Category: Events



Introduction and description

Infrasound, sometimes referred to as low-frequency sound, is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing.Thus this section describes the event of a person being exposed to infrasound.  It would not be correct to say 'hearing' infrasound, as generally speaking people cannot hear infrasound.

Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing infrasound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.

The study of such sound waves is sometimes referred to as infrasonics, covering sounds beneath 20 Hz down to 0.1 Hz and rarely to 0.001 Hz. People use this frequency range to monitor earthquakes, chart rock and petroleum formations below the earth, and also in ballistocardiography and seismocardiography to study the mechanics of the heart. 

Infrasound is characterized by an ability to get around obstacles with little dissipation. In music, large pipe organs or, for reproduction, exotic loudspeaker designs such as subwoofers can produce low-frequency sounds, including near-infrasound. Subwoofers designed to produce infrasound are capable of sound reproduction an octave or more below that of most commercially available subwoofers, and are often about 10 times the size.

All of which is somewhat disturbing as infrasound is able to give people hallucinations, it can damage cells and organs and it can kill.  The intensity and the distance from the source is key, as at low intensity and from far away, infrasound will shake your organs and may induce hallucinations.  But near to and at high intensity it can shake your organs so much it can damage them.  The water in your cells resonates to the sound, as such it is similar to the effect produced when you rub your finger round a glass of water.  Occasionally you can break the glass.

Sources of infrasound

Rather than group the sources of infrasound in one large mass under this heading, we have separated them out on th esite and given them each an explanatory description, but in brief the main sources of infrasound are:

Solar flares

Solar flares produce infrasound.  One of the ways in which we know this is through the work of the University of Alaska at Fairbanks who have been monitoring the effects of auroral activity via an array of infrasound detector stations – see Auroras and University of Alaska.


An avalanche starts when an unstable mass of snow breaks away from a mountainside and moves downhill. It picks up speed as it rushes down the mountain, and may also pick up ice, soil, rocks and uprooted trees. Some reach speeds of 245 mph. And in doing so they often create infrasound.

Acoustic non lethal weapons

Occasional Paper No. 1; The Early History of “Non-Lethal” Weapons - Neil Davison
December 2006,  Bradford Non-Lethal Weapons Research Project (BNLWRP)
Department of Peace Studies, University of Bradford, UK

In 1973 the International Committee of the Red Cross (ICRC) published a report drawing attention to certain weapons, including laser weapons, ....and subsequently convened two meetings of government experts in Switzerland under the name Conference of Government Experts on Weapons which May Cause Unnecessary Suffering or have Indiscriminate Effects. The first meeting was held in Lucerne in 1974 and the second in Lugano in 1976. Primarily the meetings addressed certain conventional weapons such as incendiary weapons and cluster bombs, however brief reference was also made to new weapons that didn’t fit into categories such as ‘conventional’ or ‘chemical’. Many of these were technologies that would become relevant to proposed “non-lethal” weapons including

  • directed energy (specifically laser and microwave devices),
  • acoustic (specifically infrasound devices), and
  • optical (specifically light-flash or stroboscopic devices).

Sonic weapons

Sonic weapons (USW)  are weapons that use sound to injure, incapacitate, or kill an opponent. They can be both infrasound based and ultrasound based.  Those based on ultrasound kill a person like a microwave might by resonating the water in their cells until it boils.  Infrasound weapons principally affect the brain and resonate the organs in the brain disrupting the entire biological system. 
The U.S. DOD has actually demonstrated phased arrays of infrasonic emitters. The weapon consists of a device that generates sound at about 7 Hz. The output from the device is routed (by pipes) to an array of open emitters. At this frequency, armor and concrete walls and other common building materials allow sound waves to pass through, providing little defense.


Minesweepers use infrasound to detect mines and there have been a number of reports that suggest that the use of infrasound affects the crew.

Violent weather - thunder, wind and rain

Violent weather – wind, rain thunder – all produce sound and sound is a mechanical stimulant to our bodies if we are out in that storm.  If you happen to be by the seashore, even better because the crashing surf and rolling waves also produces considerable sound.  Violent weather produces a whole spectre of sound going from high frequency audible to low frequency inaudible sound.

It has only recently been established that severe weather produces infrasound, sound that can be experienced thousands of miles away – for more details see   Storms and infrasound and the Observations.

Large scale subwoofer speakers

A subwoofer is a loudspeaker capable of reproducing low pitched audio frequencies.  The typical frequency range for a subwoofer is about 20–200 Hz for consumer products, but there are many notable exceptions which produce sound in the infrasound range.  They were originally designed to augment woofers that only covered audible and higher frequency ranges, but have taken on a life of their own, because the very deep bass notes they produce are "loved by concert goers and home audio system listeners alike".  Although this is presumably because they don't know the long term effects.

Binaural beats and hemi-sync

This is targeted sound as one can listen to it through headphones and there is a fair amount of science behind the scenes in the frequencies employed.  It is low intensity sound.  There is an inherent risk in using the technology because the size of people's organs in the brain may be different and you could over stimulate the wrong ones.  If you go to a reputable provider, however,  it is likely to be safer.  Note that this is the only source on this list which is targeted to specific frequencies and to specific organs in the brain, as such it is the only ‘semi-reliable’ technique

Obelisks, standing stones, mark stones, rock gongs, stalagtites, stalagmites and other lithophones

Some rocks, especially granite ones, can produce musical sounds when struck with another smaller rock. The technical name for these sorts of stones is a ‘lithophone’, they are often found in sacred places – such as temples and other sites of worship such as henges.

It is rarely understood that columns and obelisks might have been made from granite or other rock known to be capable of producing sound. Not all columns do, not all obelisks do, but there are some that quite definitely were chosen for this purpose.  And sometimes one can hear the sound and sometimes one cannot, because it is infrasound.  For example, there is a fallen obelisk in the great temple complex of Karnak in Luxor that if struck near its pyramidical point and the ear is placed close to this point can be just about heard to resonate.

The ruined city of Jeresh in Jordan contains a set of lithophones whose tones are scaled. The site of Jeresh has been occupied since Neolithic times and the lithophones have been incorporated into the architecture of the city with its paved colonnades, plazas, towers and gates.


Explosions of all sorts, mining explosions, bombs, nuclear explosions, rocket explosions, accidental explosions such as factory explosions, crashes, even the explosion of volcanoes all create sound and, most notably, infrasound and can produce spiritual experiences ranging from hallucinations – audible as well as visual, to visions and even out of body experiences.


The word bolide comes from the Greek βολίς (bolis) which can mean a missile or to flash. The IAU has no official definition of "bolide", and generally considers the term synonymous with a large meteor or  "fireball". The term generally applies to fireballs reaching magnitude -14 or brighter. Astronomers tend to use "bolide" to identify an exceptionally bright fireball, particularly one that explodes (sometimes called a detonating fireball).  If the magnitude of a bolide reaches -17 or brighter it is known as a superbolide.  The fact that they produce infrasound is well documented.


There is a bombing and gunnery range to the south of Fairbanks that is associated with nearby Eielson Air Force Base and the US Army base at Fort Wainwright. Explosions from bombs of up to 2000 pounds in size and the detonation of other ordnance south of Fairbanks are frequently detected by infrasound detection equipment.

Cathedral and church organs

Organ pipes, particularly the very low bass toned organs in Cathedrals are very effective at promoting spiritual experience. Although the organ may be playing a number of notes, there may be only one tone that produces the effect, but because organs maintain the tone for some time, this can be effective. All organ pipes produce highly complex notes and thus even a pipe that appears to be producing an audible sound may well be producing an inaudible infrasound frequency that will resonate an organ in your brain inducing an experience of some kind or other.  Some very big cathedral organs emit quite high intensity sound and achieve whole body resonance.

Drones, bagpipes and didgeridoos

A drone is the name of a musical instrument that only produces one note – one pitch sound. The sound is usually a humming – droning sound – hence the name. The sound is also capable of being sustained. The resonance of a drone pipe is extremely effective at inducing trance states and can include infrasound.  Didgeridoos are tuned to produce infrasound

Groves of trees [sacred groves!]

The geomagnetic forces of the earth produce telluric currents that are electric currents that travel in the earth . 
A grove of trees may have been sited or may exist on a spot where a telluric current is particularly active producing an electric current that travels through the tree .  The wood in the tree via its transducer effects produces a mechanical vibration – an oscillation which itself produces infrasound.  The alternative of course is that the trees’ movement itself produces infrasound.

Heavy machinery and vehicles

Numerous types of heavy machinery and equipment have produced hallucinations and visions. I found observations for tractors, air conditioning equipment, electric fans, airplanes, cars, manufacturing plant, plus many other types of equipment. The link in each case was that they produced infrasound as they vibrated

Storm waves and surf

Nonlinear ocean wave interactions in ocean storms produce pervasive infrasound vibrations around 0.2 Hz, known as microbaroms.  The evidence that severe waves produce infrasound seems to be fairly well established and proven.  Researchers from the USArray Earthscope, for example, have tracked down a series of infrasonic humming noises produced by waves crashing together and thence into the ocean floor, off the North-West coast of the USA. Potentially, sound from these collisions could travel to many parts of the globe.  Microbaroms are caused by standing sea waves in marine storms. The low-level natural-infrasound lies in the frequency range from 0.02 to 10 Hz and they have a period of about five seconds.


An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. Earthquakes are caused mostly by rupture of geological faults, but also by other events such as volcanic activity, landslides, mine blasts, fracking and nuclear tests. An earthquake's point of initial rupture is called its focus or hypocenter. The epicenter is the point at ground level directly above the hypocenter.  And earthquakes produce infrasound.


The infrasound given off by volcanoes is used to monitor their activity and also predict the effects of plume dispersal

Animal communication

Whales, elephants, hippopotamuses, rhinoceroses, giraffes, okapis, and alligators are known to use infrasound to communicate over distances—up to hundreds of miles in the case of whales. In particular, the Sumatran rhinoceros has been shown to produce sounds with frequencies as low as 3 Hz which have similarities with the song of the humpback whale. The roar of the tiger contains infrasound of 18 Hz and lower, and the purr of felines is reported to cover a range of 20 to 50 Hz


Helicopter blades produce low frequency sound [infrasound]. The University of Fairbanks in Alaska, for example, have been able to measure infrasound from a helicopter passing over the DOE array, it has also been recorded. The wave train and its spectrum showing the Doppler shift in the observed frequency of the signal as the helicopter approached and then receded from the array.  Hallucinations may be being caused by the infrasound, or the sun and the blades interacting [reverse REM].


Wind acting on high rise office building produces turbulence, turbulence can produce infrasound.  It is also possible for infrasound to be present within a building generated from electric fans, air conditioning systems, or simply via air flowing down long corridors unbroken by any furniture

PVDF Pipes

Polyvinylidene fluoride (PVDF): is a type of plastic which is used in all sorts of applications from pipes to insulation to building structures.  PVDF exhibits piezoelectricity properties such that when a current is applied through it, it produces mechanical vibrations and as a consequence sound – and more specifically infrasound.


According to the Infrasonics Program at NOAA, infrasonic arrays can be used to detect tornadoes on the high plains several minutes before they touch down.

Wind turbines

A wind turbine is a device that converts kinetic energy from the wind into mechanical energy. This mechanical energy can then be used to produce electricity and these are more correctly called  wind generators to distinguish them from wind turbines used to drive machinery [windmills or wind pumps].  And wind turbines produce infrasound.  If you work, live or are based near a wind turbine the infrasound is classified as high intensity, further away it is lower intensity. 


Waterfall Low-Frequency Vibrations and Infrasound: Implications for Avian Migration - Alfred J. Bedard; NOAA/ESRL/PSD/CIRES

This paper reviews past measurements, attempting to gain insight into the sound and vibration generation processes from weirs and waterfalls. Measurements made in the vicinity of Niagara Falls show that exceptional infrasonic pressure levels can occur in the regions of large waterfalls (>100Pa at a range of about 500 meters). Indications are that the dominant frequency from a waterfall is inversely proportional to the waterfall height and that the sound pressure level depends upon the hydrodynamic power of the waterfall.


We have provided a number of observations that describe other souces of infrasound, for example, bells and even the human voice.  We will add to these over time.

How it works

The effects - whether ill-health, visions, hallucinations, ecstasy and so on - are all produced via Resonance.  Resonance of the organs of the body.

Depending on the Intensity, duration and distance of the person from the source, different things can happen mentally as well as physically.  If the source is close, and the intensity high for example, the effects are suaully negative.  If the source is at some distance and the intensity very low, positive things can result.  The longer the duration, however, the more positive might turn into negative as the effects may accumulate.

This activity is a sub-activity of the entry for Stimulation via Resonance, and given its own entry because of the importance it seems to have in provoking bad health and spiritual experiences.

There is accumulating evidence that whales, dolphins and other sea creatures are dying from the effects of man made infrasound used in exploration for minerals, submarines and in deep sea fishing.  They beach themselves - a mass suicide.  Since infrasound can result in depression in humans, it could have the same effect in other mammals.


Related observations