MANY Lower River residents felt the ground move under their feet on Thursday night in what was believed to be a sonic boom.
Brendan James, of Maclean, described the unusual occurrence as a ‘rumble’ that sounded as if a B-double truck was driving over their roof.
“We felt a rumble on the ground and then the windows started shaking,” he said.
“My wife and I looked at each other at the time because we thought it was someone banging on the window at first.”
Mr James said the shudder and slight rumble only lasted for five seconds.
A Royal Australian Air Force spokesman said the possible source of the tremble around 10pm was supersonic activity as part of the ECADEX major aircraft defence exercise that was a vital training exercise for air force personnel to maintain operational capacity and to practice key defence skills.
“The aircraft were operating in accordance with flight rules and restrictions for supersonic flight but at times atmospheric conditions can propagate the sound waves further than expected,” she said. “There have been recorded events of sound waves being heard from over 100 kilometres away.”
Dr Con Doolan, from the school of Mechanical Engineering at the University of Adelaide, said a sonic boom was a sound that could be heard on the ground from an aircraft travelling faster than the speed of sound.
“The shock waves cause a very distinct boom sound,” he said.Sonic boom
- A sound that can be heard on the ground from an aircraft travelling faster than the speed of sound.
- Shock waves are created and when sound reaches the ground an intense sound wave can be heard.