Movement of the Earth's Crust: Scheme and Types

At first glance, the soil under the feet seems completely immobile, but in fact it is not. The earth has a mobile structure that makes movements of a different nature. The movement of the earth's crust, volcanism in most cases can carry a colossal destructive force, but there are other movements too slow and invisible to the unaided human eye.

The concept of the motion of the earth's crust

The Earth's crust consists of several large tectonic plates, each of which makes movements under the influence of the internal processes of the Earth. The movement of the earth's crust is a very slow, we can say, century-old phenomenon, which is not felt by the human senses, and yet this process plays a huge role in our life. Notable manifestations of the movement of tectonic layers are the formation of mountain chains, accompanied by earthquakes.

The causes of tectonic movements

The solid constituent of our planet - the lithosphere - consists of three layers: the core (the deepest), the mantle (intermediate layer), and the earth's crust (the surface part). In the core and the mantle, too high a temperature causes the solid matter to change to a fluid state with the formation of gases and a rise in pressure. Since the mantle is confined to the earth's crust, and the mantle substance can not increase in volume, the result is the effect of the steam boiler, when the processes occurring in the bowels of the earth activate the movement of the earth's crust. In this case, the movement of tectonic plates is stronger in areas with the greatest temperature and pressure of the mantle on the upper layers of the lithosphere.

Study history

A possible shift in the layers of the earth's surface was guessed long before our era. So, history knows the first assumptions of the ancient Greek scientist - geographer Strabo. He put forward the hypothesis that some parts of the Earth periodically rise and fall. Later, the Russian encyclopedist Lomonosov wrote that tectonic movements of the earth's crust are inconspicuous earthquakes for humans. Guessing about the movement of the earth's surface and the inhabitants of medieval Scandinavia, who noticed that their villages, once founded in the coastal zone, through the centuries were away from the sea coast.

Nevertheless, the movement of the earth's crust, volcanism began to be purposefully and scrupulously studied during the active development of scientific and technological progress that took place in the XIX century. Studies were conducted by our Russian geologists (Belousov, Kosygin, Tetiaev, etc.) and by foreign scientists (A. Wegener, J. Wilson, Gilbert).

Classification of the types of motion of the earth's crust

The pattern of movement of the earth's crust is formed of two types:

• Horizontal.
• Vertical movements of tectonic plates.

Both these types of tectonics are self-sufficient, independent of each other and can occur simultaneously. Both the first and the second play a fundamental role in shaping the relief of our planet. In addition, the types of movement of the earth's crust are the primary object of the study of geologists, since they:

• They are the direct cause of the creation and transformation of the modern relief, as well as the transgression and regression of some sections of marine areas.
• Destroy primary relief structures of folded, inclined and discontinuous type, creating new ones in their place.
• They ensure the exchange of substances between the mantle and the earth's crust, and also ensure the release of magmatic matter through channels to the surface.

Horizontal tectonic movements of the earth's crust

As it was said above, the surface of our planet consists of tectonic plates on which continents and oceans are placed. Moreover, many geologists of our time believe that the formation of the current image of the continents was due to the horizontal displacement of these most huge strata of the earth's crust. When the tectonic plate is displaced, the continent that is on it is displaced along with it. Thus, horizontal and at the same time very slow movements of the earth's crust led to the fact that the geographical map for many millions of years was transformed, the same continents were moving away from each other.

The most accurately studied tectonics of the last three centuries. The movement of the earth's crust at the present stage is investigated with the help of high-precision equipment, thanks to which it was possible to find out that the horizontal tectonic displacements of the earth's surface are exclusively unidirectional in nature and overcome only a few cm per year.

When displaced, tectonic plates converge in some places, but in some areas they diverge. In the collision zones of plates, mountains are formed, and in the zones of plate divergence, cracks (faults). A striking example of the divergence of lithospheric plates, observed at the present time, are the so-called Great African faults. They differ not only in the longest cracks in the earth's crust (more than 6,000 km), but also in extreme activity. The breakdown of the African continent is so fast that it is likely that not in such a distant future the eastern part of the continent will separate and form a new ocean.

Vertical movement of the earth's crust

Vertical movements of the lithosphere, also called radial movements, in contrast to horizontal ones, have a double directionality, that is, the land can rise and after a while fall. The consequence of vertical movement of the lithosphere is also a rise (transgression) and a descent (regression) of sea level. The age-old movements of the earth's crust up and down, which took place centuries ago, can be traced to the traces left, namely: the Naples temple, built as far back as the 4th century AD, is currently at an altitude of more than 5 m above sea level, however Its columns are strewn with shells of mollusks. This is clear evidence that the temple has been under water for a long time, which means that this section of the soil systematically moved in the vertical direction, then along the ascending axis, then downward. This cycle of movements is known as the vibrational modes of motion of the earth's crust.

Regression of the sea leads to the fact that once the seabed becomes land and plains are formed, among which the North and West Siberian plains, the Amazon, Turan, and others can be named. Currently, in Europe there are land uplifts (Scandinavian Peninsula, Iceland, Ukraine, Sweden) and subsidence (Holland, south of England, northern Italy).

Earthquakes and volcanism as a consequence of the movement of the lithosphere

The horizontal movement of the earth's crust leads to a collision or fracture of tectonic plates, which is manifested by earthquakes of various strengths, which is measured on the Richter scale. Seismic waves up to 3 points on this scale are not perceptible by man, fluctuations in soil with magnitude from 6 to 9 are already capable of leading to considerable destruction and death of people.

Due to the horizontal and vertical movement of the lithosphere, channels are formed at the boundaries of tectonic plates, through which the mantle substance under pressure is ejected onto the earth's surface. This process is called volcanism, we can observe it in the form of volcanoes, geysers and warm springs. On Earth, there are many volcanoes, some of which are still active. They can be both on land and under water. Together with the magmatic people, they spew hundreds of tons of smoke, gas and ash into the atmosphere. Underwater volcanoes are the main cause of the tsunami, they exceed the ground by the strength of the eruption. Currently, the vast majority of volcanic formations on the seabed are inactive.

The importance of tectonics for humans

In the life of mankind, the movements of the earth's crust play a huge role. And this concerns not only the formation of rocks, the gradual influence on the climate, but also the very life of entire cities.

For example, the annual transgression of Venice threatens the city by the fact that in the near future it will be under water. Such cases in history are repeated, many ancient settlements were submerged, and after a certain time they again appeared above sea level.