Police say there have been no injuries or damage to buildings after a magnitude 4.2 earthquake was felt in parts of Kent.
Seismologists at the British Geological Survey (BGS) confirmed the tremor, which was felt in areas including Ramsgate.
The organisation tweeted: “Prelim data now online ... 4.2 magnitude earthquake nr Sandwich, Kent.”
Kent Police was inundated with calls about the incident.
A spokesman said: “It has now been confirmed parts of East Kent has been affected by an earthquake measuring just 4.3 on the Richter scale (British Geological Survey).
Kent Police began receiving reports of the earthquake tremor in the East Kent area at around 2.57am today. Police and Kent Fire and Rescue Services have not received any reports of structural damage or injuries.
“We will continue to liaise with our partner agencies to ensure we are providing help and support in any areas needed,” the police spokesman said.
Residents tweeted their reactions after being awoken by the tremors.
Vikki Petts said: “So we just had a 4.3 magnitude earthquake in Kent and my housemates slept through the entire thing. certainly woke me up!”
Jonathan Tapp said: “Earthquake in East Kent and now can’t get back to sleep. Despite months spent in NZ this is my first one that I’ve felt.”
Iain Buchanan, of Ramsgate, said: “So I’m not going mental, my house shook due to an earthquake in Kent of all places. Thank god for 24 hrs news & social media to find out.”
He added: “Lying in bed when the house suddenly shook. Thought something had collapsed outside, so got up to check.
“I’ve looked outside and all appears to be fine in the street. No damage that I can see. Will obviously see more later when it’s lighter. Weird experience anyway.
“I actually thought it was an explosion of some sort and not an earthquake.”
Other agencies initially recorded varying measurements, including the European-Mediterranean Seismological Centre, based in Paris, said the earthquake measured 4.3 on the Richter scale.
It tweeted: “M4.3 earthquake strikes 46km SE of Southend-on-Sea (United Kingdom).”
The US Geological Survey measured the quake as magnitude 4.0.
The British Geological Survey said earthquakes similar in size to the one that struck Kent happen around every two years in the UK and about 4,500 times a year across the world.
It tweeted: “Today’s 4.2 magnitude Ramsgate earthquake is approx 260,000 times smaller than the 7.8 NepalQuake event.
“This morning’s earthquake is approx 25km north-east of the 28 April 2007 Folkestone earthquake which had a magnitude of 4.3 ML.”
The BGS said that this morning’s earthquake’s epicentre was approximately 7km south of Ramsgate.
Over 400 “felt reports” were received, including from places as far afield as Norwich, North Walsham and Cromer in Norfolk.
People reported being woken from their sleep, with windows rattling and furniture shaking.
Twitter users however made light of the quake, jokingly posting “devastating scenes” of overturned wheelie bins and garden furniture with messages such as “We will rebuild”.
Experts said it was difficult to link the earthquake to a specific fault line.
David Galloway, a seismologist with the BGS, said: “The whole of the UK is criss-crossed by thousands of fault lines but most of them are at depth.
“This means we do not pinpoint a specific earthquake to a specific fault because even if a location is a few hundred metres off it could have been a completely different fault.
“Fortunately we do not live on the plate edges - for example the San Andreas fault in California can actually be seen at the surface, but the faults in the UK are blind and most earthquakes happen at a depth of between 5km and 25km.
“Earthquakes happen all over the UK - we get some 200 a year on average. One of the scale of this morning’s only happen every two or three years.”