Japan's numerous volcanoes could hold the secret to predicting future eruptions in New Zealand.
While Aotearoa has just 12 active volcanoes, Japan has 111, and that's a drawcard for Kiwi volcanologist Chris Conway who is working for the Geological Survey of Japan.
"There's a lot of eruptive activity that's occurred over the last 100 years and back into history as well, so we have great records of volcanic activity and behaviour that we can use to better understand volcanos around the world," Conway said.
Two of the most pressing questions for people living close to active volcanoes are: when will the next eruption occur and how much warning time will we have?
Conway is tackling these questions by studying lava and ash that formed during past eruptions in Japan.
"The information that we can gain from Japan is really helpful in identifying what precursory signals occur before eruptions," he said.
To get that information, he's carrying out chemical analyses of samples from volcanic deposits, which allows scientists to reconstruct the underground processes of magma formation and movement. These timelines can then be matched with the surface records of volcanic unrest and activity to build up a detailed picture of how and when eruptions are initiated.
New Zealand's had only a few well-observed eruptions, so Japan's findings are helping Kiwi scientists with their predictions.
"We study the long-term frequency of eruptions to hopefully get a better handle on when eruptions may occur in future. We now have less uncertainty, or better constraints on when volcanos will transition from unrest to a state of eruption," said Conway.
"That gives us a better understanding of time frames for hazard mitigation, or an evacuation from dangerous areas."
Japan, like New Zealand, is perched on top of the 'Ring of Fire' - a tectonic belt of volcanoes and fault lines. But the country has much more frequent volcanic activity, making it an exciting place for volcanologists to study.
His colleague, volcanologist Kiki Matsumoto, is helping him find research when future eruptions will happen, and how much warning they might get.
"So I'm looking at the texture and thinking about the physics of the materials. What I've discovered is the morphology of the materials change day-by-day," said Matsumoto.
Scientists from Japan and New Zealand have been collaborating for over 20 years on this type of hazard research, and Matsumoto said it's been a valuable experience.
"We can learn from New Zealand systems and researchers as well," she said.
Conway said learning from case studies with well-documented volcanic activity is vital for improving New Zealand's ability to mitigate eruption hazards.
Alexa Cook's trip to Japan to cover this story was funded by the Asia New Zealand Foundation.
