What to do in an emergency

The extent of what we might need to deal with and the consequences from the event might vary but our preparedness to handle the situation may be increased if we have better knowledge and understanding of the event.

Local source tsunami

The chances of a local source tsunami being generated by an earthquake in Pegasus Bay are low. This risk has not changed as a result of the recent earthquakes.

It is still important to know what to do if one does happen as there will be no time to issue an official warning.

Warning signs

Natural signs may be your only warning. Be ready to act if you are at the coast or within two blocks of the coast and experience any of the following:

  • Feel strong ground shaking that makes it hard to stand up;
  • See a sudden rise or fall in sea level;
  • Hear loud and unusual noises from the sea.

What to do

If you are on the beach or within two blocks of the coast, estuary or a river mouth and feel strong ground shaking that makes it hard to stand up:

  • Move quickly inland or at least two blocks away from the coast, estuary or river mouth or to higher ground  (at least four metres high). Use the safest route that you can. Within those first two blocks every step that you move inland or up hill, the safer you will be.
  • If you can't quickly and safely get away from the coast, estuary or river mouth within five minutes (e.g. if you are in Southshore) then consider moving to the upper storey of a multi-storey building, or to the nearest high dune. You should aim to be at least four metres above sea level if you are still within two blocks of the coast. It is unlikely the water from a tsunami in Pegasus Bay would go higher than this.
  • Only use your car if you have to. If you are at all able, evacuate on foot or by bicycle to avoid traffic jams. You are much more likely to get out if you are on foot or on a bicycle and you will leave more room on the road for those people who must use a car.
  • Work out the best route to use from where you are located.
  • Be aware that if the ground shaking is strong, there may be unstable cliffs and rockfall in hillside suburbs.
  • Think about weather conditions.
  • It is your responsibility to determine the best place for you and those with you to move to.

Regional source tsunami

A regional source tsunami may come from the east and north of the North Island or from off the Fiordland coast. It is unlikely to be large, but it may flood low-lying areas.

The most likely regional tsunami source is the Hikurangi subduction zone off the Wairarapa/Hawke’s Bay coastline. Earthquakes are thought to occur here every few thousand years but the timing of the last earthquake in this area is not known. A tsunami from this fault would take between one to two hours to reach the Christchurch and Banks Peninsula coast.

Sea heights above normal tide height at the coast would probably be between one to two metres, but could be higher than this in some localised areas because of the way tsunamis slosh around in Pegasus Bay.

Warnings

It is likely that there will be time to sound the tsunami warning sirens for a tsunami generated in the Hikurangi subduction zone. However, the most important warning will be the natural warning signs.

Be ready to act if you are at the coast or within two blocks of the coast and experience any of the following:

  • Feel a moderate, rolling earthquake that lasts for a minute or more.
  • See a sudden rise or fall in sea level.
  • Hear loud and unusual noises from the sea.

If you have concerns, do not wait for an official warning or for the sirens to sound. Evacuate if you feel it is the safest thing to do.

What to do

If you are on the beach or within two blocks of the coast, estuary or a river mouth and feel a moderate rolling earthquake that lasts a minute or more:

  • Move quickly inland or at least two blocks away from the coast, estuary or river mouth or to higher ground  (at least four metres high). Use the safest route that you can. Within those first two blocks every step that you move inland or up hill, the safer you will be.
  • You should aim to be at least four metres above sea level if you are still within two blocks of the coast.  It is unlikely the water from a tsunami in Pegasus Bay would go higher than this.
  • Only use your car if you have to.
  • You will need to use commonsense to work out the best route to use from where you are located.
  • Be aware that if the ground shaking is strong, there may be unstable cliffs and rockfall in hillside suburbs. Think about weather conditions.
  • It is your responsibility to determine the best place for you and those with you to move to.

Distant source tsunami

The most likely tsunami to impact on coastal Christchurch and Banks Peninsula is one generated off the coast of South America or Alaska. Distant source tsunamis are unlikely to be greater than five metres above normal sea level on arrival at the coast.

Historically, all damaging tsunamis to affect coastal Christchurch and Banks Peninsula have been generated by earthquakes off the coast of South America – in 1868, 1877, 1960, and most recently in February 2010.

A tsunami generated off the coast of South America will take between 12 to 15 hours to reach the Christchurch and Banks Peninsula coastline.

The areas most at risk from distant source tsunamis are coastal areas from Brooklands/Kainga to Sumner, and low-lying areas of Banks Peninsula. Tsunami wave heights are likely to be higher in the bays and harbours of Banks Peninsula than on the Pegasus Bay coastline due to the funnelling affect of the narrow inlets.

In the event of a distant source tsunami being generated, there will be time to issue an official warning, and the tsunami warning sirens will be activated.

Warnings

Official warnings will be issued on radio and television. It is important you listen for local information in these messages, as the forecast tsunami effects will vary along different parts of the New Zealand coastline.

The tsunami warning sirens will be sounded if scientific and technical experts, emergency services and Christchurch City Council officials are of the opinion that public safety is threatened.

You may also receive a tsunami warning through an unofficial source, such as from friends, family, social media sites or international media reports.


What to do

If you receive an unofficial warning - verify this information if possible.

Listen to local radio stations for official warning information:

  • Classic Hits (97.7FM)
  • National Radio (101.7FM or 675AM)
  • Newstalk ZB (1098AM)
  • More FM (92.1FM)
  • Radio Live (99.3FM or 738 AM)
  • The Breeze (94.5FM)

Confirmation of official warnings will come from Christchurch City Council(external link)Canterbury CDEM Group(external link)Ministry of Civil Defence Emergency Management(external link)GeoNet(external link).

Evacuating

NZ Police and Christchurch City Council have identified 19 sectors within the Christchurch coastline which will be the focus of any evacuation activity. About 23,000 people in 8570 households will be involved in a total evacuation of the zone.

Arrangements are in place that all available NZ Police, Fire Service, Council Park Rangers and Response Team personnel, and Canterbury Civil Defence Emergency Management Group Response Team personnel would start to evacuate residents from the identified sectors.

If you are requested to evacuate, follow the instructions of emergency services and/or Civil Defence personnel:

  • Move to a safe area outside the Coastal Evacuation area – to friends or family or to the alternative location identified in your own emergency plan
  • You can evacuate to higher ground (e.g. Mt. Pleasant Road, Evans Pass Road, Summit Road) – at least 15m above sea level is recommended
  • Do not return until you are told it is safe to do so.

Evacuation routes

evacuation route map

The coastal evacuation map identifies preferred routes leading out of evacuation sectors.

If you are required to evacuate, take the route closest to your home or workplace (follow the direction of emergency services personnel).

  • Harbour Road - Kainga Road - Marshlands Road (Kainga)
  • Spencerville Road -  Marshlands Road (Spencerville)
  • Lower Styx Road -  Marshlands Road (Styx)
  • Beach Road - Mairehau Road (Northshore)
  • Bowhill Road - Travis Road (North New Brighton)
  • Lonsdale - Keyes - Rookwood - Travis (North New Brighton)
  • Seaview Terrace - Pages Road (New Brighton)
  • Bridge Street - Breezes Road (South New Brighton)
  • Bridge Street - Dyers Road - Linwood Avenue (Southshore)
  • Rocking Horse Road - Estuary Road - Bridge St (Southshore)
  • Main Road - Ferry Road (Redcliffs, Sumner)
  • Wakefield Avenue - Evans Pass Road - Summit Road (Sumner)
  • Ferry Road or Hargreaves Road (Ferrymead)
  • Bridle Path Road - Tunnel Road (Heathcote Valley)

Cordons will be set-up by the Police and the Council’s roading contractors at key points to:

  • prevent members of the public entering the evacuated area;
  • assist traffic flow out of the area and facilitate emergency services entering when required.

Cordons will be maintained until it is safe for people to re-enter the evacuation area.

Earthquake

Earthquakes strike suddenly, violently, and without warning at any time. Knowing what to do during an earthquake can help protect you and your property.