UC research discovers fresh information about key NZ volcanoes
March 7, 2014
University of Canterbury (UC) has uncovered fresh information about New Zealand’s volcanoes that could be helpful when
volcanoes erupt in future.
Geology researcher Dr Paul Ashwell, with supervision from volcanologist Dr Ben Kennedy, found a host of factors play a
part in how lava domes erupt, including the underlying ground surface and the physical make-up of the lava itself.
Understanding these factors and how they affect the eruption of lava is critical to predicting how a dome will form and
if it will produce block and ash flows.
Dr Ashwell’s thesis investigated lava domes at Mt Tarawera and Mt Ngongotaha, near Rotorua, so he could look how each
dome erupted and what impact it would have had on the surrounding areas.
Mt Tarawera erupted about 700 years ago and rates as the largest eruption in New Zealand since Taupo erupted 1800 years
ago. Tarawera formed three large lava domes at the top of the volcano.
``This eruption was studied by another of my supervisors, Professor Jim Cole, and was an important site for
understanding early concepts of volcanology in the 1960s and 1970s,’’ Dr Ashwell says.
``I built on this work by looking at one of the lava domes, Ruawahia, which is at the summit of Mt Tarawera, in detail
and mapped very small structures such as bubbles and crystals to get an idea as to how each part of the dome erupted.
``I found that Ruawahia may be made up of several smaller domes or flows of lava that together form the dome, but each
forming at a different time. I also found out that the underlying ground surface was a very important feature, as it
dictated how far the lava could move.
``Matt Edwards, an honours student at UC, and myself have mapped the edge of Ruawahia, and performed experiments using
our UC Magma Brewery to see if we can recreate how the Tarawera lava behaved as it flowed.
``We discovered that popcorn-like rock on the edges of Tarawera was evidence that big chunks had fallen off during
eruptions, producing clouds of hot gas, ash and rocks that incinerated the land beneath the volcano. These events pose a
significant hazard at lava domes in New Zealand and around the world.
``At Mt Ngongotaha, I found the lava dome behaved quite differently to Mt Tarawera, and part of my research was to look
into why this was.’’
Dr Kennedy says Dr Ashwell arrived in New Zealand a few years ago as a fresh-faced British farm boy with no money and
little experience outside the UK.
``He did know he wanted to study for a PhD in volcanology at UC. Five years later Paul has won awards for his
ground-breaking research and is leading trips to New Zealand volcanoes and to the Antarctic.
``Paul has followed in the footsteps of one of the first volcanologists in New Zealand, Professor Jim Cole, by studying
the eruptions of Mt Tarawera. Paul’s research revealed that Mt Tarawera was not plugged by a single large lava dome
prior to the 1886 eruption as previously thought.
``Recently, Paul was a postgraduate field tutor in the Antarctic guiding students around the volcanoes that surround
Scott Base, New Zealand’s field station for scientific research in Antarctica.
``Paul’s life changing experience in Christchurch and at UC will allow him to stay in Christchurch teaching geology to
undergraduate students and to continue researching volcanoes which is great news,’’ Dr Kennedy says.
Ends