Investigating volcanoes – introduction
Volcanoes are exciting. They can erupt spectacularly, throwing molten rock into the air in pyrotechnic displays that are simply stunning. Did you know that one of the most violent eruptions in the world over the last 5,000 years was in New Zealand where Lake Taupō now lies? In fact, 26,000 years ago Taupō exploded in a much greater eruption to devastate much of the central North Island and form an immense hole in the ground that is now filled by Lake Taupo.
Mt Ruapehu
Mt Ruapehu in the central North Island remains an active volcano. On 17 June 1996, Mount Ruapehu erupted, sending ash into the sky.
We have examples of many types of volcanoes in New Zealand. We have dormant volcanoes (Taranaki, Taupō), active volcanoes (White Island, Mt Ruapehu) and areas where the earth boils and hisses steam as a result of past volcanic activity (Rotorua). Our biggest city – Auckland – is built on a volcanic field.
There are also many volcanoes in the Pacific, including the very large Hunga Tonga–Hunga Haʻapa underwater one. Read about the devastating Hunga Tonga–Hunga Haʻapa volcanic eruption in January 2022 and what we might expect next. This article looks at what we have learnt a year later about this violent eruption and predicting future submarine volcanic eruptions.
But what do we really know about volcanoes? Luckily, we have some of the best scientists in the world finding answers. Meet four New Zealand scientists who tell us about the volcanoes they have studied and take us on a tour of our local volcanoes and their explosive history.
Meet our scientists
It may come as a surprise that volcanoes don’t have a defined magma chamber. Professor Richard Price at the University of Waikato has been studying Mt Ruapehu and Mt Taranaki, and his research proposes a new model for magma occurrences beneath volcanoes – with crystal mushes and percolating magma but no defined magma chamber.
Associate Professor Darren Gravley at the University of Canterbury has discovered two massive caldera eruptions that occurred within just days of each other. One of these eruptions formed Lake Rotorua. Ōhakuri exploded only 30 kilometres away and just days later. This is a remarkable finding. Normally these large caldera eruptions happen on average only every 50,000 years. So why were these events so closely linked? Is this event special to New Zealand? Could it happen again?
Maungawhau (Mt Eden)
Mt Eden is a scoria cone volcano that last erupted around 16,000 years ago. At 196 m in height, Mt Eden is the highest natural point in Auckland. Historically used as a pā site and also a quarry.
Acknowledgement: Lloyd Homer, GNS Science
Professor Jan Lindsay works at The University of Auckland. Her job is to predict where and when an eruption could occur in Auckland – and what we could do if it did. Her science could save the lives and protect the businesses of thousands of people. Some would say that the developers in Auckland got it very wrong. The country’s biggest city, home to more than 1.3 million people, is built on an active volcanic zone. Unlike Taupō, which straddles an area where two tectonic plates are colliding, Auckland city sits on a volcanic field. This hot spot throws up a new volcano every couple of thousand years. While the eruptions are smaller than those at Taupō, they could happen at any time right in someone’s backyard.
Helping and supporting this research is Associate Professor Phil Shane at The University of Auckland. He looks at rock core samples – drilled sections from the bottom of lakes and swamps that preserve the geological history. Dr Shane can look back into the past, up to 60,000 years ago or more, and see what was happening in Auckland and in New Zealand. He can track which volcano exploded, when and how violently.
Explore our volcano content to understand our past and help us prepare for a future living with active volcanoes.
Take up the challenge
Student activities range from hands-on to screen-based interactives. Students can make a caldera in the sandpit or make a model cinder cone – both demonstrate volcanic formation and shape. Making lava fudge is a tasty demonstration of three different types of volcanic rocks. Rocks also feature in Lost – a hot rock and Identifying volcanic rocks. Continue hands-on observations by growing crystals or taking core samples.
Go on a volcano hunt, which covers the length of Aoteaora. Then discover how scientists and others help us stay safe in these shaky isles with the activities Watching Rangitoto erupt, Who's on your team? and Home disaster kit.
Question bank
The Investigating volcanoes – question bank provides an initial list of questions about volcanoes and places where their answers can be found. The questions support an inquiry approach.
Key terms
For explanations of key concepts, see Investigating volcanoes – key terms.
Timeline
Explore the timeline to look at some historical aspects of volcanoes in New Zealand.
Planning pathways
Realistic contexts connect students to authentic scientific processes and purposes. It’s all explained in Volcanoes resources – planning pathways.
Useful link
This article from The Conversation looks at how volcanoes influence climate and how their emissions compare to what we produce.
