Eurasian lithospheric plate on the map. Basic principles of the theory

Most people have at least a vague and most general idea that the earth’s surface is not at all monolithic, not “solid earth,” to use the old expression, but a system of plates interacting with each other. Most often in conversations at the everyday level, the phrase “tectonic plates” is used, which should reflect the moving nature of this system (tectonics is, among other things, the history of the movement of the plates that make up the earth’s surface). The Earth's surface is indeed made of plates, but there are no tectonic plates.

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Let us increase this value of our life every day, because death can suddenly throw us off at any time. We will strive for perfection, unite personal choice and activity with the main goal of our existence - spiritual and moral transformation, serving the highest ideological divine values.

Lithospheric plates - yes, tectonic plates - no

300 million years ago, plate movement created a single terrestrial continent, Panagea, which was surrounded by a single ocean, Panthalassa. About 100 million years ago, Panagea began to break apart to form the modern continents

In fact, there was confusion with the concepts. There is a concept of the lithosphere, that is dura shell land. There is a concept of lithospheric plates - the largest and most stable sections of the lithosphere, earth's surface. And there is the concept of “plate tectonics,” which means modern scientific discipline, which studies the movement of lithospheric plates relative to each other.

Scientists now know that the Apennine Peninsula, which is also home to states such as San Marino and Vatican City, lies at the junction of three tectonic plates: African, Eurasian and Adriatic. As a result, this area is characterized by rock formations, volcanic and seismic activity.

Tectonic structure of the Apennine Peninsula. The Adriatic microregion was once separated from the African plate by the so-called transformation break, which led to a new breakthrough along the edge of the lithospheric plate. The Admiral plate continues to move towards the Eurasian plate and the “runners” under the Apennine mountains, moving from east to west, rotating clockwise and creating stress in earth's crust. A periadriatic break passing through the Alps separates these two plates. Part of the oceanic crust of the African plate is subject to subduction southern edge The Adriatic plate, which led to the formation of volcanoes in southern Italy.

According to the theory based on plate tectonics, new crust appears in expansion zones on the ocean floor, dura shell Earth, and in subduction zones the old crust is absorbed. The philistine consciousness mixed the idea of ​​lithospheric plates and the scientific theory of their constant movement (plate tectonics): as a result, “tectonic plates” appeared, which are more correctly called “moving lithospheric plates.”

It is known that the African plate is slowly but surely falling to the bottom. It is unlikely that Africa will go down, but Africa and Europe are still getting closer. The question remains how they meet - Rin Wortel, Utrecht University. Arrows indicate compression and tension zones. The following figure shows the tectonic structure of Europe and the Middle East. After all, processes in the earth's crust are interconnected. Thus, an increase in activity in one area can lead to a natural increase in activity in another area.

Tectonic structure of Europe and the Middle East. Due to its complex geological structure, Italy is at risk. Increased seismic activity. There are 13 volcanoes in Italy, three of which are giant - Vesuvius, Stromboli and Etna. It also includes the coastal strip of the Tyrrhenian Sea near the city of Kuma and the islands of Nishida, Procida, Ischia and Vivara.

Currently, plate tectonics presents the following picture. The modern lithosphere is divided into many lithospheric plates, but 90% of the earth's surface is divided into eight main plates. The earth's surface is of two types: oceanic crust (younger, as it is constantly renewed) and continental crust (more ancient).

The last caldera activity was recorded in November. But we must not forget about the other active tectonic and volcanic phenomena mentioned above on the Apennine Peninsula. Scientists studying images taken from space concluded that the area adjacent to Norcia moved west by about 30 cm, and the area around Montegallo moved east by about 40 cm in the east.

All these processes indicate impending global cataclysms on planet Earth, which all humanity must prepare in advance. If we talk about preparation, we do not mean building bunkers, but cleaning up interpersonal relationships and restoring the atmosphere in society. If people submit to each other the hand of friendship and help, then even in difficult climatic trials it will be much easier for each of us to survive with dignity and make a choice in favor of unity and friendship between all peoples of the world.

The plates on which the continents stand continue to move to this day - several centimeters per year

Lithospheric plates can carry out Various types movements relative to each other, there are three main types of movement: first, divergence, that is, the discrepancy between the plates; secondly, convergence, that is, convergence, rapprochement between plates; thirdly, shear movements along transform geological faults. Scientists currently believe that plate tectonics does not play a decisive role in global climate change. , however, may have an auxiliary effect on these processes.

Uniting people around the world based on spiritual and moral values ​​can change the course of history. “For companies such dreams, people always, in their legends call it” good soil, the state of bliss, the golden millennium, the world of justice, the Millennium, the future, which can be brought through divine intervention, but will only be achieved through human actions - from the book “AllatRa”.

Prepared by: Ekaterina Agezhchenko and Vitaly Afanasyev. We don't have much fear of an earthquake in northern Europe. We are ready to admit that in a distant foreign country, Japan, Indonesia or South America, the seismic element is real danger, destroying human lives and property; but our “earthquake” - if we ever feel it - most often we associate only with glass glasses, with cracks in plaster or - without stones - with some broken chimney.

The plates on which humanity lives

The main, largest and most stable areas of the earth's surface are eight lithospheric plates:

  • Indo-Australian plate - it contains Australia and the surrounding part of the ocean, reaching the Hindustan Peninsula. Currently, the movement of this lithospheric plate to the east from the north is noted at a speed of 67 millimeters per year;
  • Antarctic plate - occupies southern part planet, it contains Antarctica and adjacent areas of the oceanic crust. This plate is relatively stable because it is surrounded by mid-ocean ridges, and other lithospheric plates are moving away from it;
  • African plate - it contains the African continent, as well as a section of oceanic crust that occupies part of the floor of the Indian and Atlantic oceans. At the same time, in its northeastern part, this plate actually splits - the territory of the Arabian Peninsula already constitutes almost a separate plate. The lithospheric plates adjacent to the African plate are moving away from it, while in the northern part it itself is sinking into the mantle at a speed of 27 millimeters per year (the process of sinking plates into the mantle is subduction);
  • Eurasian plate - the main territory of the Eurasian continent is located on it; this plate does not include the Hindustan Peninsula, the Arabian Peninsula and the northeastern “corner” of the continent. The largest continental crust in terms of content lithospheric plate on the ground;
  • Indian plate - the Hindustan Peninsula is located on it, this medium-sized plate about 90 million years ago began to move from Madagascar to the north at a speed of 200 millimeters per year (such a high speed is due to the smaller thickness of the plate), and about 50 million years ago the process of its collision began with the Eurasian plate. As a result of the collision, the Tibetan Plateau and the Himalayas appeared. The Indian plate continues to move northeast at a speed of 50 millimeters per year, while the Eurasian plate “runs away” from it to the north at a speed of only 20 millimeters per year. In addition, the Indian plate has three subduction zones: in one it sinks into the mantle at a rate of 55 millimeters per year, in another at a rate of 67 millimeters per year, in the third at a speed of 87 millimeters per year;
  • Pacific plate - it contains a section of oceanic crust that makes up the bottom Pacific Ocean. In the California region, the plate is moving north at a speed of 55 millimeters per year. At the same time, the size of the Pacific Plate is constantly decreasing due to the fact that it has several subduction zones at once: under the Eurasian Plate it is sinking into the mantle at a speed of 75 millimeters per year; under Indian - at a speed of 82 millimeters per year; under the North American - at a speed of 35 millimeters per year; under the medium-sized Philippine lithospheric plate - at a speed of 12 millimeters per year;
  • North American Plate - it contains the North American continent, the northwestern part of the Atlantic Ocean, about half of the Arctic Ocean and the northeastern “corner” of Eurasia;
  • The South American Plate, which contains South America and part of the Atlantic Ocean floor, was formed about 70 million years ago as a result of the breakup of the ancient supercontinent Gondwana. It has a subduction zone in which the crust sinks into the mantle at a rate of 19 millimeters per year and 5 millimeters per year.

Alexander Babitsky

All you have to do is cross the Alps in south direction, and suddenly we find ourselves in a region of unburnt natural elements. Today it is marked by the highest degree of macroseismic intensity, respectively. with a very large magnitude of 9. It was one of the six strongest earthquakes in the world of all time, reaching a magnitude of nine.

Perhaps this will catch us: because Lisbon is not so far from the Czech Republic. Don't we even need to worry about the dynamic seismic manifestations of wrathful mother Gaia? For a seamless Europe, seismic hazards of such a high degree are not at risk.

Discovery of continental drift.

World map showing the location of the main lithospheric plates. Each plate is surrounded by oceanic ridges,
from the axes of which there is tension (thick lines), zones of collision and subduction (jagged lines) and/or
transform faults (thin lines). Names are given only for some of the most large slabs.
The arrows indicate the directions of relative plate movements.

Most of the destructive earthquakes in the Mediterranean and Atlantic Oceans lie in the seismically active rupture zone separating the tectonic plates of Eurasia and Africa, which are moving towards each other. It is clear that such two colossi in contact, which are not smooth, must from time to time “break away” from the irregularities and then “cut” it. It's just the kind of jump that creates strong earthquakes. Confirmation of the cause of the earthquake in this border zone is not only Lisbon, but also Calabrian, Sicilian, Messina, Dubrovnik and many Greek and Western Anatolian earthquakes.

At the beginning of the 20th century, a German meteorologist Alfred Wegener began to collect and study information about the flora and fauna of the continents separated by the Atlantic Ocean. He also carefully examined everything that was then known about their geology and paleontology, about the fossil remains of organisms found on them. After analyzing the data obtained, Weneger came to the conclusion that various continents, including South America and Africa, formed a single whole in the distant past. He discovered, for example, that some geological structures South America, which abruptly end with the coastline of the Atlantic Ocean, have, as it were, a continuation in Africa. He cut out these continents from the map, moved these cuttings towards each other and saw that the geological features of these continents coincided, as if continuing each other.

All these boundaries between two tectonic giants, for which the collision zone is known, are very clearly defined. This collision zone is so far from Arctic Europe that it poses no immediate seismic hazard. In Central and Northern Europe, predominantly local faults within the Eurasian tectonic plate are seismically active. However, in most cases they cannot accumulate the tectonic stress necessary for a truly large earthquake.

Lisbon was one of the most impressive and wealthy cities in Europe at mid-century. From Lisbon, the capital of the Kingdom of Portugal, ships sailed for centuries to the coasts of South America and around Africa to South-East Asia. Soon, in the opposite direction, boats filled the treasures of these areas, many of which became Portuguese colonies.

He also discovered that there were geological signs of an ancient glaciation that affected Australia, India and South Africa at about the same time, and noted that it was possible to combine these continents in such a way that their glaciated areas would form a single area. Based on his research, Wegener published the book “The Origin of Continents and Oceans” in Germany (1915), in which he put forward his theory of “continental drift.” But the author of this book could not defend his theory convincingly enough; he selected some facts to support it quite arbitrarily. Largely for these reasons, his hypothesis was not accepted by most scientists at the time. For example, eminent physicists of that time stated that continents cannot drift like ships at sea, since the outer parts of the lithosphere are very rigid. They also pointed out that the centrifugal forces resulting from the Earth's rotation on its axis were too weak to move the continents, as Wegener assumed.

They participated in religious services in large numbers, and the cooks of the house prepared a festive meal in molten ovens. The strong blows lasted a relatively long time: 2.5-6 minutes. The walls began to crumble, the ceilings and vaults were falling, the houses were boring. People were crushed under the rubble. Violent shocks struck Lisbon for several days, the strongest between one and the other, strong movements in the afternoon demolishing houses until they broke.

The city, as in the biblical story of Job, received four wounds. The first shock - repeated impacts of seismic waves - almost coincided with the entire area of ​​the city, especially the parts built on the floodplains. The energy shifted towards them, and the movements of the soil were most destructive. Buildings built on two geologically more compact slopes of the city's central reservoir suffered less fatal damage. About 85% of the city's buildings were destroyed or severely damaged.

But Wegener was still on the right track. The revival of Wegener's ideas in the form of the theory of plate tectonics occurred in the 1950s and 1960s. During these years, studies of the ocean floor, which began during the Second World War, were carried out. American Navy, while developing submarines, was very interested in learning as much as possible about the ocean floor. Perhaps this is a rare case when military interests benefited science. At that time, and even until the 1960s, the ocean floor was almost unexplored territory. Geologists said then that we know more about the surface of the Moon facing us than about the seabed. The US Navy was generous and paid well. Oceanographic research quickly became widespread. Although a significant part of the research results was classified, the discoveries made pushed Earth science to a new, more high level understanding the processes occurring on Earth.

After this terrible situation, many people sought safety in boats and boats on the calm Tagus River. But this soon turned out to be a fatal decision. About 30 minutes after the arrival of the seismic waves, in the distance, at the mouth of the Tagus to the Atlantic, the Bugio Tower saw a tall torpedo wave running at high speed upstream from the river. There was no time to save the river. Within a few short minutes, there was a 20-foot wall of water on the coastal front of the house. Later flood waves were even higher, estimated at 12 metres.

The royal palace, built on the river embankment, was badly damaged. In the city center, flooding reached Rossi Square today. However, the sea flooding was not limited to Lisbon. Most of the affected coastal cities are in the southwestern part of the country. Tsunami waves reached up to 30 meters. Heavy damage and loss of life also caused a tsunami in the Moroccan coastal city of Norta, where waves reached 20 meters above. The inland cities of Meknes and Fez also suffered seismic damage.

One of the main results of intensive research of the ocean floor has been new knowledge about its topography. Previous knowledge of the seabed, accumulated over a long history of sea voyages, was extremely insufficient. The most first depth measurements were made using the simplest methods - measuring cables. The lot was thrown overboard and the length of the etched cable was measured. But these measurements were limited to shallow, coastal areas.

Low tsunamis have been reported in the Azores and even along the Brazilian coast and the Caribbean. Influence inland waters also struck Western and northern Europe: Lakes and water areas in England, Scotland, the Netherlands, Switzerland, Sweden and Finland were greatly degraded during the passage of seismic waves.

The consequences of the earthquake manifested themselves on our territory. Seismic waves, passing through the northern regions of Bohemia, “caught up” mineral springs in the spa gardens of Teplice, which grew among the stone blocks. However, less than half an hour later, the ever-increasing pressure in the groundwater broke through again, and the spring was restored with a double output.

At the beginning of the 20th century, echo sounders appeared on ships, which were continuously improved. Measurements carried out in the 1950s and 1960s using echo sounders provided a lot of information about the topography of the ocean floor. The principle of operation of an echo sounder is to measure the time required for a sound pulse to travel from the ship to the seabed and back. Knowing the speed of sound in sea water, it is easy to calculate the depth of the sea at any place. The echo sounder can operate continuously, around the clock, no matter what the ship is doing.

The many stoves, ovens and fireplaces melted during the preparation of Sunday dinner were the source of numerous fires, confirmed by modern engravings. In Lisbon it was used as a wood material from the Brazilian forests, a wood that was mechanically strong, tough, exotic in color and could be well sanded and polished. This hardwood, once ignited, was difficult to quench. The fight against the fire lasted endlessly for five days in Lisbon.

The final blow was the proliferation of destroyed houses, palaces and churches and the merciless plunder of not only the dead, but even living wounded fellow citizens. Portuguese sources report that as soon as the report of the destruction of Lisbon spread throughout neighboring countries, criminal elements from Portugal and neighboring Spain began filming and embarrassing to do their dirty work. However, the then Prime Minister Sebastian José de Carvalho y Mello, known as the Marquis of Pombal, who had gallows built on top of the city, was vigorously prevented. The 34 executed soldiers were executed and the looting ended.

Nowadays, the topography of the ocean floor has become easier to map: equipment installed on Earth satellites accurately measures the “height” of the sea surface. There is no need to send ships to sea. Interestingly, the differences in sea level from place to place accurately reflect the topography of the seafloor. This is explained by the fact that slight variations in gravity and the bottom affect the sea surface level in a particular place. For example, over a place where there is a large volcano of enormous mass, the sea level rises compared to neighboring areas. On the contrary, above a deep ditch or basin, the sea level is lower than above raised areas of the seabed. It was impossible to “consider” such details of the seabed relief when studying it from board ships.

The results of research of the seabed in the 60s of the 20th century raised many questions for science. Until this time, scientists believed that the bottom of the deep seas were calm, flat areas of the earth's surface, covered with a thick layer of silt and other sediments washed away from the continents over an infinitely long time.

However, the received research materials showed that the seabed has a completely different topography: instead of a flat surface on the ocean floor, mountain ranges of enormous length, deep ditches (rifts), steep cliffs and largest volcanoes. In particular, Atlantic Ocean exactly in the middle is dissected by the Mid-Atlantic Ridge, which repeats all the protrusions and depressions coastline on each side of the ocean. The ridge rises on average 2.5 km above the most deep places ocean; Almost along its entire length, along the axial line of the ridge, there is a rift, i.e. a gorge or valley with steep sides. In the North Atlantic Ocean, the Mid-Atlantic Ridge rises above the ocean's surface to form the island of Iceland.

This ridge is only part of a system of ridges that stretches across all the oceans. The ridges surround Antarctica, extending in two branches into Indian Ocean and to the Arabian Sea, bend along the shores of the eastern Pacific Ocean, approach lower California, and appear off the coast of the northwestern United States.

Why was this system of underwater ridges not buried under a layer of sediment carried from the continents? What is the connection between these ridges and the drift of continents and tectonic plates?

The answers to these questions are obtained from the results of a study ... of the magnetic properties of the rocks that make up the ocean floor. Geophysicists, wanting to know as much as possible about the seabed, along with other work, were engaged in measuring the magnetic field along numerous routes of research ships. It was discovered that, unlike the structure of the magnetic field of continents, which is usually very complex, the pattern of magnetic anomalies on the ocean floor differs in a certain pattern. The reason for this phenomenon was not clear at first. And in the 60s of the 20th century, American scientists conducted an aerial magnetic survey of the Atlantic Ocean south of Iceland. The results were striking: magnetic field patterns above the seafloor varied symmetrically around the centerline of the ridge. At the same time, the graph of changes in the magnetic field along the route crossing the ridge was basically the same on different routes. When the measurement points and measured magnetic field strengths were plotted on a map and isolines (lines of equal values ​​of magnetic field characteristics) were drawn, they formed a striped zebra-like pattern. A similar pattern, but with less pronounced symmetry, was previously obtained when studying the magnetic field in the northeastern part of the Pacific Ocean. And here the nature of the field differed sharply from the structure of the field above the continents. As scientific data accumulated, it became clear that symmetry in the magnetic field pattern was observed throughout the ocean ridge system. The reason for this phenomenon lies in the following physical processes.

Rocks erupted from the Earth's interior cool from their original molten state, and the iron-containing materials formed in them are magnetized by the Earth's magnetic field. All elementary magnets of these minerals are oriented in the same way under the influence of the surrounding magnetic field of the Earth. This magnetization is a continuous process in time. This means that a graph of the magnetic field along a route crossing a ridge is a kind of fossil record of changes in the magnetic field during the formation of rocks. This record is stored for a long time. As would be expected, geophysical surveys along routes directed perpendicular to the location of the Mid-Atlantic Ridge have shown that rocks located exactly above the ridge axis are highly magnetized in the direction of the Earth's modern magnetic field. The symmetrical zebra-shaped magnetic field pattern indicates that the seafloor is magnetized differently in different areas parallel to the direction of the ridge. We are talking not only about the different strength (intensity) of the magnetic field of different sections of the seabed, but also about the different direction of their magnetization. This has already become a major scientific discovery: it turned out that the Earth’s magnetic field has repeatedly changed its polarity over the course of geological time. Evidence of the periodic change of the Earth's magnetic poles was also obtained by studying the magnetization of rocks on the continents. It was found that in areas where large basalt masses accumulate, one part of the basalt flows has a direction of magnetization corresponding to the direction of the modern magnetic field of the Earth, while other flows are magnetized in the opposite direction.

It became clear to researchers that seafloor magnetic stripes, magnetic polarity fluctuations and continental drift are all interconnected phenomena. The zebra-shaped pattern of magnetization distribution of seafloor rocks reflects the sequence of changes in the polarity of the earth's magnetic field. Most geologists are now convinced that seafloor movement away from ocean faults is a reality.

New oceanic crust is formed by lava that continuously flows from deep within the axial parts of oceanic ridges. The magnetic pattern of the seafloor rocks is symmetrical on both sides of the ridge axis because the newly arrived portion of lava is magnetized when it solidifies into solid rock and expands evenly on both sides of the median fault. Since the dates of changes in the polarity of the Earth's magnetic field have become known as a result of the analysis of rocks on land, the magnetic stripes of the ocean floor can be considered as a kind of time scale.

During its eruption along the ridge and subsequent solidification, the basalt becomes magnetized
under the influence of the Earth's magnetic field and then diverges away from the fault.

The rate of emergence of a new section of the seabed can be quite simply calculated by measuring the distance from the ridge axis, where the age of the seabed is zero, to the stripes corresponding to known periods of reversal of the magnetic field polarity.

The rate of formation of the seabed varies from place to place; its value, calculated from the location of the magnetic stripes, averages several centimeters per year. Continents located on opposite sides of the Atlantic Ocean are moving away from each other at this speed. For this reason, the oceans are not covered with a thick layer of sediment; they (the oceans) are very young on a geological scale. At a speed of a few centimeters per year (this is very slow, of course), the Atlantic Ocean could have formed in two hundred million years, which by geological standards is not that long. The bottom of any of the oceans existing on Earth is not much older. Compared to the rocks of the continents, the age of the ocean floor is much younger.

Thus, it has been proven that the continents on both sides of the Atlantic Ocean are moving apart at a rate that depends on the rate of formation of new sections of the seabed on the axis of the Mid-Atlantic Ridge. Both the continents and the oceanic crust move together as one because... they are parts of the same lithospheric plate.

Vladimir Kalanov,
"Knowledge is power"