Rutland hit by third earthquake in two weeks
A third earthquake in two weeks has shaken parts of Rutland in the East Midlands.
Residents around Oakham reported feeling the 1.7 magnitude quake at about 23:05 BST on Monday
The widely-known Richter scale has been generally replaced by moment magnitude scale (Mw). Richter measured the amount of movement while Mw is based on the force involved.
Mw 1.0 - 30 lb of TNT, eg construction site blast
Mw 2.0 - 1 ton of TNT eg large quarry or mine blast
Mw 3.0 - 29 tonnes of TNT
Mw 4.0 - 1 kiloton of TNT eg small atomic bomb
Mw 5.0 - 32 kiloton of TNT eg Nagasaki atomic bomb
Mw scale goes to 9
Source: British Geological Survey
On 17 and 18 April, two quakes struck the same area - the second of which was the strongest felt in the area for more than 10 years at magnitude 3.5.
The British Geological Survey said it was not unusual to have a third and said it was probably an aftershock.
The BGS recorded the epicentre as about 2km below the village of Ashwell, north of Oakham and it was felt in Oakham, Cottesmore, Ashwell, Langham and Braunston-in-Rutland.
Residents took to social networking site Twitter with the hashtag #rutlandearthquake to discuss the event, which was much weaker than the previous two.
Jack Thorpe tweeted: "So, what I thought was my neighbour putting his bin out was a THIRD #rutlandearthquake What on earth has been awakened beneath us?"
And Oakham Police also tweeted saying there was a loud bang and windows shook.
David Galloway, a seismologist at the BGS, said it was not unusual.
"What is unusual is that the second one was larger than the first," he said.
"This latest one is probably an aftershock. There could be more but it may now have released all the pressure. It is impossible to predict."
Mr Galloway said that about 400 people contacted the BGS about the first quake, on 17 April, and 1,000 got in touch regarding the second, which was three times stronger.
By contrast, only about 50 people filled in a survey about Monday's tremor.
No damage or injuries have been reported.