New Zealand has set an unwanted world record for the largest number of landslides from one event as new research reveals Cyclone Gabrielle caused about 850,000 landslides nationwide.
The data will be used by scientists to help predict the damage and danger of future natural disasters by informing councils on what land is unsuitable for houses.
When Cyclone Gabrielle gouged out chunks of earth, leaving thousands of tears streaked across the landscape, it loosened dirt and debris which then ruined hundreds of homes and created a world record that no one wanted.
University of Canterbury Lead Researcher, Tom Robinson, says months of aerial imagery and analysis has revealed just how many landslides the cyclone created.
"Our mapping suggests we could have over 800,000 landslides, which would make this a global world record for landslides triggered by a single event, a storm," he told Newshub.
The project is being led by GNS scientist Chris Massey, who is part of a large team that have been mapping over 140,000 landslides from the cyclone and creating this landslide distribution map.
"We believe it's the largest map landslide distribution that can be attributed to a single event," Massey said.
Scientists used planes, helicopters and satellites to collect high resolution images.
"It's a really complicated process. It started with Land Information New Zealand (LINZ) capturing the data in regards to optical imagery that we used to map the hillsides," he said.
"Then it also included establishing a methodology, and an army of students, checkers and quality assurance people - then we've got the expertise to get data out to end users."
One of the landslide maps created by researchers shows just how badly affected the Esk Valley was, where in some places there are more than 150 slips in one square kilometre.
"That's an extremely high density of landslides - not something we've seen since at least Cyclone Bola in the '80s," Robinson exclaimed.
It's provided valuable scientific insights, particularly for students like Julia Harvey who is doing her Masters in Disaster Risk and Resilience at the University of Canterbury.
"It's really rare for us to be involved in an event of this scale so early on in our research careers. For that reason it's really exciting to think about the wealth of knowledge that's going to come through from this event," Harvey explained.
What they have learnt from these landslides will be put into forecast models to predict how the land will behave in future weather events.
Those models will help authorities know what size some slips will be, and where to send first responders to in a natural disaster.
Massey told Newshub the information will feed into council planning and land use decisions, which could change where and how people build homes in future.
"That's our hope, that's exactly why we're doing this work," he said.
