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Fault buried under drift strata
Geological fault buried under drift

In this geological cross-section, fault 'F' separates strata 'A' from 'B'. However, the fault is buried under drift deposit 'C'. Drift deposits are strata overlaying bedrock left by glaciation, rivers or landslides. Since the fault is effectively buried, possibly hundreds of meters down, it may not be as close as you thought to the site of interest above (shown as a building here).

Investigation technique pages
Analysing cold spots
Doors that open by themselves
The 'new house effect'
Vigils in the dark?
Why use science?
What approach to investigation?
Paranormal words
What is a haunted place?
Paranormal activity or nature?
Is my house haunted?
Science applied to paranormal
Geology and ghosts
Paranormal & science theories
Geomagnetism in the paranormal
Using people on vigils
Science for investigators
Paranormal sounds
Recording EVP
Evidence is everything!


Magnetism is thought by many to be the main connection, if indeed there is one, between geology and paranormal reports.

Magnetism varies from place to place across the Earth's surface. As well as temporary changes to geomagnetic field, there are permanent local variations caused by geology. Essentially, where there are magnetic minerals (such as magnetite) underground, they will alter the local magnetic field. You can find local magnetic anomalies on aeromagnetic maps, available from geological survey organisations.

There are, however, important points to bear in mind. Local geological magnetic anomalies, though they might produce interesting anomalous effects (such as deflecting compass needles), are static disturbances. Generally, the kind of magnetic fields thought to be associated with ghosts and other paranormal phenomena are varying.

Another point to bear in mind is that geological magnetic anomalies are not strong (a difference of 150 nT compared to the surrounding areas would be considered extreme). There are likely to be larger magnetic distortions within a building due to the presence of metals like steel or iron.

Magnetic anomalies are often associated with the rare phenomenon of free wheeling cars apparently running uphill (like Magnetic Hill on the Isle of Wight). However, this anomaly is thought to be an optical illusion caused by unusual perspective rather than any magnetic (or indeed gravity) anomaly.


Geology and the paranormal

One of the factors that paranormal researchers often look at these days is the geology of an area where something weird has been reported. This is particularly so with ghosts, which appear repeatedly in the same place. Some researchers have suggested there could be a link between paranormal reports and geology. Even without such ideas, geology is always worth recording, since no one knows exactly what causes haunting. Given that hauntings are place-related, geology is one of many geographical factors to consider.

Tectonic strain theory

The most popular idea linking geology and reports of the paranormal is the Tectonic Strain Theory. Essentially, the Tectonic Strain Theory (TST) states that stresses within the Earth’s crust, less than those required to produce an earthquake, may result in highly localised surface electromagnetic disturbances through piezoelectricity (or some other mechanism) in sub-surface rocks. Piezoelectricity is the phenomenon whereby certain crystals, notably quartz, produce an electric charge across opposite crystal faces when under physical pressure or strain.

It is hypothesised that the electric and magnetic fields produced by such rock strain will be commonest near geological faults (see right). These cracks in the Earth's crust are, like cracks in most objects, signs of strain and movement.

Quartz generally occurs underground within other rocks, like granite. The quartz crystals are separated from each other by other minerals. If you crush granite, an electric charge will build up across individual quartz crystals. However, since the crystals are orientated randomly, the electric charges (which occur on opposite sides of each crystal) do not align. Therefore, they tend to cancel each other out rather than combining to form a strong overall electric field. So simple strain seems unlikely to produce significant electromagnetic fields above ground through piezoelectricity. If the rocks actually fracture, however, during an earthquake for instance, you well might get electromagnetic fields produced by seismoelectric conversion. Some earthquakes have indeed been accompanied by weak but measurable magnetic disturbances.

A scientist called Friedemann Freund has suggested that electric charges could be induced to flow by applying unusual pressure (through tectonic stress) to igneous rocks (normally insulators) turning them into semi-conductors. When the rocks are turned temporarily into semiconductors, holes (positively charged discontinuities) can flow rapidly through the rocks and might even reach the surface. The charges are conducted around underground both by rocks, in their semi-conductor state, and by water. This may be the mechanism behind earthquake lights. The theory is still being developed but it looks promising.

Field researchers are therefore advised to examine local geology (particularly the presence of faults and igneous rocks, such as granite, diorite, gabbro, basalt, etc.) thoroughly in their investigations and see if any magnetic disturbances detected can be traced to an underground source.

For more on the tectonic strain theory, see this study.


Geological faults

The main geological feature that gets paranormal researchers excited is the fault. A fault is fracture in the local rock strata. It is effectively a crack along which rock strata move. This does not mean that you would necessarily see a big crack if you actually saw a fault (though sometimes you can, in cliff faces, for instance).

The movement along faults is caused by tectonic forces (such as tectonic plates moving). Faults are not usually a clean single line but an area of compressed rock (where rocks have moved or are under extreme pressure) on either side of the line, called a fault zone.

The reason why paranormal researchers are interested in faults is partly because of rare (anomalous) phenomena called earthquake lights but mostly because of the Tectonic Strain Theory (see left).

As with anything technical in paranormal research, you need to know your subject (in this case, geology) before you can pronounce on its part in the paranormal.

Faults do not generally follow topographical features so the only way to reliably identify them is with a geological map. You'll need one of reasonably large scale (eg. 1:50 000) to see if faults are near the site you are investigating. You should note that geological maps come in two main varieties - solid and drift. The important point to bear in mind is that a fault may be covered by a drift deposit (see figure and caption, left) so that it may be covered by tens or hundreds of meters of rock, making it further away (in the vertical plane) than you might see from the map.

When looking for faults, make sure you use a drift map and look for cross-sections showing the depth of drift deposits. You may also need to consult geological memoirs for the area. Bear in mind that electromagnetic fields fall off rapidly with distance.

Radon gas

Another possible connection between the paranormal and geology is radon gas. This radioactive element is produced from rocks below ground and is found almost everywhere. Radon is one of the main producers of air ions.

Some paranormal researchers have found radiation anomalies associated with hauntings though the evidence so far is slight. Much such excess radiation is associated with radon. Radon is most common in areas with granite. It accumulates in buildings without draughts because it is heavier than air.

© Maurice Townsend 2006