From the depths of the ocean recorded a strange sound

Acoustic anomalies caused by the fluctuations of the ocean floor.

Geophysics using data from seismographs recorded the acoustic anomalies caused by free oscillations of the ocean floor. About his discovery, the researchers reported in the journal Geophysical Research Letters.

The audibility of oscillations was 10 thousand times below the minimum threshold of perception of the human ear. The first time a similar phenomenon was documented in 1998, but still remains unclear the cause of its occurrence. The specialists underline that the “rumble” occurs even at zero seismic activity.

New data were obtained by a team of scientists from France and Germany, led by Martha Dean of the Paris Institute of physics of the Earth. Geophysicists have studied the fluctuations of the bottom of the Indian ocean at two points on the depth and 4540 4260 meters and recorded a constant sound wave frequency from 2.9 to 4.5 millihertz.

According to the researchers, “hum” can arise either due to the acoustic resonance between the atmosphere and the earth’s crust, either due to the interaction of solid surfaces with ocean waves.

Earlier, the international group of geologists have found that solid metal core inside the Earth was formed 1-1. 5 billion years ago. Also, scientists were able to determine the growth rate of the earth’s core: the year the radius increases by approximately 1 mm.

paradox