Auckland Sitting On Active Volcanic Field

November 8, 1999

AUCKLAND SITTING ON ACTIVE VOLCANIC FIELD

New Zealand’s biggest city, Auckland, sits on an active volcanic field that could produce a new volcano at any time, say researchers.

“Scenarios being considered include an eruption forming an offshore island, one in the Tamaki Estuary, and three within 2km of the central business district. Each case is expected to result in the evacuation of 100,000 to 150,000 people and major disruption to commerce and services.” says project co-ordinator David Johnston

An investment of the Public Good Science Fund has enabled scientists to work with the Auckland Regional Council to better understand the field and the hazards posed by such a volcano.

The group from the Institute of Geological and Nuclear Sciences(GNS) has developed five realistic eruption scenarios to illustrate what could happen to Auckland’s population, infrastructure and environment.

“Risk assessment of each scenario has revealed the extent of the social and economic impact on the Auckland community,” says Dr Johnston.

The research has also noted the importance of building relationships among a range of organisations and community agencies representing vulnerable groups.

Dr Johnston says the first of Auckland’s 50 volcanoes started to appear about 140,000 years ago.

“The life of the volcanic field is estimated at one million years so, geologically speaking, the field is still young. There has been a trend to bigger and more frequent eruptions around Auckland in the past 20,000 years. Rangitoto, the youngest and biggest volcano, formed about 600 years ago.”

“The lack of surface activity can lead to the false impression that the Auckland volcanic field is extinct. But the hot spot of magma deep below the city remains active and will almost certainly send up another volcano in the future.”

“ The next eruption is unlikely to occur at an existing volcano. Auckland tends to produce “single episode” volcanoes – after the eruption the volcanic plumbing seals off and blocks the flow of future magma.”

GNS, in partnership with Massey University, is also researching how much people know and understand about the vulnerability of New Zealand to natural hazards. They are also evaluating methods of improving the effectiveness of hazard education programmes.

Further information:

Contact: Dr David Johnston, Ph: 07-374-8211, Email: d.johnston@gns.cri.nz

Patricia Donovan, Foundation for Research, Science and Technology Ph: 04 498 7809, Mobile 025 226 4136

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