An earthquake with a magnitude of at least 4.3 has shaken southern England.
The quake struck at 8.18am, with the British Geological Survey placing the epicentre 7.5 miles off the Dover coast.
The US Geological Survey had put the magnitude at 4.7, while the European monitoring station had measured 5.0.
Kent Fire and Rescue Service received 200 emergency calls and was dealing with "several incidents".
Most involved reports of structural damage to buildings.
Chimneys have fallen down while local energy supplier EDF Energy said that thousands of its customers had lost power.
However, supplies have now been restored in the Folkestone and Dover areas.
One woman in her 30s was taken to hospital with minor head and neck injuries.
More than 100 people who fled their homes were comforted by the Salvation Army with shelter and refreshments at a church in Folkestone.
Salvation Army minister Captain Peter West said: "Personnel were on the scene providing refreshments and emotional support. A lot of people were upset and confused, but there was no serious trauma."
It is understood householders felt the tremor as far afield as East Sussex, Essex and Suffolk.
Eurostar said the quake had not affected services across the Channel.
Kent police have advised people to stay indoors unless they have structural damage to their homes.
Anyone who smells gas is urged to contact authorities.
Residents said when they heard the initial bang they feared an explosion at the Dungeness nuclear power facility.
There have been reports of mild aftershocks since the quake.
Peter Gilroy, chief executive of Kent County Council, told Sky News: "I'm very satisfied that the emergency service response was absolutely first rate.
"Lots of people are frightened and they feel it's very chaotic in the early stages of the incident."
Mr Gilroy said building engineers from across the county will be "systematically checking" properties in affected areas for structural damage.
He said this process will take weeks rather than days.