Assessing the chance of an Auckland volcanic eruption and its cost

• There is a 10% chance of an Auckland volcanic eruption in the next 50 years.
• Emergency Management Minister Mark Mitchell outlined priorities for new legislation, including improving co-operation with Māori.
• The document proposes Māori representation in emergency management and using electronic signatures for declarations.

There is a 10% chance of Auckland suffering a volcanic eruption in the next 50 years and it could cost as much as $65 billion in building damage alone.

The disaster scenario is one of several listed in a discussion document designed to inform the Government’s changes to the country’s emergency management legislation.

Consultation is now open until May 13 on how the Government could strengthen emergency management powers following the lessons learned after Cyclone Gabrielle and the Auckland Anniversary floods in 2023.

Emergency Management Minister Mark Mitchell today outlined what his priorities would be in a new bill that would be passed before the next election, including establishing authority during an emergency, improving co-operation with Māori and reducing disruption to essential services.

After the events of 2023, the need for modern legislation was widely acknowledged amid the increasing likelihood of more damaging natural disasters.

The discussion document, released today, clearly made the same point by estimating a 97% probability New Zealand would experience a “natural hazard event” that caused more than $10b in damage.

Cyclone Gabrielle caused widespread damage across the East Coast. Photo / George Heard

It gave several examples, including the possibility of an Auckland volcanic eruption. It estimated there was a 10% chance an eruption would occur in the next half-century and result in a price tag of between $5b-$65b in building and infrastructure losses alone.

Those figures were drawn from Mitchell’s first briefing upon becoming Emergency Management Minister, which listed the “potential full evacuation of Auckland City, with only days to week’s warning” as a likely consequence.

An eye-watering $144b cost had been predicted should a magnitude 9.1 Hikurangi subduction zone earthquake and subsequent tsunami take place. There was a 1% chance such an event would happen in the next 50 years.

Other modelled disasters included an Alpine Fault magnitude 8 earthquake (75% chance, $10b), a large Taranaki eruption (1%, $10b-$15b) and a Hutt River flood (5%, $5b-$10b).

The bulk of the document contained proposed legislative and non-legislative improvements to the current settings, responding to problems highlighted in the response to the 2023 events.

One common finding across the myriad of reviews was the emergency management system’s inability to sufficiently coordinate with iwi Māori organisations, which provided “some of the most effective and efficient responses” in 2023, the discussion document read.

Acknowledging the inclusion of Māori organisations in emergency management planning was “non-existent” in some regions, one of the document’s proposals was to require Māori representation in local emergency management groups.

It noted this proposal risked an “inappropriate” allocation of power to people who were unelected representatives.

Another proposed change was to establish a national Māori emergency management advisory group.

The lack of protection from civil liability in the current legislation was also traversed. The document cited fears the lack of protection could deter people from acting to save lives if it meant they could cause damage to other people’s property and be held responsible.

One potential option was to legislate compensation for labour costs, however, this risked “unpredictable costs” for central and local government.

One of the more unique issues highlighted was the current need for state of emergency declarations to be made by “completing a form with a hand-written signature”.

The document cited feedback from a review of Hawke’s Bay’s response to Cyclone Gabrielle where a respondent deemed the requirement “farcical and dangerous”, citing the “epic feats” emergency management staff needed to achieve to deliver a paper for the mayor to sign during the height of the storm.

The authors proposed enabling the use of electronic signatures or bestowing the ability to do it verbally. Both came with risks, including security concerns.

Adam Pearse is the Deputy Political Editor and part of the NZ Herald’s Press Gallery team based at Parliament in Wellington. He has worked for NZME since 2018, reporting for the Northern Advocate in Whangārei and the Herald in Auckland.