GNS Science natural hazard and risk scientist Dr Josh Hayes said ashfall from a future eruption could affect thousands of buildings around the North Island.
According to GNS estimates, light ashfall erupted from volcanoes like Ruapehu and Ngāuruhoe was likely to be less than 50mm thick.
But that was still enough to cause minor damage to houses, contaminate water supplies, block sewers, cut electricity networks and affect livestock.
Most pastures would be killed by ash more than 50mm thick, while weaker roof structures could collapse and trees stripped of foliage under ash more than 100mm thick.
“Fortunately, around some of our volcanoes such as Ruapehu, Tongariro, and Taranaki, we have national parks, which limits building up large developments in high-risk locations,” Hayes said.
That meant it’d take large “and relatively rare” eruptions to cause heavy damage from ash.
“For example, the 1995-96 eruptions of Ruapehu produced fairly modest amounts of building damage, mainly associated with damage to gutters and ash clean-up,” he said.
“However, we know looking at the geological record that these volcanoes have previously produced larger eruptions that if they were to occur today could cause more substantial damage.”
Ahead of the next major eruption, Hayes and a team of scientists are building a sophisticated forecasting model that’d allow agencies to quickly gauge ashfall impact, saving time and resources.
The new research project, Natural Hazards Commission, aimed to fill a gap between internationally developed models used overseas and data that’d be collected immediately after a local eruption.
“Knowing where the ash will travel and forecasting the amount of ashfall loading that accumulates on roofs in different areas will be the key metric when we assess the damage to buildings from volcanic ash.”
It’d also mean emergency efforts could be directed at the right places as the situation unfolded.
The new model will use scientific data, engineering reports and satellite images, but also crowd-sourced data, like social media, to build a comprehensive picture after an eruption.
“Naturally the reliability of information varies across different sources, so our methodology will factor in the reliability of different post-event data.”
The team, from GNS, the University of Canterbury and Singapore’s Nanyang Technological University, expect to complete the model by the end of next year.
“We hope to eventually be able to expand the approach to all other natural hazards.”
Jamie Morton is a specialist in science and environmental reporting. He joined the Herald in 2011 and writes about everything from conservation and climate change to natural hazards and new technology.
Sign up to The Daily H, a free newsletter curated by our editors and delivered straight to your inbox every weekday.
This post was originally published on here
