(1) These infrasonic sounds are capable of traveling long distances, and most occur in the early morning or evening hours, when ground air is cool enough to carry the frequency without interference.(2) At the infrasonic level, according to Stephen Handel, ‘sound no longer has a continuous tonal quality; we do hear sounds below 20 Hz, but they resemble a series of independent thumps’.(3) The infrasonic range is roughly between 1 and 20 Hz.(4) Rhinoceroses produce infrasonic vocalizations, though their vocal repertoire is still largely undocumented.(5) Using calls that have infrasonic fundamental frequencies, female elephants are able to communicate with large numbers of specific individuals over long distances.(6) Powerful infrasonic calls enable them to send messages and warnings, sometimes over long distances.(7) Preliminary findings with electrostatic fields, ionizing radiation, infrasonic waves, and meteorological factors are also examined to consider their effects on the brain in relation to apparitional experiences.(8) When the rate of vibration is below the range of human hearing, the sound is termed infrasonic ; when it is above that range, it is called ultrasonic.(9) Seismologists and volcanologists use both seismic and infrasonic signals to monitor volcanic activity.(10) He says he once invited people to spend a few minutes in a container he was pumping with infrasonic sound.(11) The routine up-and-down movements of the waves act as a giant loudspeaker, pushing the air at infrasonic frequencies.(12) The paralysing effect of a tiger's roar is said by some to come from its infrasonic content (around 18Hz, the resonant frequency of the human eyeball, alarmingly).(13) Rain has a very low infrasonic signal and the elephants hear it over great distances,’ he said.(14) One psychologist thinks that the odd sensations that people attribute to ghosts may be caused by infrasonic vibrations.(15) In addition to meteors, infrasonic energy is generated by chemical explosions, supersonic aircraft, tornadoes, landslides, earthquakes, and volcanoes.(16) Singing whales appear to slalom from one geographic feature to the next using the echoes of their intense, infrasonic voices to navigate.
