Auckland faces mass destruction following a volcanic eruption, according to a new study, with transport networks crippled and a third of the population reduced to refugees.
A startling new University of Canterbury scientific paper released on Tuesday looks at what would happen if there was a two-month-long volcanic eruption near the Mangere Bridge, south of Auckland's CBD.
The volcanic eruption would destroy anything up to two-and-a-half kilometres away.
"In such an eruption, up to 435,000 residents could be displaced, with Auckland's difficult geography limiting transportation and evacuation routes," the authors note.
"We find that most physical damage to transportation networks occurs from pyroclastic surges during the initial stages of the eruption."
However the most extensive transport cuts would be six days before the eruption due to evacuation zones put in place.
The effects of the eruption are compounded by the ash deposits on road and railways, which would continue to disrupt transport for over a month.
"Auckland Airport would not be directly affected by physical damage, but would have restricted access from evacuation zoning and airspace restrictions, forcing limited domestic and cargo flights to redirect to Whenuapai and Ardmore Aerodrome," the study says.
Researchers say the most important factors for keeping the transportation network open are ensuring bottleneck areas are cleared, making sure there is an electricity supply for transport systems, and working to provide fuel supplies.