivildefence.co.nz/. These evacuation maps are not only being produced in our region. They are being published by Civil Defence Emergency Management (CDEM) groups around the country for their respective regions.  These maps identify risk areas and explain evacuation zones in the event of a tsunami.

What does this mean? 

Tasman Bay and Golden Bay are subject to tsunami hazard from various local, regional and distant sources. There are three evacuation zones. “Evacuation zone” refers to areas that could be inundated with water.  These zones are based on inundation modelling for the different tsunami sizes. Red Zone - small more frequent tsunami that are essentially a beach and nearshore hazard.  The Red Zone is also the area of greatest impact in a larger tsunami. Orange Zone - large distant source tsunami (approximately 1 in 500 year event). Yellow Zone - large, but very infrequent, local sourced tsunami (approximately 1 in 2500 year event). If your property is not within one of these zones, your property is not within any known tsunami evacuation zone.

How does it affect the value of my property?

All of New Zealand’s coast is subject to tsunami hazard.  The evacuation maps are intended to identify risk areas and explain the ideal evacuation zones in the event of a tsunami only. They will assist Nelson Tasman CDEM to work with local communities to identify evacuation routes, signage and public alerting options going forward. They are intended to act as a guide for residents of what areas could be affected should there be a threat of tsunami and are for information only. They are not intended to inform property values.

Will this go on my LIM (Land Information Memorandum)?

The maps were created by Councils for operational and public safety purposes, to support a Civil Defence response. The level of analysis used is not sufficiently detailed to use on LIMs. The evacuation zones refer to events with low probability eg 1:2500 and 1:500 year events. So, there are no planning policies or rules proposed to be attached to the evacuation zones – they are for public safety.

Nelson City Council does not propose to put any information related to these tsunami evacuation zones on LIMs. 

Tasman District Council (TDC) proposes that LIMs will not note whether a property is located within a particular evacuation zone.  All TDC LIMs include an Emergency Management section that notes that the Council jointly provides Civil Defence arrangements with Nelson City Council.

What does it mean for my house and contents insurance?

Nelson Tasman Civil Defence and Emergency Management does not have specific information about your private house insurance. We recommend contacting your insurer and/or the Earthquake Commission to find out more. There is more information on the EQC website http://www.eqc.govt.nz/.

How will I be notified that a tsunami is on the way?

If you feel a long (more than a minute) or strong (hard to stand up) earthquake, and you are in a tsunami hazard zone, immediately get out of all tsunami evacuation zones. The earthquake will be the primary natural warning of a tsunami. 

If there is an official warning from Civil Defence (in Nelson Tasman this includes media and social media alerts), then evacuate from the zones (red, orange or yellow) stated in the warning.   

What are the warnings for a tsunami?

Natural warnings of a tsunami include:

  • Strong earthquake shaking (i.e. it is hard to stand up or walk steadily, there is significant household contents damage and building damage)
  • Weak, rolling earthquake shaking of unusually long duration (i.e. a minute or more)
  • Out of ordinary sea behaviour, such as unusual and sudden sea level fall or rise
  • The sea making loud and unusual noises, especially roaring like a jet engine

If there is time, an official warning will be issued:

  • The Ministry of Civil Defence and Emergency Management issues official tsunami alerts for New Zealand
  • The Nelson Tasman CDEM Group will relay these warnings and add local information
  • To be informed, listen to radio/TV, and follow social media
  • If you become aware of an urgent tsunami alert, please tell your neighbours.  Think about vulnerable people you may know such as elderly or disabled people.
  • New Zealand does not have a siren network for tsunami alerts.  Sirens are used only in some places in NZ (mainly eastern coastline locations).

Why don’t we use sirens?

We don’t believe sirens are well suited to our risk profile.  There are a range of alerting options, all of which have pros and cons. Sirens are regarded as less effective and more expensive than other options, such as modern communication tools.  Sirens are not needed for distant source events (we have plenty of time).  For events closer to home, we don’t want people to “wait for the siren”:  if you feel the long or strong earthquake, you need to evacuate all zones.  We are currently working with Red Cross to adopt a new national alerting app for smart phones that will pass on tsunami alerts to the public. 

Where do I go in the event of a tsunami?

In the event of an evacuation, immediately head inland until you are well outside of the evacuation zone.

For people in main urban areas:  if you don’t need your car, go by foot or by bike.  We need to avoid clogging roads with lots of cars.

Don’t stop at the edge of the evacuation zone, keep moving inland so that there is room for others following.

Listen for the official “all clear” on radio and social media.  

What happens after these maps have been released?

tsunami sign postOnce we have completed discussing the evacuation maps with the community, as part of the public meetings in May 2016, we will begin phase two which will include looking into public information boards and, where needed, signage.  We’re interested in the public’s feedback about what would make best sense in our coastal communities.  In some parts of New Zealand there are signs on lamp posts and information boards like the examples shown here.

tsunami sign fence

Why is the water all coloured red on the evacuation maps? 

The coastal area is the red zone, which is likely to be small more frequent tsunami that are a threat on the beach and near the shore.  The water is shown as red because we want people on the water to be aware that these near shore areas can be at risk of tsunami surges and unusual currents. 

Have we had tsunamis before?

Yes, there has been 10-14 tsunami in Tasman Bay and Golden Bay since written records in the mid 1880s. Historical research has shown there was no sign of damage or threat to life.

What is our local tsunami risk?

All of New Zealand’s coast is subject to tsunami hazard.  The greatest hazard is on the east coast of both the North and South Islands as these are directly exposed to greater number of tsunami sources.  Tasman and Golden bays are located on the northern coast of the South Island and open into the South Taranaki Bight.  A tsunami approaching New Zealand from the east will still make its way through Cook Strait to Tasman and Golden bays but its size will be diminished.

Tasman and Golden bays are subject to tsunami hazard from various local, regional and distant sources.  Local sources are where a tsunami will arrive onshore within one hour.   Regional sources are tsunami with a one to three hour travel time and distant tsunami have travel times greater than three hours.

Local sources that could impact Tasman and Golden bays include the offshore extension of the Waimea Fault and other undersea faults in the Taranaki Bight and Cook Strait.

Regional sources include the Hikurangi and Puysegur trenches and offshore faults of Wellington and Marlborough

Distant sources include tectonic subduction zones around the Pacific rim from south America through Alaska and Japan to the New Hebrides and Solomon Islands.  The Kermedec/Tonga trench, although closer than the Pacific rim, is also a distance source of tsunami for Tasman and Golden bays. 

Further information