An earthquake with a magnitude of 3.9 has struck in the English Channel, the British Geological Survey (BGS) said.
The quake had a depth of 10km and its epicentre was south of Portsmouth, according to the BGS.
Residents in parts of West Sussex reported buildings shaking for a few seconds at about 0800 BST.
Sussex Police, Solent Coastguard and West Sussex Fire and Rescue Service said they had not been called out to any incidents related to it.
'Largest since 1734'
David Kerridge, from the BGS, said it was the biggest incident of its kind in the area for nearly 300 years.
He said: "This is the largest earthquake in this area since a magnitude 4.5 event in 1734.
"Historically, there have been two other significant events nearby - a magnitude 5.0 earthquake in 1878 and a magnitude 4.3 earthquake in 1750.
"In the UK, we experience an earthquake of this magnitude approximately every two years."
Small earthquakes are not uncommon in the British Isles.
In January a 3.6-magnitude quake struck 9km (5.5 miles) north-west of Ripon, North Yorkshire.