Australian scientists are part of a team that has accidentally made a breakthrough that could lead to an improved early warning system for volcanic eruptions.

Monash University researchers, along with those from universities in Newcastle, New South Wales, and Liverpool in the UK, were looking at the natural plumbing systems within volcanoes when they discovered a trigger-point for volcanic eruptions.

Professor Sandy Cruden from Monash University's School of Earth, Atmosphere and Environment said they found that after a pressure drop occurred within the volcano's internal pipes, an eruption can follow.

This pressure drop can potentially be used by volcanologists to predict a catastrophic eruption, Professor Cruden said.

"The importance is quite significant particularly if you are part of a community that lives next door to a volcano," he said.

"The whole idea is to engineer early warning systems so people can be told with a huge degree of confidence when to get out of the way."

Lead author Dr Janine Kavanagh from the University of Liverpool said with more than 600 million people worldwide living near a volcano at risk of eruptive activity, it is more important than ever that triggering mechanisms are improved.

This previously unrecognised trigger could also alleviate the "headache" volcanic eruptions cause civil aviation by providing early and accurate warnings to authorities when they should divert aircraft.

"There is also a strong economic incentive to understand the causes of volcanic activity as demonstrated in 2010 by the eruption of Eyjafjallajökull, Iceland, which caused air-traffic disruption across Europe for more than one month, with an estimated $2.3 billion loss in

revenue to the airline industry," Dr Kavanagh said.

Scientists used jelly and lasers in experiment

In the experiments, the scientists used a tank filled with jelly into which coloured water was injected to stimulate the moving magma.

A high-speed camera and synchronised laser were used to observe what happened inside the tank as the magma moved upwards.

The scientists then discovered a significant pressure drop occurred when a vertically moving sheet of magma called a dyke turned into a horizontally moving sheet called a sill.

A pressure drop causes the magma to release dissolved gasses as bubbles and those bubbles cause the magma to expand, and if that happens fast enough, an eruption can occur, Professor Cruden said.

"It's similar to removing a cap from a bottle of shaken fizzy drink — the pressure drop causes bubbles to form and the associated increase in volume results in a fountain of foam erupting from the bottle," he said.

Professor Cruden said the scientists were simply trying to understand the basic physics of how magma moves around the earth when they uncovered this pressure drop.

"[It] was completely unexpected and a very interesting result," she said.

"We hope volcanologists will eventually incorporate this new finding into their toolbox."