Published: 07 Nov 2022
Timaru District Council is releasing revised tsunami evacuation zones today in light of updated tsunami modelling that provides new insights about their likely impacts.
Environment Canterbury commissioned the Institute of Geological and Nuclear Sciences to complete multiple scenario tsunami modelling for the Mid and South Canterbury coastline, as part of a programme of tsunami modelling for the whole Canterbury coast.
The results show that in some parts of Timaru District the existing tsunami evacuation zones can stay the same or be reduced. However, in many places inundation from ‘worst case’ extreme tsunami reaches further inland than the existing evacuation zones and in these areas the zones have been extended.
Team Leader and Emergency Management Advisor, Phill Mackay says Timaru’s tsunami hazard is lower than other parts of New Zealand because there are no known significant tsunami sources off the South Canterbury coast, and the shape of the coast tends not to amplify tsunami waves.
The new red and orange tsunami evacuation zones are similar to the existing red and orange zones. The red zone, which is the area most likely to be affected by a tsunami, includes beaches, lagoons, and river mouths. The orange zone includes low-lying coastal land, which is mostly farmland or commercial and industrial areas, with some small residential areas.
“If you’re in a red or orange zone and you feel an earthquake that is long or strong, get gone,” said Mackay.
“There may not be time for an official warning, so once the shaking stops head immediately inland, out of the red and orange tsunami evacuation zones.”
The most notable change is the creation of new yellow tsunami evacuation zones in more populated areas of the district. These areas are least likely to be affected, but could be flooded in a rare, very large tsunami.
They include over more than properties in Waipopo, Washdyke, Waimataitai, Redruth and Pareora.
Mackay says people in a yellow zone only need to evacuate if they receive an official warning from Civil Defence Emergency Management.
“If you live or own property in Timaru District, I would encourage you to check our online map to see whether your property has been affected by the tsunami evacuation zone changes,’’ says Mackay.
“If you live or work in a tsunami evacuation zone, it is important that you have an evacuation plan and know what to do in case of a tsunami. You need to think about the route you would take to evacuate and where you would go,’’ Mackay says.
Actions people should take:
- People should evacuate the red and orange tsunami evacuation zones, without waiting for an official warning, if they feel a long or strong earthquake. A long earthquake is when the shaking lasts more than a minute and a strong earthquake is when the shaking is so strong it is hard to stand up. It is possible that a tsunami has been generated off the North Island or Fiordland coast that could reach Timaru within 2-3 hours.
- People do not need to evacuate the yellow tsunami evacuation zone after a long or strong earthquake, unless they are told to by Timaru Civil Defence Emergency Management or emergency services.
- For a tsunami that is coming from further away, such as the Pacific Islands or South America, people will be told which zone(s) to evacuate in an official tsunami advisory or warning. In most cases this will just be the red zone (beaches, lagoons and river mouths), but in a larger tsunami it could be the orange and yellow zones as well.
To check which zone you are now in go to the national tsunami evacuation zone map at https://ecan.maps.arcgis.com/apps/Minimalist/index.html?appid=591062afb6b542abb247cc8d15a64855 The site has a search function that allows you to enter a property’s address to see which tsunami evacuation zone it is in. For more local information visit https://www.timaru.govt.nz/tsunami
Last updated: 07 Nov 2022