Tuesday 19 March 2013

Earthquake in Norfolk.

On Saturday 16 March 2013, slightly after 7.00 am GMT, the British Geological Survey recorded a Magnitude 2.1 Earthquake in Norfolk, roughly 30 km southwest of Norwich, at a depth of 4 km. This is not a large enough magnitude to have caused any serious damage, but it is large enough that it may have been felt locally.

The location of the 16 March 2013 Earthquake. Google Maps.

The precise cause of earthquakes in the UK can be hard to determine. The country is not located close to any single large source of tectonic activity, so that most quakes are probably the result of the interaction of a number of stresses. 

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. There are also smaller but more local centers of tectonic expansion beneath the North Sea, Rhine Valley and Bay of Biscay, all of which exert some stress upon rocks in the UK. Finally there is glacial rebound; until about 10 000 years ago much of the north of the UK was covered by a thick layer of glacial ice, which pushed the rocks of the lithosphere down into the underlying mantle. This ice is now gone, and the rocks are slowly springing back into there original position, causing the occasional Earthquake in the process.

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

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