Reports of ”earthquake-like” tremors in north-east Scotland may have been supersonic jets on an emergency scramble.
Coastal residents from Aberdeen to Fife contacted police after hearing a dull roar and feeling the ground shake on Tuesday night.
Staff at the British Geological Survey were quick to rule out any seismic activity and the Ministry of Defence confirmed it was likely that a sonic boom triggered the rumbling.
Former naval officer and aviation expert Jim Ferguson said the ”bang” could have come from fighter planes at RAF Leuchars on an unexpected Quick Reaction Alert (QRA).
Similar rumbling was heard in the south of England last month, as two Eurofighter Typhoon jets responded to an emergency hi-jack distress code mistakenly issued by a helicopter pilot.
Mr Ferguson said: ”They have to get permission for the sonic bang and it is quite possible it could have been a QRA call, which means they have to get out somewhere quickly.
”It could have been a training mission but they don’t use them (sonic booms) as often as they used to these days.”
RAF Wing Commander Martin Tinworth said Typhoon jets from Leuchars regularly operate in the area between 10 and 35 miles off the coastline but claimed it is rare for them to be heard.
”Although we can’t confirm what it was, it is possible that is was sonic boom from an aircraft,” he said. ”We do these flights all the time and, generally, the aircraft will fly supersonic over the sea at various times throughout the day and night, at a set distance away from the coast.
”At the moment, there is an anti-cyclone above the UK creating an area of very high pressure which allows sound to travel further than it would normally do.”
RAF Lossiemouth ruled out its fighter jets, saying the planes were too far away for the effects to be felt down the east coast.
A spokesman for the British Geological Survey confirmed it was not an earthquake that sparked the public concern, but added that a sonic boom could feel like a seismic shift. He said the most likely explanation for the tremors was a supersonic aircraft but claimed the noise could also have been caused by a clap of thunder being carried by high pressure.
A sonic boom occurs when shockwaves from an object travel through the air faster than the speed of sound. The noise can often be heard from up to 100 miles away and one Wormit resident said he experienced a tremor at 7.30pm.
He added: ”I heard a noise and felt it in the ground, too. I wondered if it was connected to Leuchars.”
Inverbervie shop worker Theresa Rae said customers had reported bangs and shaking, while Twitter and Facebook had hundreds of posts from people discussing the ”earthquake”.
Grampian Police confirmed that reports from members of the public had been received.
A force spokesman said: ”The calls related to the period between 8.45pm and 11.15pm from areas around and along the coastline south of Aberdeen, including Torry, Portlethen, Stonehaven, St Cyrus, Inverbervie and Gourdon. There were no reports of any injuries or damage as a result of the incident.”