Wednesday 11 September 2013

Magnitude 1.6 Earthquake in northwest Argyll and Bute.

The British Geological Survey recorded a Magnitude 1.6 Earthquake at a depth of 7 km in northwest Argyll and Bute County, Scotland, slightly after 9.50 pm British Summertime (slightly after 8.50 pm GMT) on Monday 9 September 2013. A quake this small is unlikely to have caused any damage or injuries, but may have been felt locally.

The approximate location of the 9 September 2013 Argyll and Bute Earthquake. Google Maps.

As a rough rule of thumb, when you travel further to the north and west in Great Britain Earthquakes become more frequent, making Scotland (in particular western Scotland) the most quake prone area of the country. The precise causes of British Earthquakes can be hard to determine, as the country is not close to any active plate boundary, but is subject to tectonic stresses from a number of different sources.

Scotland (along with the rest of Eurasia) 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. Closer to home there are lesser centers of expansion beneath the North Sea, the Rhine Valley and the Bay of Biscay, all of which excerpt pressure on Scottish rocks. Finally there is glacial rebound; until about 10 000 years ago much of the UK was covered by a thick layer of ice, pushing the rocks of the lithosphere down into the underlying mantle; this ice is now gone and the rocks are (slowly) rebounding, causing the occasional Earthquake in the process.

Witness accounts of Earthquakes can help geologists to understand these events, and the structures that cause them. If you felt this quake, or were in the area but did not (which is also useful information) then you can report it to the British Geological Survey here.

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