The violent eruption of Hunga-Tonga-Hunga-Ha’apai generated a tsunami and blanketed the islands of the Kingdom of Tonga in volcanic ash. Video / Supplied
Scientists say undersea volcanic eruptions pose a real but poorly understood threat to the undersea internet cables that link New Zealand to the world.
A multimillion-dollar study aims to pinpoint the 10 most dangerous submarine volcanoes that threaten our shores and internet infrastructure.
It follows 2022′s spectacular Hunga Tonga-Hunga Ha’apai eruption, which knocked out internet across large parts of Tonga.
Scientists are investigating what they call a “critical hazard blind spot” for New Zealand: the risk of faraway Pacific eruptions to undersea cables we rely upon for internet access.
Since then, undersea landslides resulting from the eruption’s impacts have caused more damage to submarine cables.
These networks, stretching from New Zealand to Australia and the US, also keep Kiwis linked to the world – and there is considered to be enough of them, with enough excess capacity, that one single outage wouldn’t completely knock out our internet.
Still, University of Auckland volcanologist Professor Shane Cronin said we don’t know enough about the risk posed by the 80 or so undersea volcanoes in our wider region.
Submarine cables, stretching from New Zealand to Australia and the US, keep Kiwis linked to the world – and there’s considered enough of them, with enough excess capacity, that one single outage wouldn’t completely knock out our internet. Image / TCF
“The reason why submarine volcanoes are overlooked is that we don’t easily see them,” he said.
“Many of these near New Zealand are potentially capable of generating tsunami waves with widely destructive mass flows – and our challenge is to figure out which ones are the most dangerous.”
In a new multimillion-dollar project, Cronin and his team will investigate a range of factors that make a given volcano a big threat – including how large, steep or shallow it is, its history, and whether our cables and shores lie in the path of its eruption flows.
“We have already some clues of this from past studies and from international experience – but we need to filter through the long list of volcanoes and target attention to those that are most significant for us.”
Cronin said the cost of mapping all those volcanoes was “huge”, and presently, scientists could only draw on a handful of small patches of the sea floor that had been explored in detail.
To overcome that problem, the researchers planned to use data gathered by Nasa satellites, along with information collected on research voyages.
After pinpointing the 10 undersea volcanoes that posed the biggest danger to New Zealand, the team will use cutting-edge new modelling approaches to simulate their impacts.
Cronin said the project could ultimately improve our data security.
University of Auckland volcanologist Professor Shane Cronin. Photo / Tonga Geological Services.
It could also tell scientists much more about complex geophysical signals that could alert monitoring stations to a tsunami caused by a big underwater blow.
“Remember, the tsunami from the Hunga Tonga-Hunga Ha’apai eruption arrived in New Zealand, Fiji and Vanuatu with virtually no warning, because models used by the International Tsunami Warning Centre are tuned to earthquake sources, not volcanic ones,” Cronin said.
“We plan to create new templates for adding volcanic warning to these systems.”
The study runs alongside a separate University of Auckland project, also supported through the Ministry of Business, Innovation and Employment’s Endeavour Fund, investigating whether a “hyper-explosive” submarine eruption like Hunga could happen in New Zealand.
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.
