Auckland Council has updated the region’s tsunami evacuation maps and the new modelling shows the area of Tāmaki Makaurau at risk from damaging tsunami waves is less than previously thought.

Auckland Emergency Management head of operations John Cranfield said the new tsunami wave modelling was more accurate and Aucklanders should check out the Hazard Viewer to help them become familiar with areas predicted to be flooded during a tsunami, as part of being prepared for an emergency.

The new maps cover the entire coastline including the Hauraki Gulf Islands and Aotea Great Barrier Island.

The red zone shows the area needing to be evacuated in a shore and marine tsunami threat, when strong and unusual currents and dangerous surges at the shore are expected. The yellow zone shows the area needing to be evacuated where there is a land tsunami threat, where tsunami flooding is expected to affect inland areas. Photo / AEM

The previous tsunami evacuation zones were divided into three zones. Photo / AEM

Cranfield said the new maps were also simpler to understand.

“The new maps use a two-colour system. The red zone shows the area needing to be evacuated in a shore and marine tsunami threat, when strong and unusual currents and dangerous surges at the shore are expected.

The yellow zone shows the area needing to be evacuated where there is a land tsunami threat, where tsunami flooding is expected to affect inland areas.”

The new mapping uses modelled earthquakes on real fault lines around the Pacific to replicate how tsunami waves are generated and track across the ocean and to our coastline.

The modelling takes into account how islands influence the path of tsunami waves, as well as how landforms on the coast and the shape of the seafloor influence the way tsunami waves behave.

Auckland Council Civil Defence and Emergency Management Committee chairperson Councillor Sharon Stewart said it was pleasing the new evacuation maps show fewer areas at risk from tsunami flooding but said Aucklanders should still be alert to the risk of tsunami threats.

“The new modelling suggests fewer of our coastal communities are expected to be impacted during a damaging tsunami in Tāmaki Makaurau - particularly the areas surrounding the inner Manukau, Kaipara and Waitematā harbours and on the west coast beaches, where impacts are now expected to be confined to shore and marine areas.

“However, areas more exposed to the Pacific Ocean like Aotea Great Barrier Island and Auckland’s north-eastern coastal communities are still at risk of large tsunami, as is anyone that enjoys the beaches and marine areas of the region.

“People need to remain prepared to move quickly in a tsunami emergency.”