Stunning footage shows Papua New Guinea's Bagana volcano leaking toxic gases

Volcanologists have captured stunning footage of "one of the most active volcanoes in the world".

Kiwi expert Dr Ian Schipper has just returned from an expedition to Papua New Guinea's remote and unstable Bagana volcano, which is leaking toxic volcanic gases.

But instead of the thousands of tonnes per day of sulphur dioxide scientists anticipated, they found Bagana was emitting much less.

"From satellite observation, we expected Bagana to be one of the top ten gas emitters in the world," he says.

Dr Schipper operated advanced drones mounted with instruments used to analyse the gases, which confirmed the findings.

But he says that "there's no telling whether it will stay that way".

Dr Schipper says the expedition to Papua New Guinea was a great way to test, and refine his technology in a difficult environment.

"One of the most important lessons for me has been that each volcano presents a very unique challenge. We couldn't get so close to Bagana because of its instability, so the distance and speed the drones had to achieve was the most challenging."

His next trip will be to New Zealand's most active volcano, White Island.

"Because White Island is comparatively easier to access, we'll be aiming to get the drones as close to the crater as possible to get more concentrated samples," he says.

The Earthquake Commission's Dr Jo Horrocks, a volcanologist herself, says this will help with research to prepare for a natural disaster.

"The volcano pumps out some really toxic gases, so it would be fantastic to understand exactly what those are so we can understand more about a potential eruption at White Island," she says.