Friday 12 October 2012

Earthquake in Nottinghamshire.

On Wednesday 10 October 2012, slightly before 10.30 am, British Summertime (slightly before 9.30 am, GMT), the British Geological Survey recorded a Magnitude 1.6 Earthquake 1 km beneath the Nottinghamshire village of Ollerton. Earthquakes of this Magnitude are far too small to cause any damage or casualties, and often pass unnoticed by the local population, though on this occasion several people in the village did apparently report feeling the quake.

Map showing the location of the 10 October Earthquake. Google Maps.

Most UK Earthquakes are the result of the interaction of tectonic stresses from a number of different sources, rather than any one single factor. There have been a number of quakes in the Nottinghamshire area this year, suggesting that stresses beneath the county are causing some realignment of the rocks there, though this is unlikely to result in any particularly large events (confusingly there have also been quakes around the Cheshire village of Ollerton).

Britain (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. In addition there are smaller areas of tectonic expansion beneath the North Sea, the Rhine Valley and the Bay of Biscay, all of which lead to some stress on UK rocks. Finally there is glacial rebound; until about 10 000 years ago much of the north of Britain was covered by a thick layer of glacial ice, which pushed the rocks of the British Lithosphere down into the underlying mantle. This ice is now gone, and the rocks are rebounding (at geological speeds) causing the occasional Earthquake in the process.

Witness accounts can help geologists to understand the processes going in during Earthquakes and subsequently the rock structures that cause them. If you felt this quake (or if you were in the area but didn't, which is also useful information) then you can report it to the BGS here.

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