A large earthquake that struck in the sea off Shetland at the weekend was the largest recorded in the UK for nine years.
The British Geological Survey said it was felt by more than 30 people more than 130 miles away from the epicentre.
The 4.4 magnitude tremor has now been upgraded to 4.7 following further analysis on the quake.
It was recorded in the northern North Sea, and the largest since a 5.2 tremor on land at Market Rasen, Lincolnshire in 2008.
The epicentre was around 131 miles south-east of Lerwick and happened at 1.33pm on Friday.
BGS seismologist Davie Galloway was in Shetland at the time and said “at least” 20 people there said they had felt it.
He said the epicentre was approximately 62 miles south-west of a magnitude 5.7 event in the Viking Graben in 1927.
The quake was felt in Lerwick and Sumburgh on Shetland; Kirkwall and Sanday in Orkney; in Wick and Thurso in Caithness and even Fraserburgh in Aberdeenshire.
One resident of Kirkwall, Orkney, said: “Very brief vibration of whole building. I am on the second upper floor.”
There have been a number of tremors over Scotland in the last few months as the Earth’s crust moves under pressure.
In April another earthquake struck in the sea off Shetland.
A 1.7 magnitude tremor was then recorded 124 miles south east of Lerwick.
The largest known Scottish earthquake occurred near Loch Awe in 1880, with a magnitude of 5.2.
There are roughly 200 to 300 quakes in Britain every year, but the vast majority are so small that no one notices them. However only between 20-30 are over 2.0 magnitude which can be felt over a wider area.
The most damaging UK earthquake was in the Colchester area in 1884. Some 1,200 buildings needed repairs, chimneys collapsed and walls were cracked.