Lava flows from Auckland’s volcanoes
Underlying Auckland is a diffuse pool of basalt magma. Magma is molten rock that is formed from the Earth’s mantle. Lava is magma that has reached the Earth’s surface via a volcanic eruption.
Each of the 53 volcanic centres in the Auckland Volcanic Field stems from a separate eruption from the magma pool. It’s unlikely that the magma will push through in the same place twice, so each volcano we see on today’s landscape is probably dormant. However, the underlying magma source itself is still active.
Rhyolite, andesite and basalt
Three types of volcanic rocks.
New Zealand has three main types of volcanoes, and each has been formed from a different type of magma. Once the lava has erupted, it cools and solidifies into different types of volcanic rock:
Basalt magma often forms shield volcanoes.
Andesite magma often forms cone volcanoes.
Rhyolite magma often forms calderas. Depending on how much gas the magma contains, it can also form cone volcanoes.
Lava flows from past eruptions inform experts about what happened tens of thousands of years ago. This information helps them predict when a volcano might erupt and determine what the consequences could be.
Rocks tell a story
How do experts find out what happened such a long time ago? One method involves identifying the age of an eruption by looking at rock core samples. Geologists get the samples by pushing or drilling cylindrically shaped tubes down deep into the ground. When the tubes are pulled out, they contain a core sample of the geological materials below. The colours and width of the various layers can be read like the pages of a book.
Another method is analysing records from boreholes drilled for building foundations, road construction and water supply. This is how the Grafton volcano was ‘rediscovered’ a few years ago.
Homeowners and developers also add to the story. They discover and report approximately one new lava cave in the Auckland Volcanic Field each month!
Lava flows from Auckland volcanoes
The evidence tells us that the Auckland Volcanic Field lava flows were basaltic. Its composition means the lava is hotter and will flow further than most other lava flows. This information helps the DEVORA (DEtermining VOlcanic Risk in Auckland) programme plan for impacts caused by future volcanic activity.
As part of their outreach, the DEVORA team uses infographics to share information about hazards – including those caused by lava flows.
The floor is lava – lava flows from Auckland’s volcanoes
Lava is one of the most widely known volcanic hazards. This infographic looks at the type of lava produced by the Auckland Volcanic Field and some of its potential impacts.
Download the infographic as a PDF.
Using infographics as teaching tools
Science knowledge is often communicated through visual representations – graphs, diagrams and infographics. Each type of visual representation has literacy components that ākonga may need support to understand. The science capability ‘Interpret representations’ encourages ākonga to think about how data is presented, what the representation tells us and how it gets the message across.
Interrogate the infographic with questions – for example:
Who created the infographic?
Who is the intended audience?
What is the central theme?
Are there subthemes?
What makes the message credible?
What other information might you need to understand the infographic?
Are there specific scientific words or terms?
Where can you find the information that might fill in these gaps?
By their nature, infographics use concise text, so we’ve placed each DEVORA infographic within an article that includes background information and links to related content. Use them to explore and deepen understanding of concepts within the infographics.
DEVORA’s suite of infographics:
City of volcanoes – the Auckland Volcanic Field Ngā Tapuwae ō Mataaho supported by the article Tāmaki Makaurau – city of volcanoes.
Hidden eruptions – the search for Auckland’s volcanic past supported by the article The search for Auckland’s volcanic past.
Rangitoto: odd one out – the story of Auckland’s largest volcano supported by the article Rangitoto – Auckland’s largest volcano.
Eruption impacts – how would an eruption in Tāmaki Makaurau impact the city? supported by the article Auckland Volcanic Field – eruption impacts.
The floor is lava – lava flows from Auckland’s volcanoes supported by the article Lava flows from Auckland’s volcanoes.
Ngā maunga – a brief history of maunga (mountains) in the Auckland Volcanic Field supported by the article Ngā maunga – Tāmaki Makaurau Auckland’s volcanic field.
Volcanic gas, acid rain and ash from possible future Auckland Volcanic Field eruptions supported by the article Volcanic gases – impacts on air quality.
Nature of science in the curriculum
Developing visual and numerical literacies such as those used in infographics supports students to analyse and interpret data. The infographics also enable students to engage with science in social and cultural contexts.
Related content and activity ideas
The article Volcanoes resources – planning pathways provides additional pedagogical information. It also includes the interactive Planning pathways using volcano resources, in which we curate resources into key science concepts and topics. This curation has a specific focus on Auckland’s volcanoes.
Explore this timeline to look at some historical aspects of volcanoes in New Zealand.
Try out a few of these activities:
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.
Magma Pop is a virtual game that helps ākonga learn about Earth’s most common minerals and the processes that happen in a magma chamber.
Useful links
Visit the DEVORA website to learn more about its work – including teaching resources and opportunities for free outreach.
The DEVORA team is interested in all aspects of the Auckland Volcanic Field. Visit the Natural Hazards Commission website to read the article Research tackles history and mystery around Auckland lava caves.
Acknowledgement
This resource has been produced with the support of DEVORA (DEtermining VOlcanic Risk in Auckland).
DEtermining VOlcanic Risk in Auckland (DEVORA)
DEtermining VOlcanic Risk in Auckland (DEVORA) is a multi-agency, transdisciplinary, collaborative research programme led by volcanologists at the University of Auckland and Earth Sciences New Zealand (formerly GNS Science) and funded by the Natural Hazards Commission Toka Tū Ake (NHC) and Auckland Council.