Sonic boom theory for 'explosion'

A US FA18 Hornet was photographed breaking the sound barrier in 1999

A loud explosion which sent residents running for cover has been heard in Wales for the second time in less than a week.

Windows and homes shook in areas of Denbighshire and Conwy at around 17.50BST on Tuesday.

North Wales Police received calls from worried residents who thought there had been an earthquake.

Last week people living in Llandrindod Wells in Powys reported a similar incident.

An official from the British Geological Survey in Edinburgh said the signal they had picked up from both reports was consistent with being of sonic origin rather than an earthquake - possibly from an aircraft over the sea.

I ran out of the house with my husband and we thought the explosion store in the quarry had blown Sue Coleman

The loud bang was heard from Rhyl in the east to Conwy in the west, and several miles inland from Abergele.

Chris Roberts from Prestatyn said she had been out walking her dog when she heard the explosion.

"My poor dog nearly jumped out of his skin," she said.

"I was walking the dog at about 10 to six and I heard this almighty boom.

"It was loud and I wondered if there'd been an accident."

Sue Coleman lives a few miles away near Llysfaen quarry in Colwyn Bay, she said the noise was so loud she thought the quarry had exploded.

"Everyday we have explosions at the quarry but this was the biggest explosion I have ever heard," she said.

Sonic boom

"I ran out of the house with my husband and we thought the explosion store in the quarry had blown.

"The house shook worse than I've ever known," she added.

Glenn Ford, a seismologist with the British Geological Survey in Edinburgh, said they had had no signals "consistent with an earthquake in the area".

"The small earthquakes are very similar to effects observed by sonic booms," he said.

"It could have been caused by an aircraft, they can do fast turns and the wing can go supersonic," he added.

However, Lois Demack said she regularly attends air shows and the noise did not sound like a sonic boom to her.

"I was visiting a doctor's in Meliden and there was a big bang...I was expecting the mountain to come down behind us," she said.

"I go to air shows so I didn't think it was a sonic boom," she added.