A suspected earthquake in the North East of England is likely to have been a "sonic" event such as a fast plane flying in the area, the British Geological Survey said.
People living in Northumberland and Tyneside called police after buildings shook and loud rumbling was heard.
Northumbria Police said there were no injuries or reports of any damage.
The British Geological Survey said it had received calls from people in Northumberland and Tyne and Wear, with reports including "I heard a low frequency rumble", that the "whole house shook" or the caller "heard a very loud boom".
A spokesman said: "Data from the BGS seismic networks in the region were examined and a signal consistent with a possible sonic origin was recorded at approximately 15.13.
"The reports received are also consistent with historical observations received for previous events with a sonic origin."
A Northumbria Police spokesman said: "We have had a few people from people in the Berwick area about loud noises and buildings vibrating. We are looking into these. There has not been any reports of any damage."
The sonic boom was caused by a Tornado jet breaking the sound barrier in a pre-planned sortie over the sea.
An RAF spokesman said: "The RAF can confirm that a single Tornado GR4 from RAF Lossiemouth completed a pre-planned supersonic run off the coast of Northumberland this afternoon during a sortie to RAF Marham in Norfolk.
"The supersonic element of the flight was conducted in accordance with RAF flying training rules, which state that aircraft should be more than 10 miles from the coast. Any inconvenience caused to local residents is regretted."