Scientists have discovered a film of molten magma under the central North Island, dispelling old ideas about the workings of the fiery region. As a result of the find, monitoring of the potentially explosive Taupo Volcanic Zone, the scene of enormous eruptions in the past, will be improved. It was thought magma lurked in unconnected pockets under volcanoes and geothermal zones, said Hugh Bibby of GNS Science. But new measurements have revealed the molten rock lies across a zone 50 kilometres wide and 160km long, northeast of Taupo.
At least five volcanoes in Auckland were born together and the city remains at risk of further simultaneous eruptions, according to a study released today. The Auckland University results showed that the volcanoes of Puketutu, Crater Hill, Wiri, Mt Richmond and Taylor Hill all erupted within 50 to 100 years of each other, possibly at the same time. The research further suggested that Auckland and some other major cities could be at risk of future simultaneous multiple eruptions.
Scientists drilling into the Orakei Basin in Auckland have found the Orakei volcano is probably three times as old as previously thought. A group of geologists from government-owned research and consultancy company GNS Science and the University of Auckland have been drilling into the basin from a barge this week to find out more about the volcanic history of the upper North Island. They have drilled 81m into the sediment beneath the basin and identified ash layers from 90 eruptions in about the past 90,000 years. Project leader Graham Leonard, a volcanologist from GNS Science, said eight of the ash layers were more than 10cm thick. Seven of the thick layers originated from the Auckland Volcanic Field and the other was from the Lake Rotoiti area in the Bay of Plenty. Other ash layers had come from eruptions from volcanoes such as Mayor Island, Taupo Volcanic Zone, Mt Tongariro, and Mt Taranaki. Until now, scientists believed the Orakei volcano was about 20,000 years old. The scientists have identified at least 50 different ash layers from the Auckland Volcanic Field. The thicker layers may have come from close volcanoes such as Little Rangitoto, Mt Hobson, The Domain, Mt St John, and One Tree Hill. The Orakei drill core, together with recent drilling projects in the Auckland area, promises to significantly improve the understanding of the frequency, size, and styles of eruptions from the Auckland Volcanic Field and the upper North Island. This will help the Auckland community prepare for the next eruption in Auckland. The researchers are part of the newly formed ‘Auckland: It’s Our Volcano’ research consortium, which includes a range of research, local government, and emergency management agencies. The project, called the Auckland Maar Volcano Drilling Programme, was started in 1999 and now operates as a partnership between the University of Auckland and GNS Science. The project has collected drill cores from six sites including St Heliers, Onehunga, and The Domain. The initial focus of this work was to provide a comprehensive record of climatic changes over time, but the recovered drill cores also provide a detailed record of past eruptions. The project is funded by the Foundation for Research Science and Technology.