North West Wales

Llyn Peninsula named in top 10 UK earthquake hotspots

Map of earthquakes in the UK Image copyright Esri UK
Image caption There are more than 100 seismograph stations across the UK which measure earthquakes

Gwynedd has been revealed as one of the UK's earthquake hotspots.

A new map published on National Richter Scale Day plots over 10,000 earthquakes that have happened in the UK since 1970.

The Llyn Peninsula has been named among the 10 most active areas, with almost 300 earthquakes recorded.

It is also the location of the biggest earthquake of the past 50 years, which was a 5.4 magnitude quake on 19 July 1984.

The map was created by Esri UK using British Geological Survey (BGS) data. It celebrates the birth of Charles Richter, the US investor of the Richter Scale, who died in 1985.

The scale was first published in 1935 and is used to measure the strength or magnitude of an earthquake after its vibrations are detected by a seismometer.

It ranges from 0-10, and the higher the number the more destruction likely.

Other places to make the top ten, which is not ranked in any particular order, include:

  • Edinburgh
  • Gweek, Cornwall
  • Clackmannan
  • Stoke-on-Trent
  • Mansfield
  • Manchester
  • Knoydart Peninsula
  • Dumfries
  • Blackpool

Across Wales, almost 900 earthquakes have been recorded since 1970.

Image copyright Esri UK
Image caption Plotted earthquakes on the Llyn Peninsular

The UK's largest known earthquake was on 7 June 1931 in the North Sea with a magnitude of 6.1. It was felt across most of the UK with damage reported in more than 70 locations.

An Esri UK spokesman said: "People often think that the UK rarely has earthquakes, but in reality there are a few hundred each year. Most are simply too small or deep for us to feel."

The BGS said seismicity distribution for mainland and offshore UK is "neither random nor uniform in density", with more frequent and larger events occurring on the west coast.

It said: "North Wales, especially around Caernarfon and the Llyn Peninsula, and the Welsh border area show higher levels of seismicity".

BGS seismologist Davie Galloway said the planet is made up of "plates jiggling around," and as the UK is sitting in the middle of one of those plates, it does not get many powerful earthquakes.

"But we are still affected by movement every now and then," he said.

He said the Llyn Peninsula was a hotspot as it is home to the most powerful onshore earthquake ever recorded in the UK in 1984.

"It is one of the most famous earthquakes in the UK and was felt as far as Edinburgh," he said.

He explained "hundreds of little earthquakes" or aftershocks happened in the area in the following years as a consequence of the 1984 quake.

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