Tuesday, 1 July 2014

Series of Earthquakes off the Isle of Arran.

The British Geological Survey recorded a series of three Earthquakes about 10 km off the south coast of the Isle of Arran in southwest Scotland on Saturday 28-Sunday 29 June 2014. The first event happened slightly after 11.50 am British Summertime (slightly after 10.50 am GMT) on Saturday 28 June, and had a Magnitude of 1.8. The second occurred at about 4.20 pm British Summertime (about 3.20 pm GMT) on the same day and had a Magnitude of 1.7. The third occurred slightly before 5.50 am on Sunday 29 June and had a Magnitude of 1.9. All occurred at a depth of about 7 km. These were not large events, and there is no danger of any damage or casualties, in fact given the distance from the nearest shore it is very unlikely that they were felt at all.

The approximate location of the 28-29 June 2013 Arran Earthquakes. Google Maps.

Earthquakes become more common as you travel north and west in Great Britain, with the west coast of Scotland being the most quake-prone part of the island and the northwest of Wales being more prone  to quakes than the rest of Wales or most of England.

The precise cause of Earthquakes in the UK can be hard to determine; the country is not close to any obvious single cause of such activity such as a plate margin, but is subject to tectonic pressures from several different sources, with most quakes probably being the result of the interplay between these forces.

Britain is being pushed to the east by the expansion of the Atlantic Ocean and to the north by the impact of Africa into Europe from the south. It is also affected by lesser areas of tectonic spreading beneath the North Sea, Rhine Valley and Bay of Biscay. Finally the country is subject to glacial rebound; until about 10 000 years ago much of the north of the country was covered by a thick layer of glacial ice (this is believed to have been thickest on the west coast of Scotland), pushing the rocks of the British lithosphere down into the underlying mantle. This ice is now gone, and the rocks are springing (slowly) back into their original position, causing the occasional Earthquake in the process. 

See also...

The British Geological Survey recorded a Magnitude 1.3 Earthquake...

A Magnitude 1.7 Earthquake at a depth of 2 km took place on the Rinns of Islay (the southwest peninsula of the Isle of Islay) at about 9.20 pm British Summertime (about 10.20 pm GMT) on...

On Wednesday 31 October 2012, slightly before 4.00 pm GMT, the British Geological Survey recorded a Magnitude 2.7 Earthquake 7 km beneath the Isle of Jura, south of Loch a' Gharbh-uisge and...

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