On Saturday 6 October 2012 at 1.30 pm, British Summertime (12.30 pm, GMT), the British Geological Survey recorded a Magnitude 1.1 Earthquake 2 km beneath the Scottish village of Johnstonebridge, roughly 20 km northeast of Dumfries, or 40 km northwest of Carlisle. Earthquakes of this magnitude are highly unlikely to cause any damage or casualties, and quite often go unnoticed by the local population, as seems to have been the case with this event.
The location of the 6 October 2012 Earthquake. Google Maps.
The UK is not noted for its Earthquake activity, but small quakes of this kind are not uncommon, and tend to become more frequent as you move north and west, making the west of Scotland the most quake-prone part of the country.
There is no single cause to which Scottish Earthquakes can easily be attributed, but rather the country is subject to tectonic stresses from a variety of sources, with most quakes being the result of tectonic stresses from a variety of 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. There are also lesser areas of tectonic spreading beneath the Rhine Valley, the North Sea and the Bay of Biscay, all of which will excerpt stress upon British rocks. In addition there is glacial rebound; until about 10 000 years ago much of northern Europe, including most of Scotland, was covered by a thick layer of glacial ice, which pushed the rocks of the Scottish lithosphere down into the underlying mantle. This ice is now gone, and the rocks are still slowly rebounding, causing the occasional Earthquake in the process.
Witness statements can help geologists to understand the movements during Earthquakes and therefore the structures that cause them. If you felt this quake (or if you were in the area but did not, which is also useful information), then you can report it to the British Geological Survey here.
See also Two Earthquakes in Perthshire in two days, Small Earthquake in the Western Highlands, Earthquake in County Donegal, Small Earthquake on Islay, Argyle and Bute and Earthquakes on Sciency Thoughts YouTube.
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