Geologists are scratching their heads over the reasons mysterious hum

February 23, 2008. Researchers have found another permanent low-frequency signal propagating in the Earth. Its nature is unknown.

For nearly ten years, is known for a very weak constant vertical oscillations of the earth's surface, caused probably continuous impact of seismic waves on the ocean floor. Now, a team of scientists from Germany found a second note of this buzz, this time the horizontal, but to explain its origin, they could not.

For 11 years, Dieter Kurrle and Rudolf Widmer-Shnidrih, the staff of the University of Stuttgart, studied data from seismometers four isolated points in Germany, Japan and China. Was a non-trivial task, as it was necessary to take into account changes in atmospheric pressure on the planet's surface in the area of measurement.

Scientists have proven the existence of a horizontal signal in the data of all four stations. Signal represents motion within 1 micrometer in any direction approximately every three minutes. The horizontal direction of these movements clearly separates them from the vertical oscillations of the Earth.

Some natural phenomena (earthquakes, volcanic eruptions, severe storms) can enhance this continuous signal, but its source has not been determined. Judging by the frequency of the signal strength of any "twisting" the surface of the Earth's crust in some way. When the exposure ends, bark back to the previous state because of its elasticity. And the process is repeated curling and straightening.

Widmer-Shnidrih suggests that perhaps these fluctuations are caused by eddies in the atmosphere in areas of low pressure. At the same time, he acknowledges that this theory — shooting into space, because it can not be confirmed.

Other scientists have turned their attention to the sky, hoping to find an explanation. At the annual meeting of the American Geological Union, David Thompson, of Queen's University, Canada, and Frank Vernon Institute of Oceanography in California suggested that the buzz is synchronized with changes in the magnetic field of the Sun. However, Widmer-Shnidrih was skeptical:

— What is the basis of correlation? To date, there is no single theory that can be predicted or explained the results of observations.

Translation: Vitaly Semkin
Source: NewScientist.com

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