infrasound
Below hearing's threshold
Infrasound is sound at frequencies below the range of human hearing—typically under 20 hertz.
Elephants and whales communicate using infrasound, which travels farther than audible frequencies.
Earthquakes, volcanoes, and large machinery produce infrasound.
Some researchers have linked infrasound exposure to feelings of unease or dread, offering a possible explanation for haunted locations.
Rate of recurrence
- hertzFrequency measurement unit
- wavelengthSpatial repetition interval
- amplitudeMaximum oscillation displacement
- waveformGraphed oscillation pattern
oscillation · resonance · acoustic · low-frequency · soundwave · pressure · decibel · propagation
Exchanging ideas or information
- rumbleLow rolling sound
- herdGrazing animals together
- seismicRelating to ground tremors
- vocalizationProducing sounds with voice
long-distance · matriarch · detection · savanna · warning
Study of ground tremors
- earthquakeSeismic ground movement
- volcanoEarth's fiery vent
- tsunamiSeismic sea surge
- tectonicsStudy of crustal deformation
mantle · fault-lines · eruption · magma · tremor · microseism · geodynamics · seismograph
Exchanging ideas or information
- cetaceansAquatic mammals, fully marine
- humpbackBaleen whale species
- vocalizationsSounds produced by voice
- underwaterBelow the surface
pods · migration · long-distance · song · calling · mating · hydrophone
Violent atmospheric disturbances
- thunderStorm's acoustic aftermath
- tornadoViolent rotating windstorm
- hurricaneViolent tropical windstorm
- typhoonWestern Pacific hurricane
atmospheric · wind · turbulence · avalanche · meteor · lightning · detection · forecasting
Ongoing observation of something
- detectionAct of finding something
- sensorsDevices that detect input
- covertIntentionally concealed
- militaryArmed forces collectively
explosion · reconnaissance · early-warning · tracking · intelligence · clandestine · verification · array
Point of beginning
- perceptionMental interpretation of stimuli
- hearingPerceiving sound waves
- humanHomo sapiens individual
- sensationPerceived stimulus or phenomenon
psychoacoustics · auditory · subliminal · imperceptible · felt · undetectable · physiological · discomfort
frequency
Rate of recurrence
- hertzFrequency measurement unit
- wavelengthSpatial repetition interval
- amplitudeMaximum oscillation displacement
waveform · oscillation · resonance · acoustic · low-frequency · soundwave · pressure · decibel · propagation · longitudinal
communication
Exchanging ideas or information
vocalization · long-distance · matriarch · detection · savanna · warning
seismology
Study of ground tremors
- earthquakeSeismic ground movement
- volcanoEarth's fiery vent
- tsunamiSeismic sea surge
tectonics · mantle · fault-lines · eruption · magma · tremor · microseism · geodynamics · seismograph · precursor
communication
Exchanging ideas or information
- cetaceansAquatic mammals, fully marine
- humpbackBaleen whale species
- vocalizationsSounds produced by voice
underwater · pods · migration · long-distance · song · calling · mating · hydrophone
storms
Violent atmospheric disturbances
- thunderStorm's acoustic aftermath
- tornadoViolent rotating windstorm
- hurricaneViolent tropical windstorm
typhoon · atmospheric · wind · turbulence · avalanche · meteor · lightning · detection · forecasting · oceanic
monitoring
Ongoing observation of something
military · explosion · reconnaissance · early-warning · tracking · intelligence · clandestine · verification · array · station
threshold
Point of beginning
- perceptionMental interpretation of stimuli
- hearingPerceiving sound waves
- humanHomo sapiens individual
sensation · psychoacoustics · auditory · subliminal · imperceptible · felt · undetectable · physiological · discomfort · nausea
- soundechoes, acoustics, vibrations, audio, volume
- animal signalsbody language, bird songs, tail wagging, mating calls, whale song
- sound & wavessonic booms, thunder, sonar, echolocation, bass
- acousticssoundwave, vibration, wavelength, resonance, amplitude
- limits of hearingauditory threshold, frequency range, hearing range, pitch range, volume limits
- sound phenomenaecho, echoes, reverb, resonance, reverberation
infrasoundultrasound
Inaudible high-frequency waves
ultrasonic waves · high-frequency sound · high-pitched sound · treble · high notes