1. Infrasound refers to sound waves that are lower in frequency than 20 Hz, which is below the normal range of human hearing. 2. Infrasound is used to study geological formations below the earth's surface and in medical applications, and can travel long distances with little loss of energy. 3. Some animals like whales, elephants, and rhinoceros use infrasound to communicate over distances of up to hundreds of miles.

1. NEVROZ GÖSTERİCİ

2. Infrasound is sound that is lower in frequency than 20 Hz (Hertz) or
cycles per second, the normal limit of human hearing. 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 levels it is
possible to feel infrasound vibrations in various parts of the body.

3. The study of such sound waves is sometimes referred to as infrasonics,
covering sounds beneath 20 Hz down to 0.001 Hz. This frequency
range is utilized for monitoring earthquakes, charting 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 cover long
distances and get around obstacles with little dissipation.

4. Infrasound was used by Allied forces in World War I to locate artillery. One
of the pioneers in infrasonic research was French scientist Vladimir
Gavreau, born in Russia as Vladimir Gavronsky. His interest in infrasonic
waves first came about in his lab during the 1960s, when he and his lab
assistants experienced pain in the ear drums and shaking lab equipment, but
no audible sound was picked up on his microphones. He concluded it was
infrasound and soon got to work preparing tests in the labs. One of his
experiments was an infrasonic whistle.

5. Infrasound sometimes results naturally from severe
weather, surf, lee
waves, avalanches, earthquakes, volcanoes, bolides, waterfalls, calvi
ng of icebergs, aurora, lightning and upper-atmospheric
lightning. Nonlinear ocean wave interactions in ocean storms
produce pervasive infrasound vibrations around 0.2 Hz, known
as microbaroms. Infrasound can also be generated by man-made
processes such as sonic booms and explosions (both chemical
and nuclear), by machinery such as diesel engines and older designs
of down tower wind turbines and by specially designed mechanical
transducers (industrial vibration tables) and large-
scale subwoofer loudspeakers. The Comprehensive Nuclear-Test-
Ban Treaty Organization uses infrasound as one of its monitoring
technologies (along with seismic, hydroacoustic, and atmospheric
radionuclide monitoring).

6. Whales, elephants, hippopotamuses, rhinoceros, giraffes, okapi, an
d alligators are known to use infrasound to communicate over
distances—up to hundreds of miles in the case of whales. It has
also been suggested that migrating birds use naturally generated
infrasound, from sources such as turbulent airflow
over mountain ranges, as a navigational aid. Elephants, in
particular, produce infrasound waves that travel through solid
ground and are sensed by other herds using their feet, although
they may be separated by hundreds of kilometres.

8. •Infrasound station. The stations detect and give the
azimuth of the nuclear explosions. The location is given by
the intersection of different azimuth

9. Animals have been known to perceive the infrasonic waves
going through the earth by natural disasters and can use these
as an early warning. A recent example of this is the 2004 Indian
Ocean earthquake and tsunami. Animals were reported to flee
the area long before the actual tsunami hit the shores of Asia.It
is not known for sure if this is the exact reason, as some have
suggested that it was the influence of electromagnetic
waves, and not of infrasonic waves, that prompted these
animals to flee.

10. An elephant generates and probably
detects infrasound.
A cassowary might pick up ultrasonic
signals with its casque, a mysterious
structure on top of its head. No one is yet
sure what this structure is for.

11. 20 Hz is considered the normal low frequency limit of human hearing.
When pure sine waves are reproduced under ideal conditions and at very
high volume, a human listener will be able to identify tones as low as
12 Hz. Below 10 Hz it is possible to perceive the single cycles of the
sound, along with a sensation of pressure at the eardrums.
The dynamic range of the auditory system decreases with decreasing
frequency. This compression can be seen in the equal-loudness-level
contours, and it implies that a slight increase in level can change the
perceived loudness from barely audible to loud. Combined with the
natural spread in thresholds within a population, it may have the effect
that a very low frequency sound which is inaudible to some people may
be loud to others.

12. Infrasound has been known to cause feelings of awe or fear in
humans.Since it is not consciously perceived, it can make
people feel vaguely that supernatural events are taking place.
Some film soundtracks make use of infrasound to produce
unease or disorientation in the audience. Irréversible is one
such movie.
The infrasound and low-frequency noise produced by
some wind turbines is believed to cause certain breathing and
digestive problems in humans and other animals in close
proximity to the turbines.

13. An Infrasonic