RAAF sonic boom "possible" cause of earthquake false alarm

On Tuesday, March 27 radio stations tweeted that a mini earth quake had occurred in the Port.

But the Examiner's calls to the federal government's Geosciene Australia confirmed while there was no seismic activity, calls had been logged between 9am and 10.30am from concerned residents who had 'felt' movement.

The geosciene spokesperson said it could be the result of a number of things including a sonic boom or weather conditions such as storms or thunder.

When asked if any RAAF Base Williamtown aircraft performed a sonic boom between Monday March 26 to Wednesday March 28, a defence spokesperson said it could not confirm "without a specific time or date".

Further requests to the defence department about an occurrence between 9am and 10.30am on Tuesday, March 27 confirmed it was possible.

"Air Force can confirm that the aircraft were undertaking supersonic flight during this time and a sonic boom was possible given the weather conditions at this time," the spokesperson said

"Sonic booms can travel some distances and their propagation can be enhanced by certain weather conditions such as high humidity and cloud cover."

The spokeksperson said F/A-18 Hornet aircraft, were undertaking routine training in the over water airspace to the east of Port Stephens early last week.

The spokesperson went on to say that air force pilots and crews needed to experience a range of environments including flying at supersonic speeds and sonic booms could be made.

"Air force attempts to reduce noise experienced by residents living near bases, so any flying faster than mach 1, approximately 1,225km/h, is conducted over the ocean, well off the coast to avoid the possibility of a sonic boom occurring near populated areas," the spokesperson said.

Previously in December 2009, Williamtown RAAF base spokesperson suggested that supersonic activity by aircraft was responsible for shaking felt by Hunter residents.