“The roar of the Earth” scared scientists

French, German and British geophysicists for almost 20 years can not explain the nature of the hum of the Earth – acoustic anomalies, manifested in the vibrations of the ocean floor.

Scientists recorded oscillations with a frequency of 2.9-4.5 millihertz at two points of the Indian Ocean at a depth of 4,540 and 4,260 meters. Perturbations were observed even with minimal seismic activity and were ten thousand times lower than the sensitivity threshold of the human ear.

For the first time the roar of the Earth was registered in 1998. The nature of the phenomenon to geophysicists is still incomprehensible, but they have several hypotheses explaining the phenomenon. Among them – an acoustic resonance between the atmosphere and the earth’s crust, or the interaction of the earth’s crust with ocean waves.