The UK is not generally associated with earthquakes, however, between twenty to thirty earthquakes are felt by people each year, and a few hundred smaller ones are recorded by sensitive instruments. Most of these are very small and cause no damage. However, some British earthquakes have caused considerable damage, although nothing like the devastation caused by large earthquakes in other parts of the world.
The Largest
The largest known British earthquake occurred near the Dogger Bank in 1931, with a magnitude of 6.1. Fortunately, it was 60 miles offshore but was still powerful enough to cause minor damage to buildings on the east coast of England. The most damaging UK earthquake was in the Colchester area in 1884. Some 1200 buildings needed repairs, chimneys collapsed and walls were cracked.
How often? - How large?
A magnitude 4 earthquake happens in Britain roughly every two years. We experience a magnitude 5 roughly every 10-20 years. Research suggests that the largest possible earthquake in the UK is around 6.5.
Where do they occur?
A map of earthquake activity in the UK shows a number of regional variations. Most earthquakes occur on the western side of the British mainland. Earthquakes are almost completely absent from eastern Scotland and north east England. Similarly, Ireland is almost completely free of earthquakes. The North Sea is more active than the mainland.
Why do we get earthquakes in Britain?
The Earth under our feet has many faults caused by our turbulent geological past. Some of these faults can be observed at the surface and mapped by geologists, others are hidden many kilometres below the surface. These faults are places where earthquakes can occur. The driving forces for earthquake activity in the UK are unclear; however they include regional compression caused by motion of the Earth’s tectonic plates, and uplift resulting from the melting of the ice sheets that covered many parts of Britain thousands of years ago.
Historical seismicity of the UK (yellow) from 1832 to 1970 for earthquakes of magnitude above 3.0 and instrumental seismicity (red) from 1970 to present for earthquakes with ML >2.0.
Significant Earthquakes in the UK, 1932-present
Red circles show instrumentally recorded earthquakes. Yellow circles show historical earthquakes.
