The Taos Hum
In the early 1990s, residents of Taos, New Mexico began reporting a persistent low frequency sound, somewhere between a diesel engine idling and a distant rumble, that they could hear inside their homes but not explain. The sound was present day and night and for some listeners caused headaches, nosebleeds and nausea. A team from multiple American universities and the Los Alamos National Laboratory investigated in 1997. They found nothing.
First reports
Early 1990s, Taos, New Mexico.
Hearers
Approximately 2 percent of the local population reports the sound.
Frequency
Estimated between 30 and 80 Hz, below the threshold of most microphones.
Investigation
1997 University of New Mexico and Los Alamos team. No source identified.
Global versions
Similar hums reported in Bristol, Windsor, Largs and the Kokomo area.
What investigators ruled out or confirmed
Industrial activity in the Taos area tested and cleared
Military installations in the region investigated and denied involvement
Geological sources including gas seepage considered
A physical source identified for the Taos Hum specifically
A medical cause confirmed for universal sufferers
The hum recorded by any instrument at matching frequency
"We found nothing. The hearers are credible. The sound is real to them. We cannot find it.
"Taos Hum investigator
One current theory proposes that some people can perceive infrasound through cochlear amplification, hearing vibrations that standard equipment cannot measure.
The Bristol Hum was tentatively linked to offshore ship traffic in 2016. The Taos Hum has no equivalent partial explanation to date.