Saturday 21 July 2018

Magnitude 1.1 Earthquake beneath Caernarfon Bay, North Wales.

The British Geological Survey recorded a Magnitude 1.1 Earthquake at a depth of about 12 km, beneath Caernarfon Bay on the coast of Gwynedd, North Wales, slightly before 11.00 pm British Summertime (slightly before 10.00 pm GMT) on Wednesday 18 July 2018. There are no reports of any damage or casualties associated with this event, and nor would they be expected with an Earthquake this small, but the quake was felt in Caernarfon, Talysarn, Llanfaelog and Cwm-y-glo.
 
The approximate location of the 18 July 2018 Caernarfon Bay Earthquake. 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.

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.
 
(Top) Simplified diagram showing principle of glacial rebound. Wikipedia. (Bottom) Map showing the rate of glacial rebound in various parts of the UK. Note that some parts of England and Wales show negative values, these areas are being pushed down slightly by uplift in Scotland, as the entire landmass is quite rigid and acts a bit like a see-saw. Climate North East.
 
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. 

See also...

https://sciencythoughts.blogspot.com/2017/10/dozens-of-octopus-crawl-up-welsh-beach.htmlhttps://sciencythoughts.blogspot.com/2015/12/magnitude-15-earthquake-in-gwynedd.html
https://sciencythoughts.blogspot.com/2015/08/magnitude-12-earthquake-on-lleyn.htmlhttps://sciencythoughts.blogspot.com/2015/05/magnitude-30-earthquake-off-coast-of.html
https://sciencythoughts.blogspot.com/2014/12/two-rescued-from-disused-mine-in.htmlhttps://sciencythoughts.blogspot.com/2014/08/magnitude-10-earthquake-in-gwynedd.html
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