A mild earthquake hit Perthshire late on Thursday evening, police have confirmed.
The tremor measured 2.7 on the Richter Scale
The epicentre of the tremor was five kilometres north west of Killin, north of Stirling.
Several householders called Central Scotland Police after hearing a mystery large bang at about 2220 GMT.
Some described it as an explosion or sonic boom and others said they felt the ground shake and their windows rattled.
Once an emergency had been ruled out, police contacted the British Geological Survey.
Records were checked and it was found that there had been a tremor, registering 2.7 on the Richter Scale.
Senior seismologist Brian Bapti said that although it was a "pretty small" earthquake by global and UK standards, it would have caused public concern.
He told the BBC's Good Morning Scotland programme: "We experience about three earthquakes of magnitude and about five of about this size in the UK every year.
"The crust below us is riddled with faults and the UK is still under some tectonic stress.
"These earthquakes are the result of present day stresses combining with ancient faults in crusts.
"It's very difficult to assign an earthquake this small to a particular fault but I would probably expect last night's one to have occurred on quite a small fault."
He said there had been a sequence of tremors in the Aberfoyle area in September 2003.
An earthquake measuring 4.9 on the Richter scale hit nearby Comrie in 1839.
Mr Bapti added: "We certainly can't predict earthquakes of this size and nobody around the world has successfully predicted any although there's been a huge amount of research into earthquake prediction."