Seismologists at the British Geological Survey are looking into reports of tremors felt in areas including Margate, a spokesman said.
The European-Mediterranean Seismological Centre, based in Paris, said the earthquake measured 4.3 on the Richter scale and struck shortly before 3am.
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.
Kent Police was inundated with calls about the incident.
The force tweeted: “We are aware of reports of tremors being felt by residents in East Kent & are monitoring the situation. No injuries have been reported.”
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 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.”