Leighton Buzzard has been hit by an earthquake for the third time in two weeks.
The magnitude three tremor hit the Bedfordshire town at 8.32 on Tuesday morning, the British Geological Survey confirmed.
It was a second aftershock following the initial event on September 8, which was a magnitude 3.5 event.
Glenn Ford, a seismologist with the BGS, told the PA news agency: “What we’re seeing here is a small aftershock from that earthquake.”
The first aftershock, which was measured by the BGS at magnitude 2.1, hit on September 14.
While earthquakes have not occurred frequently in the area in the past, Mr Ford said the activity was “typical behaviour” which had been seen in different areas of the UK “on many occasions”.
He added: “There’s obviously been some stress been building up in that particular area and we’ve had the initial earthquake.
“It’s maybe just still rebalancing the stress regime in that particular part of the world and we’re getting these little aftershocks occurring as well.”
Sheila O’Connell, an NHS worker who lives in Leighton Buzzard, said Tuesday’s quake felt similar to the event two weeks ago.
“It was a bang and it was a shake, a real shake,” she told PA. “I felt the building shake.
“It was almost the same as the first one.
“My instinct was, ‘Is that another earthquake? What is going on in Leighton Buzzard?’”
She said she did not feel unsafe, but added: “If they carry on it might well come to that.”
Jo Reggelt, who lives in nearby Bletchley, said it was similar to the September 8 quake “but on a lesser scale”.
“The conservatory rattled again, there was that sort of muffled sound of a gas explosion,” he told PA.
Earthquake expert Dr Matthew Blackett, a reader in natural hazards at Coventry University, describes what may have caused the tremors and why the Bedfordshire community has become a place of environmental interest.
– What happened?
The people of Leighton Buzzard awoke to – or were awoken by – a familiar feeling.
The latest tremor, with a magnitude of 3.0, hit the Bedfordshire town on Tuesday morning.
It followed the initial event on September 8 and a first aftershock on September 13, which were magnitude 3.5 and 2.1, respectively.
All three were deemed fairly low on the scale.
An earthquake is the fracturing of solid rock.
In Bedfordshire, the quake started some several hundred metres below the surface, in hidden fault lines, Dr Blackett said.
– Why Leighton Buzzard?
“It’s very, very odd,” said Dr Blackett.
The British Isles has moved north from its position near the equator over the last 300-400 million years, with periods of tectonic plate compression and suppression.
But, today, the country is in a stable position in the middle of a tectonic plate. It means earthquakes are unlikely.
“What seems to have happened is that this was an initial earthquake in a hidden fault, some stress or other has caused it,” Dr Blackett said.
“These two subsequent events are a readjustment of the fault lines to come back to some sort of stability.
“The crust has to adjust itself to become stable again, that seems to have happened to the poor people of Leighton Buzzard.”
He said there was nothing to suggest in advance that Leighton Buzzard would be hit by the tremors.
– So Leighton Buzzard was unlucky then?
Looks like it, yes.
What seems certain now, though, is that experts will be keen to explore the possibility of further hidden fault lines deep into the Earth’s crust.
– Should people in the area be worried about further tremors?
No, Dr Blackett said.
“It is quite possible that that sequence is now done, but it might be that there are still stresses there,” he said.
“If there are (further tremors), I think it will only be minor events.”
– Finally, the new HS2 rail link will be built nearby – is there any chance the tremors were caused by drilling or preparation works?
Absolutely not, Dr Blackett said.
For a start, the only significant work has been in and around west London.
Even then, any work will not cause problems.