Second earthquake in 24 hours hits UK: Experts warn of a hidden fault line - and say there could be bigger tremors in the future
- A magnitude 3.5 earthquake has struck Rutland again in the East Midlands
- The tremors were felt at 7:50am today, just 24 hours after the last one
- Region has now been hit by two earthquakes in quick succession
- These types of earthquake are themselves small and common in the world
- But seismologists warn there could be hidden fault lines under the UK
- These could lead to larger earthquakes occurring on the mainland in future
An earthquake has struck the Rutland area of the East Midlands again, just 24 hours after a similar tremor shook houses in the area for ten seconds.
Initial data released by the British Geological Survey (BGS) said the latest 3.5-magnitude quake, the biggest in the region since October 2001, struck the Oakham area at around 7:50 am today.
Yesterday’s 3.2-magnitude quake occurred at 7:07am and reportedly shook houses.
The UK is not itself generally associated with earthquakes. However, according to the BGS, 20 to 30 tremors are felt every year, while a few smaller ones are tracked by sensitive instruments.
While most are small and cause no damage, there is the potential for larger ones in future.
The UK does not lie on a major fault line, but it’s thought that smaller unseen fault lines, known as blind fault lines, are deeper underground.
Nearby tectonic boundaries such as that between Eurasia and Africa can induce tremors in smaller fault lines like the ones in the UK.
‘If you look at your hand, imagine the main lines as a major tectonic boundary,’ Glenn Ford, a seismologist at the BGS, explains to MailOnline.
‘Between these are little lines, and if you gently squeeze your hand you see that even these smaller lines move back and forwards.’
While today’s earthquake was large for the UK, tremors are a common and largely unnoticed occurrence across the rest of the world.
It is estimated that 17,000 to 20,000 earthquakes of this size occur every year in the world.
However, seismologists think that a larger one could strike the mainland UK one day and cause significant damage.
‘This particular one was 3.5 which in UK terms is quite significant,’ says Ford.
‘We maybe get one or two a year of that size.
‘We had a 4.1 in the Bristol Channel back on the 20th of February. They’re not like buses - they come when they want, but statistically we don’t get many of this size.’
For residents of Rutland, the tremors proved to be cause for some alarm.
Within half an hour of the first quake striking, the BGS had received around 140 calls from people who had felt the tremors.
According to the BGS, an earthquake has to reach a magnitude of 4.5 before it can be expected to do any damage. Emergency services have not reported any casualties or damage to property.
Among those who felt yesterday’s tremor was former English rugby union player Austin Healey.
He tweeted: ‘We’ve just had an earthquake in Oakham. The house was shaking for about 10 secs.’
Louise Warren, 40, was getting four year-old son Adam ready for school when it struck.
Ms Warrwen, of Stamford, Lincolnshire, said: ‘The shaking sound started quite suddenly and my electric toothbrush fell from the shelf into my sink.
'It felt like a lorry going past my house but about ten times louder. There was a second shake soon after the first one stopped.
'I wasn't too scared because I remember when we had a tremor here about eight years ago.
'My son was a bit frightened because he'd never felt anything like it before. But he's a boy, so he did think it was pretty cool.'
The reason for two earthquakes occurring so close to each other might be the result of stresses building up in the faults.
‘In other parts of the world they wouldn’t be talking about this,’ says Ford.
‘The tremor is very, very small compared to the quakes we see in areas of high seismic activity such as Greece.
‘For us 90 per cent of earthquakes are unnoticed, but when [the bigger ones] do happen we get alarmed.
‘The public is not calibrated to them, maybe because people think they don’t actually happen.’
Ford says this one was probably more noticeable as well because many people are off work for the Easter holiday.
‘This one happened at a good time today for people to feel it.
‘They are lying down in an ideal position to feel earthquakes, very small tremors that people would never expect to feel.
‘If you look at what people describe it’s like a large lorry going past.
‘An earthquake of this size can go unnoticed up in the highlands, or if it happens at a time of day where people are busy or in road traffic.
‘Many people today also realise another happened yesterday, so they are more aware.
‘People are looking out for them now, and in shops and supermarkets they’ll be saying “oh, did you feel the earthquake?” to each other.’
The biggest earthquake on record to hit the UK was a 6.1 back in 1931.
Fortunately this one hit offshore and didn’t cause much damage on the mainland, but Ford says there is the possibility that one of this size could still hit the mainland UK.
‘We’re quite a distance from immediate fault lines, like the Mid-Atlantic Ridge running up to Iceland.
‘But we do have a major plate tectonic boundary between the Eurasian plate and the African plate.
‘The African plate is rubbing up on the Eurasian plate, so that causes stresses that build up on existing fault lines the UK has.
‘Some could be a few metres long, some are long, but over time stresses build up.
‘Perhaps historically many millions of years ago they could have been more active.
‘I’m sure there were larger earthquakes at some time.’
When these might occur though, or why these two were localised in Rutland, remains a mystery.
‘There is a possibility one of that size can hit the mainland UK,’ Ford continues.
‘The unusual feature of earthquakes is we don’t know where they might occur.’
‘We don’t know why it was localised in Rutland.
‘There could be faults underground that we don’t know of.
‘In other parts of the world with earthquakes they don’t know of all the fault lines.
‘There could be lots of blind fault lines, we’ve got a long way to go to understand these processes through seismology.’