Two minor earthquakes were recorded in Wales on Wednesday, according to the British Geological Survey (BGS). The tremors struck in Powys and Gwynedd, with magnitudes of 1.1 and 1.3 respectively.
Details of the Tremors
The first quake hit Llangynidr, near Crickhowell, in Powys, at 3.22am on August 12. It registered 1.1 on the Richter scale at a depth of 6km.
The second earthquake was detected in the afternoon near Bontddu, on the northern banks of the Mawddach Estuary in Gwynedd, at 1.30pm. This tremor was slightly more powerful at 1.3 on the Richter scale, with a depth of 8km.
Seismic Context
It remains unclear whether either tremor was felt locally. Most quakes measuring below 2.5 on the scale go unnoticed but are picked up by seismographs, experts say.
Locations and magnitudes may be subject to change as events are re-examined and revised. The BGS documents approximately 300-400 earthquakes each year across Britain.
Wales' Seismic Activity
Wales, along with the rest of the UK, sits on the European plate. Pressure accumulates as the plate is gradually pushed north-eastwards from the Mid-Atlantic Ridge, and this pressure is discharged through movement along existing fault lines, triggering earthquakes.
The Menai Strait area remains the most seismically active region in Wales and among the most active in the UK. The magnitude 5.4 earthquake of 1984 was the most powerful onshore seismic event to strike the UK in more than a century, with its epicentre along the northern coastline of the Llŷn Peninsula at a depth of around 22km.
