Residents across Perthshire and Stirlingshire recently experienced a notable series of seismic events, with multiple earth tremors registered throughout the region. This activity included two distinct earthquakes, both exceeding three in magnitude, occurring on Monday at approximately 7 am and again just after 5 pm. These tremors were specifically logged near Pubil, in the vicinity of Loch Lyon, causing widespread discussion and curiosity among the local populace.
The occurrence of earthquakes, while generally mild, is not an entirely unfamiliar phenomenon in this part of Scotland. Indeed, the town of Comrie holds a unique place in seismic monitoring, being home to the historic Earthquake House. Established in 1874, this specialised structure was built to house a seismoscope – an instrument designed to detect and record ground movements – and has been diligently tracking earth activity for well over a century, providing invaluable data on local and global tremors. Understanding Seismic Activity in the UK
Earthquakes originate from the abrupt release of accumulated energy along fracture zones, known as faults, deep within the Earth’s crust. This sudden movement generates vibrational waves that propagate outwards, resulting in the ground shaking that people experience. The British Geological Survey (BGS), which acts as the national authority for earthquake monitoring in the UK, reports that approximately 200 to 300 seismic events are detected across the country each year.
While the United Kingdom is situated far from major tectonic plate boundaries, such as the prominent Mid-Atlantic Ridge, internal stresses within these massive crustal plates can build over time. When these stresses reach a critical point, they are relieved through movement along pre-existing weaknesses or faults in the bedrock, leading to the earthquakes we observe, even far from the edges of plates. Why Perthshire and Stirlingshire are Seismically Active
In Perthshire and Stirlingshire, the BGS attributes these tremors to minor shifts occurring along ancient geological faults embedded within the Earth’s crust. Given that these localised movements are typically small and occur several kilometres beneath the surface, pinpointing their exact origin and correlating them with specific faults visible on surface geological maps presents a considerable challenge for geologists.
Historical records from the Perth and Kinross Heritage Trust offer insight into potential causes, suggesting a possible link to the Highland Boundary Fault (HBF). This ancient geological feature was highly active almost 400 million years ago. Historically, experts had speculated that the HBF was directly responsible for seismic activity in areas like Comrie. However, further examination indicates that some past earthquake epicentres were located to the north of Comrie, rather than south where the known trace of the HBF is located. This raises the intriguing possibility that the region’s tremors could stem from a complex network of smaller, potentially buried faults north of Comrie, a geological puzzle that continues to be investigated by researchers. The Impact of Local Earthquakes
The recent tremors on Monday were widely felt throughout Perthshire and Stirlingshire, extending their reach to communities such as Aberfeldy, Kenmore, Rannoch, and Killin. Residents described experiencing a distinct ‘swaying’ sensation, with one person likening it to the feeling of ‘an underground subway passing beneath my house.’ Alongside the two larger quakes (magnitudes 3.6 and 3.7), several smaller, less perceptible tremors were also recorded on Monday, with further minor activity continuing into Tuesday morning.
To put this in perspective, the largest recorded earthquake in Scottish history was a magnitude 5.4 event in Argyll, which was felt extensively across the entire country. The energy released by the most significant of Monday’s quakes was approximately 400 times less powerful than this historic event, highlighting the relatively low intensity of the recent tremors. Local memory recalls other periods of heightened seismic activity, including September and November 2020, when 29 earthquakes were noted near Blackford, with nine of these being felt by residents in Blackford itself, as well as in nearby Gleneagles and Auchterarder. On average, the UK experiences about three earthquakes of magnitude three or greater annually, with more significant tremors of magnitude four or higher occurring less frequently, typically every two to three years. Historical Perspective on Perthshire’s Earthquakes
The overall earthquake hazard in the UK remains low, and incidents causing significant structural damage are exceedingly rare. However, historical records do indicate instances of minor damage, such as dislodged chimneys and cracks in buildings, resulting from past seismic events. A magnitude 5.1 earthquake in Inverness in 1901, for example, reportedly caused ‘substantial’ minor damage, though events of this scale are considered exceptional.
Comrie has a particularly rich seismic history, having experienced ‘swarms’ of earthquakes during the periods of 1788-1801 and 1839-1846. The most powerful of these was a magnitude 4.8 quake in October 1839, which was even linked to a breach of the Earl’s Burn dam near Stirling. Similar sequences of closely spaced tremors, or ‘swarms,’ have been documented in other local areas. These include Glenalmond between 1970 and 1972, Doune in 1997, multiple events near Blackford in 1997, 1998, 2000, 2001, and 2020, and Aberfoyle in 2003. Notably, a 3.2-magnitude earthquake in 1979 was widely felt and is reported to have caused damage to the Glen Devon dam in the Ochil Hills. The frequent, though mostly minor, seismic activity underscores the dynamic geological character of Perthshire and Stirlingshire.
The occurrence of earthquakes, while generally mild, is not an entirely unfamiliar phenomenon in this part of Scotland. Indeed, the town of Comrie holds a unique place in seismic monitoring, being home to the historic Earthquake House. Established in 1874, this specialised structure was built to house a seismoscope – an instrument designed to detect and record ground movements – and has been diligently tracking earth activity for well over a century, providing invaluable data on local and global tremors. Understanding Seismic Activity in the UK
Earthquakes originate from the abrupt release of accumulated energy along fracture zones, known as faults, deep within the Earth’s crust. This sudden movement generates vibrational waves that propagate outwards, resulting in the ground shaking that people experience. The British Geological Survey (BGS), which acts as the national authority for earthquake monitoring in the UK, reports that approximately 200 to 300 seismic events are detected across the country each year.
While the United Kingdom is situated far from major tectonic plate boundaries, such as the prominent Mid-Atlantic Ridge, internal stresses within these massive crustal plates can build over time. When these stresses reach a critical point, they are relieved through movement along pre-existing weaknesses or faults in the bedrock, leading to the earthquakes we observe, even far from the edges of plates. Why Perthshire and Stirlingshire are Seismically Active
In Perthshire and Stirlingshire, the BGS attributes these tremors to minor shifts occurring along ancient geological faults embedded within the Earth’s crust. Given that these localised movements are typically small and occur several kilometres beneath the surface, pinpointing their exact origin and correlating them with specific faults visible on surface geological maps presents a considerable challenge for geologists.
Historical records from the Perth and Kinross Heritage Trust offer insight into potential causes, suggesting a possible link to the Highland Boundary Fault (HBF). This ancient geological feature was highly active almost 400 million years ago. Historically, experts had speculated that the HBF was directly responsible for seismic activity in areas like Comrie. However, further examination indicates that some past earthquake epicentres were located to the north of Comrie, rather than south where the known trace of the HBF is located. This raises the intriguing possibility that the region’s tremors could stem from a complex network of smaller, potentially buried faults north of Comrie, a geological puzzle that continues to be investigated by researchers. The Impact of Local Earthquakes
The recent tremors on Monday were widely felt throughout Perthshire and Stirlingshire, extending their reach to communities such as Aberfeldy, Kenmore, Rannoch, and Killin. Residents described experiencing a distinct ‘swaying’ sensation, with one person likening it to the feeling of ‘an underground subway passing beneath my house.’ Alongside the two larger quakes (magnitudes 3.6 and 3.7), several smaller, less perceptible tremors were also recorded on Monday, with further minor activity continuing into Tuesday morning.
To put this in perspective, the largest recorded earthquake in Scottish history was a magnitude 5.4 event in Argyll, which was felt extensively across the entire country. The energy released by the most significant of Monday’s quakes was approximately 400 times less powerful than this historic event, highlighting the relatively low intensity of the recent tremors. Local memory recalls other periods of heightened seismic activity, including September and November 2020, when 29 earthquakes were noted near Blackford, with nine of these being felt by residents in Blackford itself, as well as in nearby Gleneagles and Auchterarder. On average, the UK experiences about three earthquakes of magnitude three or greater annually, with more significant tremors of magnitude four or higher occurring less frequently, typically every two to three years. Historical Perspective on Perthshire’s Earthquakes
The overall earthquake hazard in the UK remains low, and incidents causing significant structural damage are exceedingly rare. However, historical records do indicate instances of minor damage, such as dislodged chimneys and cracks in buildings, resulting from past seismic events. A magnitude 5.1 earthquake in Inverness in 1901, for example, reportedly caused ‘substantial’ minor damage, though events of this scale are considered exceptional.
Comrie has a particularly rich seismic history, having experienced ‘swarms’ of earthquakes during the periods of 1788-1801 and 1839-1846. The most powerful of these was a magnitude 4.8 quake in October 1839, which was even linked to a breach of the Earl’s Burn dam near Stirling. Similar sequences of closely spaced tremors, or ‘swarms,’ have been documented in other local areas. These include Glenalmond between 1970 and 1972, Doune in 1997, multiple events near Blackford in 1997, 1998, 2000, 2001, and 2020, and Aberfoyle in 2003. Notably, a 3.2-magnitude earthquake in 1979 was widely felt and is reported to have caused damage to the Glen Devon dam in the Ochil Hills. The frequent, though mostly minor, seismic activity underscores the dynamic geological character of Perthshire and Stirlingshire.