Loud booms heard across the South Cornwall coast from out to sea last night prompted much speculation on social media about their source.

Among the theories mooted about the source of the booms are blasting at Budock Vean Quarry, bow waves from passing boats rebounding in caves, sonic booms from jets or even live firing out at sea.

People were commenting saying the many loud booms could be heard all the way from Castle Beach to Coverack. They were described as being in groups of three, four and five going off 12 to 16 times.

Former Packet journalist, and now columnist Mike Truscott, said that he had checked for seismic activity after hearing the booms but nothing was registering.

"Not too surprised nothing showing on the seismo, as the booms were too consistent," he said. "Nothing random about them. They didn't even sound like the blasting noises we used to hear quite often from the quarries.

"Easier to imagine a warship firing off way out to sea. Sonic booms? Yes, very similar to what I recall of them when Concorde was overflying, except that there were so many of them (booms last night) - must have been a good 12 to 16 of them, three, four or five at a time, with short intervals in between the batches."

Siobhan Garland came up with the bow waves in caves theory. "Heard it on Swanpool beach," she said. "The sea was flat calm, my theory was bow waves created by passing boats which were then booming in caves, then all calm again, it's the only thing I could come up with, sorry!"

Sara Turk also described the sounds being like waves echoing in caves and put forward the theory that it was live fire exercises in Falmouth Bay 'danger' area.

"It seems the Navy are currently conducting live fire exercises in the Falmouth Bay ‘Danger area’. Which would account for the noises," she said. "It has been heard out at sea from everywhere this evening. People commenting from all over, Falmouth, Coverack etc. We were at Castle Beach, Falmouth and it was very eerie, everyone wondering what it was!

"I can only liken the noise to huge waves crashing into large caves and making a very loud echoing booming sound. But it was heard over a large area, over a longish period of time!

"We saw the Lynx helicopter doing a low fly past and it wasn’t that. Maybe it was something to do with it though. Were the navy on exercise last night?

However, a spokesman for RNAS Culdrose said that the booms were nothing to do with RNAS Culdrose with their last aircraft was back down on the ground by just before 5pm yesterday.

Ray Skin Longstaff said: "I was playing golf at Falmouth we heard it a few times it was very strange."

Samantha Richards pointed out that there was Notice to Airman out yesterday. A notice to airmen (NOTAM) is a notice filed with an aviation authority to alert aircraft pilots of potential hazards along a flight route or at a location.

"Possible military exercises, there's a NOTAM out yesterday for low flying military jets in the Falmouth area.

The MoD have been contacted to see if they can shed any further light on the matter.

Do you know what the booms were? Let us know your theories on the comments section or on our Facebook