New 3D model of Mt Ruapehu to predict collapses

For the first time, scientists are creating a 3D geotechnical model of Mt Ruapehu to understand its stability.

They want to understand what's happening under the volcano's surface - and adjudge whether there's any potential for collapse.

When a dam at the rim of Mt Ruapehu collapsed in 2007, water escaped from the lake, rushed down the volcano, and created a lahar: a fast-flowing mix of rock, debris and water.

Lauren Schaefer is part of a team modelling the volcano using aerial and field surveys and computer simulation.

"Our ultimate aim is to determine how fast and how far a potential collapse or lahar could be."

She also hopes to understand how to best manage its hazards.

It's the first time such 3D modelling has been done.

The 1953 Tangiwai disaster was caused by a collapse at Ruapehu that weakened the Whangaehu river bridge.

"Mt Ruapehu has a history of collapse hazards; the geologic record tells us there have been collapses similar in size to Mt St Helen in 1980."

The eruption of Mt St Helen in Washington State triggered the largest landslide in recorded history, killing 57 people and scattering ash across more than 10 states.

Sensors on Ruapehu's surface record more than just pictures, telling the team what the material is composed of on the ground. Another looks at how magnetic the material is beneath the surface.

"Some things, like lava, are more magnetic than things like clay."

In its current state, Schaefer says, the risk of a lahar is low - but there can be many triggers.

"The potential for these areas to collapse is if an earthquake were to happen or another volcanic eruption - even material can weaken over time."

Prediction is the ultimate goal, she says, but that's very hard to do. 

Newshub.