Since 1991, people in the Taos, New Mexico area have reported hearing an annoying, low-frequency hum, the cause of which has yet to be identified (Ufologist, Vol.2, No.3, 1992). Recent reports suggest that the Hum is not merely localized to Taos, but may be a nationwide, or perhaps even worldwide, problem.
Some investigators suspect the Hum may be caused by the Extremely Low Frequency (ELF) submarine communications system. The frequency of the Hum seems to be between 33 and 80 Hertz, while the USA's ELF system is believed to operate at frequencies around 76 Hertz.
The US Navy first conducted experiments on ELF wave propagation and environmental effects in 1969, using two antennas each 14 miles long located at Clam Lake, Wisconsin. Experiments with this facility continued until 1976, when when actual ELF communications with submarines were demonstrated. Shortly thereafter, the Navy made plans for an operational ELF communications system using buried antennas so as to be hardened against nuclear attack. This system, code-named Sanguine, was cancelled after studies determined that the system would be vulnerable to nuclear attack.
Despite the cancellation of Sanguine, the Navy began development of an above-ground ELF system using antennas 28 miles long, also located at Clam Lake. This system, code-named Seafarer, was opposed by environmental groups and residents of the area concerned about possible adverse health effects of ELF radiation.
President Carter cancelled Seafarer in 1978, but the program was revived by President Reagan in 1981. The revived ELF system employs antennas 56 miles long on the upper penninsula of Michigan, in addition to the 28 mile long antennas in Wisconsin. Each antenna is powered with a 660 kilowatt transmitter. This system became operational in 1987.
The ELF communications system used by the United States uses two frequency bands, 40 to 50 Hertz, and 70 to 80 Hertz. The principle operating frequency is thought to be 76 Hertz, which seems to be one of the frequencies associated with the Taos Hum.
The Commonwealth of Independent States is believed to be maintaining the ELF communications system used by the former Soviet Union. The Soviet system was probably in operation as early as the 1970s, and used two transmitters at Riga and Gomel. The Soviet system broadcast at 8 Hertz, and perhaps other frequencies as well.
In addition to the USA and the CIS, there is a British ELF site in the Glen Cally Forest in Scotland, and a French system sited at Roshay. Both the British and French systems were due to be operational prior to 1990.
As mentioned above, the ELF transmitting facilities in Wisconsin were opposed by residents and environmental groups. A number of studies of possible health and environmental effects were supported by the Navy, and there was an exhaustive review of ELF-related research by the National Academy of Sciences in 1976.
The National Academy of Sciences review looked at studies of the effects of ELF on genetics, reproduction, cell growth and division, circadian rhythms, electro-sensitive fish, insect behavior, bird migration, effects on plants, soil organisms, and effects on neurophysiology and behavior of mammals.
Apparently, though, nobody thought to study the simpler question of whether anyone could HEAR a hum from the ELF fields.
Despite a few studies that suggested that ELF fields do cause some measurable biological effects, the NAS review panel concluded that the ELF communications system was unlikely to cause any health or environmental problems. Curiously, the studies on mammalian neurophysiology that were reviewed by the NAS panel did contain some evidence that brain nerve cells could be effected by ELF fields. In fact, it was assumed that ELF fields could stimulate electrical activity in the brain, but it was also assumed that these effects shouldn't be noticable because they would be far smaller than the normal electrical activity in the brain. Despite these assumptions, there was, in fact, some evidence that changes in brain nerve cell response could occur even from very weak electrical influences, much weaker than the normal nerve impulses.
The NAS panel concluded based on extrapolation rather than direct evidence, that neurophysical and neurochemical effects would only occur for electric and magnetic field strengths much higher than those expected to be induced by the ELF system.
The National Academy of Sciences review seemed, at least at the time, nearly 20 years ago, to give the ELF communications system a clean bill of health. It's not known whether any follow-up studies have been done since the ELF communications system became operational.
Since the frequency used by the ELF communications system, around 75 Hertz, is within the range reported for the Taos Hum, the ELF system seems a natural suspect as the cause of the hum. However, it is not known why the Hum was not detected until 1991 if the ELF communications system went into operation in 1987. If there was a direct cause and effect relationship, one would expect that the Hum would have been noticed several years earlier. Furthermore, the Hum is reported to have frequency components ranging from 17 to 32 Hertz and higher, yet these are not frequencies in use for the ELF communications system. Even if the 76 Hertz ELF system were contributing to the Hum, the other frequency components would need to be explained. Perhaps the 76 Hertz frequency match is coincidental. Obviously, further investigation is needed to identify the cause of the Taos Hum.