Volcanic response planning in areas of distributed volcanism: An Auckland case study

With 1.7 million people, Tāmaki Makaurau (Auckland) is the largest city in New Zealand. It contains a third of the national population and is responsible for 38% of the national GDP. The city is situated around the remnants of the 53 volcanic centres of the Auckland Volcanic Field. The boundaries of the Auckland Volcanic Field encompass the central business district and central suburbs, the main port, airport and nationally important transportation and lifeline utility routes and assets. This makes any future eruption in the Auckland Volcanic Field a high risk, not only for the resident population, but also the country, even if the likelihood of an eruption is low.

Developing a multi-agency volcanic response plan is essential to ensure any future eruption, an event that has never been experienced in recorded history, is met with a unified response. The Auckland Civil Defence and Emergency Management (CDEM) Group is responsible for coordinating emergency management and inter- agency planning activities for key hazards in the region, including volcanic hazards. Volcanic response planning in the Auckland Volcanic Field is complicated by the high degree of uncertainty. This uncertainty extends from whether unrest may result in eruption, through to the location of future vents and timeframes of magma ascent and eruption processes. Identifying response activities by eruptive phase and agreeing critical actions for response functions (e.g., movement of people, emergency welfare, command and control, health) allows for a ‘lift and shift’ plan that can be implemented wherever the next eruption occurs.