The upper mantle of the Earth

According to different sciences, the model of a multi-storey device is known Earth: bark, lying from the surface to 15-70 km, then the mantle, which is below 2900 km is replaced by the core of the planet. The density mantle is divided into three parts: the upper, or asthenosphere (50-400 km), medium, or transitional (400-1000 km), lower (1000-2900 km).

It turned out that the upper mantle of the Earth is more complicated than even the most daring researchers have imagined

Is it possible to trust such a static and one-dimensional Earth model? In any case, to doubt it only on the grounds that it can not be checked visually, there is no sense. But recently, the hypothesis of the motion of plates of the earth's crust has become popular, which are driven by giant streams of plastic substance of the mantle, peculiar stone whirlwinds. Mantle cycles give rise to the heating of its substance by heat flows from the core of the planet: hotter light masses emerge, and heavier colds sink. In direct dependence on the direction of neighboring vortices, either the approach of the plates of the earth's crust occurs, their collision, the tightening of one under the other, the expansion, or the plates diverge, forming deep depressions and depressions in the earth's crust. In short, the bark of our planet floats on the stormy waves of the upper mantle of the Earth. And this global drift is associated with tremendous geological processes: earthquakes, the birth of volcanoes and the formation of mountains. The centers of most of them are located precisely in the upper mantle of the Earth.

But then a strange circumstance was discovered. Some scientists argued that the upper mantle of the Earth has layers of reduced density, others completely denied the existence of the decompressed zones in the upper mantle. Finally, there were some experts who argued that the upper mantle of the Earth has areas not of reduced but of increased density!

It turned out that the upper mantle of the Earth is more complicated than even the most daring researchers have imagined. It is heterogeneous, in density, and possibly in composition. It, in complete contrast to the earth's crust, under the oceans is usually much more powerful than under the continents, and in the zones of transition from the continent to the ocean, the upper mantle of the Earth is arranged most difficultly. But what happens in it and according to what laws does its substance move? Not having a spatial picture, it is impossible to understand the behavior of the upper mantle of the Earth.

Therefore, the problem arose of creating a three-dimensional model of the upper mantle. To do this, began to build horizontal profiles of the earth. The square of the earth's surface an area of several kilometers was blocked by a dense network of seismographs. Subsoil shone through a series of synchronized explosions. Seismographs recorded signals reflected from various deep layers. The recording of each device passed through an interference filter, which passed only the reflection data from the plane at a given depth. These filtered seismograph data actually provided information about the distribution of the inhomogeneity in the plane at the required depth. Having processed the data of individual seismographs, computer synthesized a complete picture of the distribution of inhomogeneities in the given plane - its photo. But the mantle itself has not yet been reached. In the explosion, only a small fraction of the energy of the flare emits into the interior, and the large simply goes to the useless shaking of the air.

Now scientists are conducting intensive work on numerical modeling and application of the principles of optical holography. In contrast to optics, which uses two coherent light beams - objective and reference, seismograms can only use a subject beam, and the reference can be artificially reproduced in the course of data processing on a computer. And then, before the eyes of scientists, highlighted by the ray laser, programmed by a computer, there will immediately appear a voluminous picture of the salt dome, the deposits of oil, unknown until the upper mantle of the Earth!

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