Seldom does anyone think about how many different sounds exist in nature. Few people know that the sound itself does not exist as such, and what a person hears is just converted waves of a certain frequency. The hearing aid that people have is able to convert some of these waves into the sounds we are used to. However, this is only a small fraction of all those frequencies that surround everyone. Some of them, which cannot be heard without special instruments, can cause significant harm to the human body.
Concept
Infrasound is sound vibrations with a frequency of less than 16 Hz. The existing world is full of sounds, and they all have a different range. The human hearing aid is designed to receive sounds with a frequency of at least 16 vibrations per second, but not more than 18-20. Such fluctuations are measured in hertz (Hz). However, such sound vibrations can be either above or below the specified range. Such frequencies, inaudible to humans, are the so-called areas in which ultrasound and infrasound exist. These oscillatory processes are absolutely inaudible to humans, however, at the same time, theycan affect various processes, including the human body.
The human brain is designed in such a way that it is able to perceive only a small part of those phenomena occurring in the sound environment that can reach the inner ear, its peripheral receptor devices. At the same time, the perception of such acoustic waves will be determined by several factors, including the focus of attention, the resolution of receptors, and the speed of transmission along the nerve pathways.
Sound
As mentioned, the frequency range of infrasound is below the range of human perception of sounds. The essence of infrasound is no different from other sounds. In general, sound is called elastic waves that move in a certain medium and, with their such movements, create mechanical vibrations. In other words, sound can be called the movement of air molecules, which occurs as a result of the vibration of a physical body. As an example, one can cite vibrations originating from stringed instruments. In order for sound to propagate, there must be air. It is well known that silence always reigns in a vacuum. This is because as a result of physical action, reciprocating air movements occur, which, in turn, cause waves of compression and rarefaction.
Features of infrasound
Infrasound is a low-frequency wave process, and although its physical essence is the same as that of another sound, it has several features. So,low-frequency waves have a large penetrating power. This is due to the fact that they are characterized by low absorption. Infrasound propagated in the depths of the ocean or in the air space near the earth, having a frequency of ten to twenty hertz, as a rule, attenuates after traveling a thousand kilometers by only a few decibels. The same slight scattering of infrasonic waves occurs in the natural environment. This is due to the huge wavelength. So, the last value, if the frequency of infrasound is 3.5 Hz, will be about 100 meters. The only thing that can have a significant impact on the dispersion of these acoustic waves is large objects (high-rise buildings and structures, mountains, rocks, etc.). These two factors - low absorption and low scattering - contribute to the movement of infrasound over long distances.
For example, sounds such as volcanic eruptions or nuclear explosions can go around the surface of the globe several times, and waves resulting from some kind of seismic vibrations can overcome the entire thickness of the planet. As a result of these reasons, infrasound, whose impact on a person is very negative, is practically impossible to isolate, and all materials used for sound insulation and sound absorption lose their properties at low frequencies.
Infrasound and processes occurring in the human body
As already noted, the length of the low-frequency wave is quite large, so its penetration into the human body, into its tissues can also be expressed to a large extent. To put itfiguratively, a person, although he does not hear infrasound with his ears, he hears it with his whole body. Infrasound can affect a person in different ways, it can coincide with many processes occurring in the human body. After all, many organs also create certain sounds. For example, the heart during contraction creates infrasound with a frequency of 1-2 Hz, the brain during sleep - from 0.5 to 3.5 Hz, and during its active work - from 14 to 35 Hz. Naturally, if the external infrasonic vibrations somehow coincide with the vibrations occurring in the human body, then the latter will only increase. And this amplification can eventually lead to damage to the organ, its breakdown or even rupture.
Sources in nature. Sea waves
Nature is literally penetrated by infrasound. This is caused by many phenomena, including sudden changes in pressure, and volcanic eruptions, and seismic activity, and hurricanes, as well as many other factors. Numerous studies conducted on people who fell into the zone of action of low-frequency waves gave scientists reason to believe that infrasound is dangerous for a person, for his he alth. These waves provoke a loss of sensitivity of the organs designed to regulate the balance of the body. In turn, this loss causes earaches, brain damage, and spinal pain. Some scientists and psychologists believe that infrasound is the main and most serious cause of psychological disorders.
He always exists,even when people think the atmosphere is quiet. Sources of infrasound are various and diverse. The impact of sea waves on the shore, firstly, causes small seismic vibrations in the bowels, and secondly, contributes to changes in air pressure. With the help of special barometers, it is possible to catch such fluctuations. Powerful gusts of wind, combined with sea waves, are the source of powerful low-frequency waves. They move at the speed of sound, and as they spread through the waves of the sea, they get even stronger.
Forecasters
Such infrasounds are harbingers of a storm or hurricane. It is no secret that animals have a unique ability to predict such natural phenomena. For example, jellyfish, which even before the start of the storm move away from the coast. This ability to predict, according to some scientists, is also available to individuals. Since ancient times, people have been known who, looking at a calm and serene sea, could announce an imminent storm. When studying this fact, it turned out that such people feel pain in the ears, which are caused by infrasonic waves. In addition, low-frequency waves that appear as a result of a storm affect a person’s behavior and his psyche. This can be expressed both in malaise, memory impairment, and in an increase in the number of suicidal attempts.
Earthquakes and volcanic eruptions
Infrasound in nature can also occur as a result of an earthquake. With its help, for example, the Japanese predict the imminent appearance of a tsunami that occurs inthe result of underwater seismic activity. Boris Ostrovsky, a researcher in this field, claims that over fifty thousand underwater earthquakes occur in the World Ocean every year, and each of them creates infrasound. This phenomenon and its mechanism are characterized as follows. It is well known that seismic activity occurs as a result of the accumulation of energy in the earth's crust. Eventually this energy is released and the bark ruptures. It is these forces that create low-frequency vibrations. In this case, the intensity of infrasound is directly proportional to the intensity of energy in the earth's crust. During an underwater earthquake, transverse low-frequency waves move through the water column and further, reaching the ionosphere. A vessel that has fallen into the area of radiation of such waves will be affected by infrasound. If such a ship stays in the specified area for a long time, then it can become a so-called resonator. That is, in other words, a subsequent source of low-frequency waves. This ship will transmit, like a speaker, infrasound. The influence of this factor on a person is sometimes the cause of an inexplicable fear in people on the ship, often turning into horror. Some researchers argue that this is the key to the discovery of ships on the high seas without a crew. People who find themselves in such a situation are looking for a way out, escape from the ship, just to hide from this inaudible sound that drove them crazy.
The greater the intensity of the low-frequency oscillations, the more panic can seize the people on the resonator ship. Thisinexplicable horror will be interpreted by human consciousness, its cause will be searched for. Perhaps this is what influenced the emergence of such common myths as calling sirens. If we study the ancient myths in more detail, we can assume that the rowers, laying their ears with soundproof devices, as well as other members of the ship's crew, who tied themselves to the masts, tried to protect themselves in this way. It was a kind of protection against infrasound.
There are many cases in history when a ship was found with the dead bodies of the crew. And here the theory of infrasound is applicable. As mentioned above, if it coincided with the frequencies emitted by the internal organs of a person, then, as a rule, it was amplified many times over. This amplified infrasound was quite capable of tearing apart internal organs, hence causing sudden death. Killer infrasound was most likely responsible for several deaths that occurred in 1957 in Mongolia. Then, on December 4, there was a powerful earthquake. According to eyewitnesses, some people, including shepherds grazing cattle, literally fell dead even before the Gobi-Altai earthquake.
Volcanic eruptions are another source of infrasound. The frequency of the waves of the infrasound that appears in this case is about 0.1 Hz.
According to some statements, all kinds of ailments that appear in people during bad weather are caused by nothing more than infrasound.
Production sources
Unlike nature, which is not so commoncomplicates a person's life with its low-frequency sounds, infrasound, which appears as a result of human activity, has an increasingly negative impact on people. These low-frequency waves appear along with the same processes that produce human-audible sounds. One of these are gun shots, explosions, sound radiation emanating from jet engines.
Factory compressors and fans, diesel installations, all kinds of slow-running units, urban transport - these are all sources of infrasound. The most powerful low-frequency waves cause the meeting of two trains at speed, as well as the passage of the train in the tunnel.
The further humanity develops, the more powerful and voluminous machines and mechanisms are developed and produced. Accordingly, this is accompanied by an increase in the generated infrasonic waves. Of particular danger is infrasound in production due to the fact that it has not been fully studied in this area.
Infrasound and man
The negative impact of infrasound on humans is confirmed by many studies. Some scientists believe that it has an undoubted negative effect not only on the body, but also on the psyche of people. Thus, the experiments that astronauts are subjected to allow us to say that the subjects under low-frequency waves solve simple mathematical problems more slowly.
Scientists in the field of medicine have determined that at a frequency of 4-8 Hz, a dangerous resonance of the abdominal cavity is detected. Duringpulling this area with belts, an increase in the frequency of sounds was observed, however, the effect of infrasound on the body did not stop.
One of the largest resonating objects in the human body is the heart and lungs. In cases where their frequencies coincide with external low-frequency waves, they are subject to the strongest vibrations, which can ultimately lead to cardiac arrest and damage to the lungs.
Many works of scientists are devoted to the effects that infrasound has on the brain. Low-frequency waves can affect a person in different ways. Studies have shown that there is some similarity between the effects of alcohol and the effects of infrasound. So, in both cases, both of these factors actively inhibit mental work.
Low-frequency waves also have a negative impact on the circulatory system. Experiments have been carried out by researchers in this area. As a result, the subjects who were treated with infrasound experienced a sharp drop in blood pressure, arrhythmia, respiratory failure, fatigue and other disturbances in the normal functioning of the body.
Everyone has met with a situation when, after a long and tiring trip by car or swimming in the sea, a bad condition sets in, in which a gag reflex appears. Usually people in such cases say that they are seasick. However, this is the direct effect of infrasound, which manifests itself in the action on the vestibular apparatus. Interestingly, with the help of infrasound, in ancient Egypt, priests torturedtheir prisoners. They tied them up and by means of a mirror and sun glare directed into the eyes of the victim, they achieved the appearance of convulsions in the latter. It was the influence of infrasound. The will of such captives was suppressed, and they were forced to answer questions asked of them.
Conclusion
And although ultrasound and infrasound have not yet been fully studied, and there are many gaps in their understanding, the latter has been associated with some natural disasters since ancient times. Their subconscious allowed them to avoid many troubles, and infrasound itself was perceived by a person as a harbinger of something bad. Over time, this feeling in humanity gradually atrophied. However, even now, suddenly, out of nowhere, an inexplicable fear that has come from can warn a person against something bad, forcing him to run away and hide from the overtaking horror.
