from The American Heritage® Dictionary of the English Language, 4th Edition
- adj. Generating or using waves or vibrations with frequencies below that of audible sound.
from Wiktionary, Creative Commons Attribution/Share-Alike License
- adj. Having frequencies below the human audible range
- adj. Generating or employing such sound waves
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- adj. having frequencies below those of audible sound
Sorry, no etymologies found.
However, technological advances are making it possible to develop WMD based on qualitatively new principles, such as infrasonic (acoustic), radiological (enhanced-radiation), or particle-beam weapons.
Although we cannot hear these "infrasonic" waves - which have frequencies ranging from 0. 01-10 Hz - we know they exist from acoustic recordings around the globe.
Georgia Tech's center is testing highly sensitive "infrasonic" microphones that pick up sounds whose frequencies are too low to be detected by the human ear.
They may also use the infrasonic roar of distant ocean waves or wind in far-off mountains as acoustic landmarks.
Many animals, including birds, almost certainly hear infrasound; birds might even use the infrasonic rumblings of the ocean or the shifting plates of the earth to help navigate on their migrations.
Eruptive phenomena are monitored 24/7 and in all weather conditions with continuously transmitting seismic and infrasonic instruments designed to distinguish explosive, ash-producing eruptions from volcanic earthquakes and tremor without ash production.
What will hit us is noise, both the audible and the infrasonic, shadow-flicker, ice throw, and the deaths of birds and bats in our preserved fly way.
HSBC makes a good point that seismological evidence as well as infrasonic data would be of great value in determining the authenticity of the claim.
There was some debate about elephants congregating as if through magic, but then it was discovered that they were communicating through infrasonic sound waves.
Frequencies higher than audio are referred to as ultrasonic, while frequencies below audio are referred to as infrasonic.