AUSTRALIAN researchers have released data about an unusual underwater sound recorded around the time Malaysia Airlines Flight 370 vanished.

However, the lead scientist put the chances of it being linked to the missing Boeing 777 at less than 20 per cent.

The low-frequency sound was picked up by under­water listening devices in the Indian Ocean off the west coast of Australia on March 8 this year, the same day the plane disappeared on a flight from Malaysia to Beijing with a total of 239 people on board.

Researchers at Curtin University, Western Australia, have analysed the signal to see if it may be the sound of the plane crashing into the ocean.They admit the noise could have come from a small earthquake.