Question

Characteristics of infrasonic waves

Answer 1

Infrasonics, vibrational or stress waves in elastic media, having a frequency below those of sound waves that can be detected by the human ear—i.e., below 20 hertz. The range of frequencies extends down to geologic vibrations that complete one cycle in 100 seconds or longer.

Answer 2

The term "infrasonic" applied to sound refers to sound waves below the frequencies of audible sound, and nominally includes anything under 20 Hz.

Sources of infrasound in nature include volcanoes, avalanches, earthquakes and meteorites.

Infrasound also may be used for long-distance communication, especially well documented in baleen whales (see Whale vocalization), and African elephants.