An earthquake measuring 2.7 magnitude hit Cornwall just before 1am on Sunday.
Seismologists say it was centred off the coast in Mounts Bay and people living across West Cornwall reported feeling the quake.
One person described it as "a low deep rumble" and another said "the whole house vibrated".
Another resident said they felt "a bang and a judder, like a juggernaut had hit the house."
The British Geological Survey said it received reports from residents in Helston, Penzance and Camborne. Most of the reports were from within 20 miles of the epicentre.
It has appealed for anyone who felt the quake to fill out an Earthquake Report, to help seismologists understand more about the event.
It has also published a seismogram showing the velocity of the quake.