The search for Auckland’s volcanic past
When it comes to volcanoes in the Tāmaki Makaurau Auckland region, understanding the past is key to understanding the future. Researchers from the DEVORA programme study ash layers to learn about past volcanic eruptions and what they can tell us about future eruptions.
Ka mura, ka muri – walking backwards into the future.
Tephra
Tephra is the collective term for all airborne volcanic material ejected during an eruption. Ash is the smallest component of tephra (material less than 2 mm), lapilli is slightly larger (2–64 mm) and the largest fragments are called blocks and bombs (larger than 64 mm). Volcanic ash is made up of tiny, jagged particles of rock, minerals and volcanic glass. Ash is formed when gases carry magma into the air. The explosive nature of the gases breaks the magma into tiny particles, which solidify while airborne.
Explaining a rock core
Dr Phil Shane takes us through a rock core – a sample of rock going back tens of thousands of years that details events such as volcanic eruptions.
Select here for the video transcript and copyright information.
Volcanic ash differs from eruption to eruption due to the minerals present in the magma. Differences in colour, chemistry, quantity and location enable experts to identify where the ash originated. This information creates a history of volcanic activity in the area. Drilling into geological material provides a vertical history of geologic and climate conditions over time.
Drilling for data
One method involves identifying the age of an eruption by looking at rock core samples. Geologists get rock core 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 rocks and sediments below. Scientists are able to see different layers in the cores, and these layers help them determine what volcanic eruptions happened when and where.
DEVORA – assessing volcanic hazards and risks in Auckland
The DEVORA (DEtermining VOlcanic Risk in Auckland) programme was launched in 2008. It gathers data about the Auckland Volcanic Field and studies the deposits of past eruptions to learn more about how and when our volcanoes formed. As part of their outreach, the DEVORA team uses infographics to raise awareness about the Auckland Volcanic Field, how the team gathers data and what the data can tell us.
Hidden eruptions – the search for Auckland’s volcanic past
This infographic fact sheet delves into the layers of volcanic history across the city.
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.
Find out how boreholes enabled geologists to find a volcano hidden beneath the suburb of Grafton, close to the Auckland University Medical School.
Core samples are used in many scientific fields:
Lake sediment cores – exploring the past– clues to the history of lakes in Aotearoa
Hikurangi subduction zone – clues to tectonic plates and earthquakes
Ice ages unearthed – clues to New Zealand’s past
Trapped in ice – clues about the Earth’s climate, past and future
The heartbeat of Antarctica – clues about the sea ice cycle
Activity ideas
The activity Interpreting lake sediment data uses information gained from sediment cores, including Lake Pupuke – Auckland. It includes discussion questions to help students consider how the data was collected and how the information is presented via text and visual representations.
It’s not just scientists that take core samples. Create them with these activities:
Making a core sample – ākonga use a small coring tool and examine the sample for features such as particle size, colour variation and layering.
Investigating the relationship between measured brightness and length of ice cores – ākonga use a potato chip tube to make an ice core to simulate the work of scientists in Antarctica.
Useful links
Visit the DEVORA website to learn more about its work – including teaching resources and opportunities for free outreach.
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.