The UK gets hundreds of Earthquakes each year, but they are so small they are hardly ever felt.
But every decade or so we experience a much more powerful earthquake that is felt on the surface, causing shaking and a deep rumbling noise.
The British Geological Survey confirmed that the epicentre of the earthquake that was felt on Saturday was in Swansea in Wales, measuring 4.4 on the Richter scale and struck around 2:31pm.
SEISMIC ALERT: CWMLLYNFELL, SOUTH WALES 17 FEBRARY 2018 14:31 UTC 4.4 ML
LAT/LONG : 51.776° North / 3.837° West
GRID REF : 273.3 kmE / 210.2 kmN
DEPTH : 7.4 km
MAGNITUDE : 4.4 ML
— BGS (@BritGeoSurvey) February 17, 2018
Buildings to shook right across Merseyside, with many people reporting their experiences on social media.
It has also been confirmed that it was the biggest onshore earthquake in the UK in a decade.
A Brit Geo spokesperson said it was “reasonably-sized” and that the effects had been felt as far afield as Devon and Birmingham.
“This is the largest earthquake in mainland UK since the 5.2 magnitude Market Rasen earthquake in 2008.”
— BBC News (UK) (@BBCNews) February 17, 2018
Why was it felt so widely ?
The earthquake struck 7km underground the welsh rock of Swansea, so it is here where there was movement in a rock fault.
When rocks slide past each other under intense forces, the rock can suddenly slip creating huge amounts of energy that is sent out in shockwaves causing an earthquake.
The more energy involved the bigger the shaking, simply this quake used around 40 times more energy than the smaller quakes the UK experiences, hence why it was felt right across the country.
The largest known British earthquake occurred near the Dogger Bank in 1931, with a magnitude of 6.1.
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