IMAGES TAKEN NEAR TO
The Ross, CRIEFF, PH6 2JU

Looking down to Ross from the Earthquake House.

Towards the houses on The Ross.

On the Ross at Comrie.

Comrie stands close to the Highland Boundary Fault (HBF), a major geological feature in Scotland which separates the Highlands from the Central Lowlands or Midland Valley, and has long been famed as Scotland's earthquake capital. Interestingly, the interactive map of UK earthquakes on the BGS Website http://www.earthquakes.bgs.ac.uk/ does not imply that Comrie is an earthquake hotspot at all! The fact that the earthquakes are localised, rather than occurring with equal frequency right along the fault, suggests that they are not necessarily due to the HBF, and may be related to some other geological structure or feature not now visible on the ground. Interested people have been collecting information about the Comrie earthquakes since the latter half of the 18th century, information which is still useful for geological research in the 21st century. The 1840s saw the development of the seismoscope, an instrument which registered earthquakes. This was superseded by more sophisticated instruments capable of recording not just the occurrence and strength of an earthquake, but also the time, the exact location of its epicentre (the point on the surface of the Earth directly above the focus, which is the point in the Earth's crust at which displacement has occurred) and its depth in the crust. Earthquake House stands on a knoll in a field in the Ross, one of the three old settlements which make up the village of Comrie, the others being the village itself and Dalginross. It was built in 1874 and equipped with a seismoscope, but earthquake activity declined and it was never used. The building was neglected until 1986, when it was restored. It contains a model of the original instrument and a modern seismograph installed by the British Geological Survey.

Comrie stands close to the Highland Boundary Fault (HBF), a major geological feature in Scotland which separates the Highlands from the Central Lowlands or Midland Valley, and has long been famed as Scotland's earthquake capital. Interestingly, the interactive map of UK earthquakes on the BGS Website http://www.earthquakes.bgs.ac.uk/ does not imply that Comrie is an earthquake hotspot at all! The fact that the earthquakes are localised, rather than occurring with equal frequency right along the fault, suggests that they are not necessarily due to the HBF, and may be related to some other geological structure or feature not now visible on the ground. Interested people have been collecting information about the Comrie earthquakes since the latter half of the 18th century, information which is still useful for geological research in the 21st century. The 1840s saw the development of the seismoscope, an instrument which registered earthquakes. This was superseded by more sophisticated instruments capable of recording not just the occurrence and strength of an earthquake, but also the time, the exact location of its epicentre (the point on the surface of the Earth directly above the focus, which is the point in the Earth's crust at which displacement has occurred) and its depth in the crust. Earthquake House stands on a knoll in a field in the Ross, one of the three old settlements which make up the village of Comrie, the others being the village itself and Dalginross. It was built in 1874 and equipped with a seismoscope, but earthquake activity declined and it was never used. The building was neglected until 1986, when it was restored. It contains a model of the original instrument and a modern seismograph installed by the British Geological Survey.

OS Cut Mark, South angle, Rossbank House, North West Side of the Road (ODN 62.1792m, AGL 0.5m).

The small building resembling a summerhouse in the field was a pioneering scientific venture to measure earthquake tremors, built in 1874. Tremors had been felt in the area in the 1840s, leading to an initiative by the British Association for the Advancement of Science to test a number of instruments in and near Comrie capable of responding to earthquake movements. The building housed a 'seismoscope' consisting of several wooden cylinders of different diameters standing upright - a tremor would shake the cylinders sideways and topple them. The stronger the tremor, the larger would be the diameters that were knocked over. (Source - leaflet available at the Earthquake House) More on UK earthquakes is available at http://www.earthquakes.bgs.ac.uk/

This is a reconstruction of the early instrument for monitoring earthquake tremors installed in this purpose-built shelter in 1874. The wooden cross lies on a bed of sand to isolate it from nearby disturbance. On each arm are placed three wooden cylinders of the same height but different diameters. A tremor would cause one or more cylinders to topple, with only a strong tremor affecting the thickest cylinders. Hence the number and direction of cylinders knocked down and recorded in the sand would indicate strength and direction of a tremor. In fact, the earthquake activity of the 1840's did not recur, and the instrument never functioned. The building was restored from 1986 by Perth and Kinross Council with Perth and Kinross Heritage Trust and British Geological Survey. BGS maintain a modern seismometer, here visible as the metal cylinder at the top corner of the sand tray. The green colouration is due to reflection in the glass window through which the photograph was taken.

With a fine Scot's Pine.