Wales' history of earthquakes

A map of the location of the earthquake Wednesday's minor earthquake measured 3.8 on the Richter scale

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Experts say north Wales is a "seismically active" part of the UK, which makes it prone to more earthquakes.

The largest earthquake ever recorded in the UK happened on the Llyn Peninsula, Gwynedd, in 1984.

It measured a moderate 5.4 on the Richter scale and caused damage across north Wales and tremors could be felt across the UK.

Wednesday's minor earthquake measured 3.8.

What made the 1984 earthquake so unusual was the fact that it began at a depth of over 20km (12 miles) and created a shock wave that could easily have caused major structural damage.

The British Geological Survey (BGS) said smaller quakes are not unusual in Wales.

Seventy measuring more than 3.5 happened between 1727 and 1984.

Putting Wednesday's earthquake into perspective, Brian Baptie, seismologist for the BGS, told BBC Radio Wales: "We get an earthquake of this size somewhere in the UK maybe once of twice every couple of years.

Richter scale

Less than 2.0 - a micro earthquake and not felt

2.0 - 3.9 - minor earthquake, sometimes felt, no damage

4.0 -4.9 - light earthquake, noticeable shaking, no damage

5.0 - 5.9 - moderate, minor damage

6.0 - 6.9 - strong, can be destructive

7.0 - 7.9 - major, serious damage over large areas

8.0 - 8.9 - great, serious damage over hundreds of miles

9.0 - 9.9 - great, devastating areas over thousands of miles

10.0+ - epic, never recorded

Source: US Geological survey

"We also know that north Wales is one of the more seismically active parts of the UK, it's got a long history of small earthquakes in the past few hundred years," he said.

The earliest recording of an earthquake in Wales was in 1247 in Pembrokeshire.

The tremors were so severe the edifice of St Davids Cathedral was damaged.

In Caernarfon in 1690, the first recorded earthquake happened and tremors were felt in London. Two months earlier, Carmarthen was also hit.

In 1852 Caernarfon was hit again but a quake in Swansea in 1906 measured 5.2 and is still regarded as one of the most significant of all British earthquakes. Certainly it caused major damage to property.

The only death from a UK earthquake happened on 12 December 1940 in north Wales. An elderly woman lost her balance and fell down the stairs of her home.

The last earthquake to hit Wales happened around Caernarfon in February 2013 and measured a minor 2.3 on the Richter scale.

The tremor was also felt in Anglesey, Porthmadog and Bangor. Reports said it caused houses to shake and was "like a lorry crashing into the house".

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