Scientists have discovered volcanoes from millions of years ago under the sea south of Australia.

Researchers used 3D seismic reflection - a geo-mapping technique that uses seismic waves to measure subsurface structures.

The teams, from the University of Adelaide in Australia, the University of Aberdeen and the Commonwealth Scientific and Industrial Research Organisation identified 26 volcanoes buried about 820ft beneath the seabed sediment.

Some of the volcanoes are up to 2,000ft in height and are surrounded by several lava features.

Nick Schofield, a senior lecturer at the University of Aberdeen's School of Geosciences, said: "The technology we have used is similar in many ways to what is used to produce ultrasound images of babies, but for the Earth.


"By using this technique we have a unique insight into a landscape that has remained hidden for millions of years."

Researchers dated the volcanoes to the Eocene epoch which happened about 50 million to 33 million years ago.

Mr Schofield added: "By using data acquired as part of oil-exploration efforts, we have been able to map these ancient lava flows in unprecedented detail."

Using the seismic data, researchers discovered that some of the ancient lava flows measure more than 21 miles long and nine miles wide.

The network of lava flows surrounding the volcanoes was likely to have been created during an undersea eruption about 35 million years ago, the study said.

Over the miles of terrain the lava flows branch into pathways, rise into plateaus and plunge into trenches to create islands of hardened lava.