Earthquakes are a natural phenomenon that even today attracts the attention of scientists not only due to their little knowledge, but also due to their unpredictability, which can harm humanity.

What is an earthquake?

An earthquake is an earth tremor that can be felt by a person to a large extent, depending on the power of the earth's surface vibrations. Earthquakes are not uncommon and occur every day in different parts of the world. Often, most earthquakes occur at the bottom of the oceans, which avoids catastrophic destruction within densely populated cities.

The principle of earthquakes

What causes earthquakes? Earthquakes can be caused by both natural causes and man-made ones.

Most often, earthquakes occur due to faults in tectonic plates and their rapid displacement. For a person, the fault is not noticeable until the moment when the energy generated from the rupture of rocks begins to break out to the surface.

How do earthquakes occur due to unnatural causes? Quite often, a person, through his negligence, provokes the appearance of artificial shocks, which in their power are not at all inferior to natural ones. Among these reasons are the following:

• - explosions;
• - overfilling of reservoirs;
• - ground (underground) nuclear explosion;
• - collapses in mines.

The place where the tectonic plate breaks is the focus of the earthquake. Not only the strength of the potential shock, but also its duration will depend on the depth of its location. If the focus is located 100 kilometers from the surface, then its strength will be more than palpable. Most likely, this earthquake will entail the destruction of houses and structures. Originating in the sea, such earthquakes cause tsunamis. However, the focus can be located much deeper - 700 and 800 kilometers. Such phenomena are not dangerous and can be recorded only with the help of special instruments - seismographs.

The place where an earthquake is strongest is called the epicenter. It is this piece of land that is considered the most dangerous for the existence of all living things.

Studying earthquakes

A detailed study of the nature of earthquakes makes it possible to prevent many of them and make the life of the population living in dangerous places, more relaxed. To determine the power and measure the strength of an earthquake, two basic concepts are used:

• - magnitude;
• - intensity;

The magnitude of an earthquake is a measure that measures the energy released during release from the source in the form of seismic waves. The magnitude scale allows you to accurately determine the sources of fluctuations.

The intensity is measured in points and allows you to determine the ratio of the magnitude of shocks and their seismic activity from 0 to 12 points on the Richter scale.

Features and signs of earthquakes

Regardless of what causes an earthquake and in what area it is localized, its duration will be approximately the same. One push on average lasts 20-30 seconds. But there are cases in history when a single push without repetition could last up to three minutes.

Signs of an approaching earthquake are the anxiety of animals, who, having sensed the slightest vibrations of the earth's surface, try to get away from the unfortunate place away. Other signs of an imminent earthquake are:

• - the appearance of characteristic clouds in the form of oblong ribbons;
• - change of water level in wells;
• - failures in the work of electrical engineering, mobile phones.

How to behave during earthquakes?

How to behave during an earthquake to save your life?

• - Maintain composure and calmness;
• - When indoors, never hide under fragile furniture, such as under a bed. Lie next to them in a fetal position and cover your head with your hands (or protect your head with something extra). When the roof collapses, it will fall on the furniture and a layer may form, in which you will find yourself. It is important to choose sturdy furniture whose widest part rests on the floor, i.e. this furniture cannot fall;
• - When outdoors, move away from tall buildings and structures, power lines that can collapse.
• - Cover your mouth and nose with a wet cloth to prevent dust and fumes from entering if an object catches fire.

If you notice an injured person in a building, then wait for the tremors to end and only then make your way into the room. Otherwise, both people may be trapped.

Where there are no earthquakes and why?

Earthquakes occur when tectonic plates break. Therefore, countries and cities located on a solid tectonic plate without faults can not worry about their safety.

Australia is the only continent in the world that is not located at the junction of lithospheric plates. There are no active volcanoes and high mountains on it and, accordingly, there are no earthquakes. There are also no earthquakes in Antarctica and Greenland. The presence of the enormous gravity of the ice shell prevents the spread of tremors over the surface of the earth.

The likelihood of earthquakes in the territory Russian Federation quite high in rocky terrain, where the displacement and movement of rocks is most actively observed. Thus, high seismicity is noted in the North Caucasus, Altai, Siberia and the Far East.

Most of the largest earthquakes occur according to one scenario: rigid plate structures, consisting of earth's crust and mantles move by colliding with each other. In total, there are 7 largest plates in the world: Antarctic, Eurasian, Indo-Australian, North American, Pacific and South American.

Over the past two billion years, the movement of the plates has accelerated significantly, which, accordingly, increased the chances of such a catastrophe. On the other hand, based on studies of the movement of tectonic plates, scientists can, albeit approximately, predict the appearance of the next major earthquake. Based on those in open access From this data, we have estimated a list of cities where the probability of such an event is very high right now.

San Francisco

A powerful earthquake with an epicenter in the Santa Cruz Mountains, about a hundred kilometers from the city of San Francisco, is just around the corner. More specifically, over the next couple of years. However, most of the inhabitants of the City by the Bay prepared for the disaster by stocking up on medicines for the future, drinking water and food products. In turn, the city authorities are busy with the fact that they urgently carry out work to strengthen buildings.

Fremantle

Fremantle is a port city located on the west coast of Australia. According to seismological research by specialists from the University of Sydney, from the end of 2016 to 2024, a strong earthquake of about 6 on the Richter scale is expected there. However, the main danger is that the shock could occur at the bottom of the ocean near the city, causing a tsunami.

Tokyo

According to experts, a major earthquake with an epicenter in the Japanese capital with a probability of 75% can occur at any time within the next 30 years. According to the model created by scientists, about 23 thousand people will become a victim of the disaster and over 600 thousand buildings will be destroyed. In addition to improving the seismic resistance of buildings and demolishing old structures, the Tokyo administration will introduce non-combustible building materials. The 1995 Kobe earthquake showed the Japanese that people are more likely to fall victim not to collapsed buildings, but to post-disaster fires.

Los Angeles

Earthquakes in the City of Angels happen quite often, but there have been no truly large ones for more than a century. The more gloomy is the forecast presented by seismologists and geologists from the US Geological Society. Based on the analysis of soils and tectonic plates under central California, scientists concluded that before 2037 an earthquake of magnitude 6.7 could occur here. A push of such force, under certain circumstances, can turn a city into ruins.

Panama

Over the next few years powerful earthquake, with a power of more than 8.5 on the Richter scale will happen in the area of ​​the Isthmus of Panama. These conclusions were made by specialists from the University of San Diego, after they conducted seismological studies of faults adjacent to the Panama Canal. The action of an earthquake of truly catastrophic proportions will be felt by the inhabitants of both Americas. And most of all, of course, the capital of the republic, Panama, where about 1.5 million people live, will suffer.

Petropavlovsk-Kamchatsky

A strong earthquake in the medium term, that is, in the next 4-5 years, will occur in the area of ​​Petropavlovsk-Kamchatsky. Such data were reported in the seismology department of the Schmidt Institute of Physics of the Earth. In connection with this forecast, work is underway to strengthen buildings in Kamchatka, and the Ministry of Emergency Situations checks the seismic resistance of buildings. In addition, a network of stations was organized to monitor the symptoms of an approaching earthquake: high-frequency fluctuations in the earth's crust, water levels in wells, fluctuations in magnetic fields.

Grozny

According to the same department of seismology, a major earthquake in the period from 2017 to 2036. may occur in the North Caucasus, on the border of Chechnya and Dagestan. Unlike the situation in Kamchatka, no work is being carried out there to reduce the possible damage from earthquakes, which could lead to large quantity loss of life than if such work were carried out.

NY

New research results by American seismologists from Columbia University indicate a high seismic hazard at the present time in the vicinity of New York. The magnitude of the earthquake could reach five points, which could lead to the complete destruction of old buildings in the city. Another cause for concern was nuclear power plant, located right at the intersection of two faults, i.e. in an extremely dangerous region. Its destruction could make New York a second Chernobyl.

Banda Aceh

Indonesia is located in the most seismically active zone of the planet, and therefore you will not surprise anyone here with earthquakes. In particular, the island of Sumatra, constantly turns out to be almost right at the epicenter of tremors. An exception will not be a new earthquake predicted by seismologists, with an epicenter 28 km from the city of Banda Aceh, which will occur in the next six months.

Bucharest

The strongest earthquake in Romania can be provoked by blasting in shale rocks carried out in the Carpathian Mountains. Geophysicists from Romanian national institute report that the epicenter of the future earthquake will be in the same place, at a depth of 40 kilometers. The fact is that work to search for shale gas in these layers of the earth can cause displacements of the earth's crust and, as a result, earthquakes.

The earthly firmament has always been a symbol of security. And today, a person who is afraid of flying on an airplane feels protected only when he feels a flat surface under his feet. Therefore, it becomes the most terrible thing when, literally, the soil leaves from under your feet. Earthquakes, even the weakest ones, undermine the sense of security so much that many of the consequences are not of destruction, but of panic and are psychological, not physical. In addition, this is one of those disasters that humanity cannot prevent, and therefore many scientists are studying the causes of earthquakes, developing methods for fixing shocks, forecasting and warning. The amount of knowledge already accumulated by humanity on this issue allows minimizing losses in some cases. At the same time, examples of earthquakes recent years clearly show that there is still much to be learned and done.

The essence of the phenomenon

At the heart of each earthquake is a seismic wave, resulting in It arises as a result of powerful processes of various depths. Quite minor earthquakes occur due to surface drift, often along faults. Deeper in their location, the causes of earthquakes often have devastating consequences. They flow in zones along the edges of shifting plates that are subducting into the mantle. The processes taking place here lead to the most noticeable consequences.

Earthquakes happen every day, but people don't notice most of them. They are only fixed with special devices. In this case, the greatest force of shocks and maximum destruction occur in the epicenter zone, the place above the source that generated seismic waves.

Scales

Today, there are several ways to determine the strength of the phenomenon. They are based on such concepts as the intensity of an earthquake, its energy class and magnitude. The last of these is a value that characterizes the amount of energy released in the form of seismic waves. This method of measuring the strength of a phenomenon was proposed in 1935 by Richter and therefore is popularly called the Richter scale. It is still used today, but, contrary to popular belief, each earthquake is assigned not points, but a certain magnitude.

Earthquake scores, which are always given in the description of the consequences, refer to a different scale. It is based on a change in the amplitude of the wave, or the magnitude of the fluctuations in the epicenter. The values ​​of this scale also describe the intensity of earthquakes:

• 1-2 points: rather weak tremors, recorded only by instruments;
• 3-4 points: noticeable in high-rise buildings, often noticeable by the swinging of a chandelier and the displacement of small objects, a person may feel dizzy;
• 5-7 points: shocks can be felt already on the ground, cracks may appear on the walls of buildings, shedding of plaster;
• 8 points: powerful shocks lead to the appearance of deep cracks in the ground, noticeable damage to buildings;
• 9 points: the walls of houses are destroyed, often underground structures;
• 10-11 points: such an earthquake leads to collapses and landslides, the collapse of buildings and bridges;
• 12 points: leads to the most catastrophic consequences, up to a strong change in the landscape and even the direction of water movement in rivers.

Earthquake scores, which are given in various sources, are determined precisely on this scale.

Classification

The ability to predict any disaster is linked to a clear understanding of what causes it. The main causes of earthquakes can be divided into two large groups: natural and artificial. The former are associated with changes in the bowels, as well as with the influence of some cosmic processes, the latter are caused by human activity. The classification of earthquakes is based on the cause that caused it. Among the natural ones, tectonic, landslide, volcanic and others are distinguished. Let's dwell on them in more detail.

Tectonic earthquakes

The crust of our planet is constantly in motion. This is what causes most earthquakes. The tectonic plates that make up the crust move relative to each other, collide, diverge and converge. In places of faults, where plate boundaries pass and a compression or tension force arises, tectonic stress accumulates. Growing, sooner or later, it leads to the destruction and displacement of rocks, as a result of which seismic waves are born.

Vertical movements lead to the formation of dips or uplift of rocks. Moreover, the displacement of the plates can be insignificant and amount to only a few centimeters, but the amount of energy released in this case is sufficient for serious destruction on the surface. Traces of such processes on earth are very noticeable. These can be, for example, displacements of one part of the field relative to another, deep cracks and dips.

Under the water

The causes of earthquakes at the bottom of the ocean are the same as on land - the movements of lithospheric plates. Their consequences for people are somewhat different. Very often, the displacement of oceanic plates causes a tsunami. Having originated above the epicenter, the wave gradually gains height and often reaches ten meters near the coast, and sometimes fifty.

According to statistics, over 80% of tsunamis hit the shores of the Pacific Ocean. Today, there are many services in seismic zones, working on predicting the occurrence and propagation of destructive waves and alerting the population of danger. However, people are still little protected from such natural disasters. Examples of earthquakes and tsunamis at the beginning of our century are another confirmation of this.

Volcanoes

When it comes to earthquakes, involuntarily, images of the eruption of red-hot magma that were once seen appear in the head. And this is not surprising: two natural phenomena are interconnected. An earthquake can be caused by volcanic activity. The contents of the fiery mountains exert pressure on the surface of the earth. During the sometimes quite long period of preparation for the eruption, periodic explosions of gas and steam occur, which generate seismic waves. The pressure on the surface creates the so-called volcanic tremor (tremor). It is a series of small ground shaking.

Earthquakes are caused by processes occurring in the depths of both active volcanoes and extinct ones. In the latter case, they are a sign that the frozen fiery mountain can still wake up. Volcanic researchers often use micro-earthquakes to predict eruption.

In many cases, it is difficult to unambiguously attribute an earthquake to a tectonic or volcanic group. The signs of the latter are the location of the epicenter in the immediate vicinity of the volcano and a relatively small magnitude.

collapses

An earthquake can also be caused by the collapse of rocks. in the mountains arise as a result of various processes in the bowels and natural phenomena, as well as human activity. Hollows and caves in the ground can collapse and generate seismic waves. The collapse of rocks is facilitated by insufficient drainage of water, which destroys seemingly solid structures. The collapse could also be caused by a tectonic earthquake. The collapse of an impressive mass in this case causes insignificant seismic activity.

Such earthquakes are characterized by a small force. As a rule, the volume of collapsed rock is not enough to cause significant vibrations. Nevertheless, sometimes earthquakes of this type lead to noticeable damage.

Classification by depth of occurrence

The main causes of earthquakes are associated, as already mentioned, with various processes in the depths of the planet. One of the options for classifying such phenomena is based on the depth of their origin. Earthquakes are divided into three types:

• Surface - the source is located at a depth of no more than 100 km, approximately 51% of earthquakes belong to this type.
• Intermediate - the depth varies in the range from 100 to 300 km, the sources of 36% of earthquakes are located on this segment.
• Deep-focus - below 300 km, this type accounts for about 13% of such disasters.

The most significant marine earthquake of the third type occurred in Indonesia in 1996. Its center was located at a depth of more than 600 km. This event allowed scientists to "enlighten" the bowels of the planet to a considerable depth. In order to study the structure of the subsoil, almost all deep-focus earthquakes that are not dangerous for humans are used. Many data on the structure of the Earth were obtained as a result of studying the so-called Wadati-Benioff zone, which can be represented as a curved inclined line indicating the place where one tectonic plate enters under another.

Anthropogenic factor

The nature of earthquakes has changed somewhat since the beginning of the development of technical knowledge of mankind. In addition to natural causes that cause tremors and seismic waves, artificial ones also appeared. A person, mastering nature and its resources, as well as increasing technical power, by his activity can provoke a natural disaster. The causes of earthquakes are underground explosions, the creation of large reservoirs, the extraction of large volumes of oil and gas, resulting in voids underground.

One of the rather serious problems in this regard is earthquakes arising from the creation and filling of reservoirs. Huge in terms of volume and mass, the water column exerts pressure on the bowels and leads to a change in the hydrostatic equilibrium in the rocks. Moreover, the higher the created dam, the greater the likelihood of the so-called induced seismic activity.

In places where earthquakes occur for natural reasons, often human activity is superimposed on tectonic processes and provokes the occurrence of natural disasters. Such data imposes a certain responsibility on companies involved in the development of oil and gas fields.

Consequences

Strong earthquakes cause great destruction over vast areas. The catastrophicity of the consequences decreases with distance from the epicenter. The most dangerous results of destruction are various Collapse or deformation of industries associated with dangerous chemicals, leads to their release into environment. The same can be said about burial grounds and burial places. nuclear waste. Seismic activity can cause contamination of vast areas.

In addition to the numerous destruction in cities, earthquakes have consequences of a different nature. Seismic waves, as already noted, can cause collapses, mudflows, floods and tsunamis. Earthquake zones after a natural disaster often change beyond recognition. Deep cracks and sinkholes, soil erosion - these and other "transformations" of the landscape lead to significant environmental changes. They can lead to the death of the flora and fauna of the area. This is facilitated by various gases and metal compounds coming from deep faults, and simply by the destruction of entire sections of the habitat zone.

Strong and Weak

The most impressive destruction remains after mega-earthquakes. They are characterized by a magnitude of over 8.5. Such disasters are, fortunately, extremely rare. As a result of such earthquakes, some lakes and riverbeds were formed in the distant past. A picturesque example of the "activity" of a natural disaster is Lake Gek-Gol in Azerbaijan.

Weak earthquakes are a hidden threat. As a rule, it is very difficult to find out about the probability of their occurrence on the ground, while phenomena of more impressive magnitude always leave identification marks. Therefore, all industrial and residential facilities near seismically active zones are under threat. Such structures include, for example, many nuclear power plants and power plants in the United States, as well as burial sites for radioactive and toxic waste.

Earthquake regions

The uneven distribution of seismically hazardous zones on the world map is also associated with the peculiarities of the causes of a natural disaster. IN pacific ocean located seismic belt, with which, one way or another, an impressive part of earthquakes is connected. It includes Indonesia, the west coast of Central and South America, Japan, Iceland, Kamchatka, Hawaii, Philippines, Kuriles and Alaska. The second most active belt is the Eurasian one: the Pyrenees, the Caucasus, Tibet, the Apennines, the Himalayas, Altai, the Pamirs and the Balkans.

The earthquake map is full of other areas of potential danger. All of them are associated with places of tectonic activity, where there is a high probability of collision of lithospheric plates, or with volcanoes.

The earthquake map of Russia is also full of a sufficient number of potential and active sources. The most dangerous zones in this sense are Kamchatka, Eastern Siberia, the Caucasus, Altai, Sakhalin and the Kuril Islands. The most destructive earthquake in recent years in our country occurred on Sakhalin Island in 1995. Then the intensity of the disaster was almost eight points. The disaster led to the destruction of a large part of Neftegorsk.

The huge danger of a natural disaster and the impossibility of preventing it forces scientists around the world to study earthquakes in detail: the causes and consequences, "identification" signs and forecasting capabilities. Interestingly, technological progress, on the one hand, helps to more accurately predict terrible events, to capture the slightest changes in the internal processes of the Earth, and on the other hand, it also becomes a source of additional danger: accidents at hydroelectric and nuclear power plants, in mining sites, horrendous industrial fires. The earthquake itself is a phenomenon as ambiguous as scientific and technological progress: it is destructive and dangerous, but it indicates that the planet is alive. According to scientists, the complete cessation of volcanic activity and earthquakes will mean the death of the planet in geological terms. The differentiation of the bowels will be completed, the fuel that has been heating the interior of the Earth for several million years will run out. And it is not yet clear whether there will be a place for people on the planet without earthquakes.

An earthquake is a natural phenomenon with destructive power, it is an unpredictable natural disaster that occurs suddenly and unexpectedly. Earthquakes are tremors caused by tectonic processes occurring inside the earth, these are vibrations of the earth's surface that occur as a result of sudden ruptures and displacements of sections of the earth's crust. Earthquakes happen anywhere the globe, at any time of the year, it is virtually impossible to determine where and when, and how strong an earthquake will be.

They not only destroy our homes and change natural landscape, but also demolish cities and destroy entire civilizations, they bring people fear, grief and death.

How is the strength of an earthquake measured?

The intensity of tremors is measured in points. Earthquakes with a force of 1-2 points are caught only by special instruments - seismographs.

With an earthquake strength of 3-4 points, vibrations are already picked up not only by seismographs, but also by a person - objects around us, chandeliers, pots of flowers are swaying, dishes are ringing, cabinet doors are opening, trees and buildings are swaying, and the person himself is swaying.

At 5 points, it shakes even more, the wall clock stops, cracks appear on buildings, and plaster crumbles.

At 6-7 points, the fluctuations are strong, objects fall, paintings hanging on the walls, cracks appear on window panes and on the walls of stone houses.

Earthquakes of 8-9 points lead to the collapse of walls and the destruction of buildings and bridges, even stone houses are destroyed, and cracks form on the surface of the earth.

A 10-point earthquake has a more destructive character - buildings collapse, pipelines and railway lines break, landslides and collapses occur.

But the most catastrophic in terms of strength of destruction are earthquakes of 11-12 points.
In a matter of seconds, the natural landscape changes, mountains collapse, cities turn into ruins, huge sinkholes form in the earth, lakes disappear, and new islands can appear in the sea. But the most terrible and irreplaceable thing in such earthquakes is that people die.

There is also another more accurate objective way to assess the strength of an earthquake - by the magnitude of the vibrations caused by the earthquake. This value is called magnitude and determines the strength, that is, the energy of the earthquake, the highest value of magnitude is 9.

Source and epicenter of an earthquake

The force of destruction also depends on the depth of the earthquake source, the deeper the earthquake source occurs from the surface of the earth, the less destructive force the seismic waves carry.

The focus arises at the place of displacement of giant rock masses and can be located at any depth from eight to eight hundred kilometers. It doesn’t matter at all whether this displacement is large or not, vibrations of the earth’s surface still occur and how far these vibrations spread depends on their energy and forces.

The greater depth of the earthquake source reduces the destruction on the earth's surface. The destructiveness of an earthquake also depends on the size of the source. If the vibrations of the earth's crust are strong and sharp, then catastrophic destruction occurs on the surface of the earth.

The epicenter of an earthquake should be considered a point above the focus, located on the surface of the earth. Seismic or shock waves diverge from the source in all directions, the farther from the source, the less the intensity of the earthquake. The speed of shock waves can reach eight kilometers per second.

Where do earthquakes most often occur?

What corners of our planet are more seismically dangerous?

There are two belts where earthquakes occur most often. One belt starts at the Sunda Islands and ends at the Isthmus of Panama. This is the Mediterranean belt - it stretches from east to west, passes through mountains such as the Himalayas, Tibet, Altai, Pamir, the Caucasus, the Balkans, the Apennines, the Pyrenees and passes through the Atlantic.

The second belt is called the Pacific. This is Japan, the Philippines, it also covers the Hawaiian and Kuril Islands, Kamchatka, Alaska, Iceland. Passes along the western coasts of North and South America, through the mountains of California, Peru, Chile, Tierra del Fuego and Antarctica.

There are also seismically active zones on the territory of our country. This North Caucasus, Altai and Sayans, Kuril Islands and Kamchatka, Chukotka and Koryak Highlands, Sakhalin, Primorye and Amur Region, Baikal zone.

Earthquakes also often occur near our neighbors - in Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, Armenia and other states. Yes, and in other areas that are distinguished by seismic stability, tremors periodically occur.

The seismic instability of these belts is associated with tectonic processes in the earth's crust. Those territories on which there are active smoking volcanoes, where there are mountain ranges and the formation of mountains continues, there are most often the centers of earthquakes and tremors often occur in those places.

Why earthquakes happen

Earthquakes are the result of tectonic movement occurring in the depths of our Earth, there are many reasons why these movements occur - this is external influence space, the sun, solar flares and magnetic storms.

This, and the so-called ground waves, which periodically arise on the surface of our earth. These waves are clearly visible on the sea surface - sea tides. On the earth's surface, they are not noticeable, but are fixed by instruments. Ground waves cause deformation of the earth's surface.

Some scientists suggest that the moon may be the culprit of earthquakes, or rather, the vibrations occurring on the lunar surface, they also affect earth's surface. It was observed that strong destructive earthquakes coincided with the full moon.

Scientists also point out natural phenomena that precede earthquakes are strong, prolonged precipitation, large atmospheric pressure drops, unusual air glow, restless behavior of animals, as well as an increase in gases - argon, radon and helium and uranium and fluorine compounds in groundwater.

Our planet continues its geological development, young mountain ranges are growing and forming, in connection with human activity, new cities appear, forests are destroyed, swamps are drained, new reservoirs appear, and the changes that occur in the depths of our Earth and on its surface cause all kinds of natural disasters.

Human activities also have a negative impact on the mobility of the earth's crust. A person who imagines himself a tamer and creator of nature, thoughtlessly intervenes in the natural landscape - demolishes mountains, erects dams and hydroelectric stations on rivers, builds new reservoirs, cities.

Yes, and mining - oil, gas, hard coal, building materials - crushed stone, sand - affects seismic activity. And in those areas where the likelihood of earthquakes is high, seismic activity is further enhanced. With his ill-conceived actions, a person provokes landslides, landslides and earthquakes. Earthquakes that occur due to human activity are called technogenic.

Another type of earthquake occurs with the participation of man. During underground nuclear explosions, when tectonic weapons are being tested, or during the explosion of a large number of explosives, the earth's crust also fluctuates. The intensity of such tremors is not very great, but they can provoke an earthquake. Such earthquakes are called artificial.

There are still volcanic earthquakes and landslide. Volcanic earthquakes are caused by high stress in the interior of a volcano, and these earthquakes are caused by volcanic gas and lava. The duration of such earthquakes is from several weeks to several months, they are weak and do not pose a danger to people.
Landslide earthquakes are caused by large landslides and collapses.

Earthquakes occur daily on our Earth, about a hundred thousand earthquakes a year are recorded by instruments. This incomplete list of catastrophic earthquakes that occurred on our planet clearly shows what kind of losses mankind suffers from earthquakes.

Catastrophic earthquakes that have occurred in recent years

1923 - Japan, the epicenter near Tokyo, killed about 150 thousand people.
1948 - Turkmenistan, Ashgabat was completely destroyed, about a hundred thousand dead.
1970 in Peru, a landslide caused by an earthquake killed 66,000 people in the city of Yungai.
1976 - China, the city of Tiangshan is destroyed, 250 thousand dead.

1988 - Armenia, the city of Spitak was destroyed - 25 thousand people died.
1990 - Iran, Gilan province, 40 thousand dead.
1995 - Sakhalin Island, 2 thousand people died.
1999 - Türkiye, the cities of Istanbul and Izmir - 17 thousand dead.

1999 - Taiwan, 2.5 thousand people died.
2001 - India, Gujarat - 20 thousand dead.
2003 - Iran, the city of Bam was destroyed, about 30 thousand people died.
2004 - the island of Sumatra - an earthquake and tsunami caused by an earthquake killed 228 thousand people.

2005 - Pakistan, Kashmir region - 76 thousand people died.
2006 - the island of Java - 5700 people died.
2008 - China, Sichuan province, 87 thousand people died.

2010 - Haiti, -220 thousand people died.
2011 - Japan - an earthquake and tsunami claimed the lives of more than 28 thousand people, explosions at the Fukushima nuclear power plant led to an environmental disaster.

The most powerful shocks destroy the infrastructure of cities, buildings, depriving us of housing, bring enormous damage to the inhabitants of those countries where the elements broke out, but the most terrible and irreparable is the death of millions of people. History preserves the memory of destroyed cities, vanished civilizations, and no matter how terrible the power of the elements, a person, having survived the tragedy, restores his housing, builds new cities, builds new gardens and revives the fields on which he grows his livelihood.

How to behave during an earthquake

At the first shocks of an earthquake, a person experiences fear, confusion, because everything around starts to move, chandeliers sway, dishes rattle, cabinet doors open, and sometimes objects fall, the earth leaves from under his feet. Many panic, begin to rush about, others, on the contrary, hesitate, freeze in place.

If you are on 1-2 floors, the first thing you should do is to try to leave the premises as soon as possible and move to a safe distance from buildings, try to find an open place, pay attention to power lines, you can’t be under them, with strong jolts wires can break and you can get an electric shock.

If you are above the 2nd floor or have not had time to jump out into the street, try to leave the corner rooms. It is better to hide under the table or under the bed, stand in the opening of internal doors, in the corner of the room, but away from cabinets and windows, as broken glass and objects in the cabinets, and the cabinets themselves, refrigerators, when falling, can hurt and injure you.

If you still decide to leave the apartment, then be careful not to enter the elevator, during strong earthquakes the elevator can turn off or collapse, and it is also not advised to run to the stairs. Flights of stairs can be damaged due to an earthquake, and a crowd of people rushing to the stairs will increase the load on them and the stairs may collapse. Going out on balconies is just as dangerous, they can also collapse. Do not jump out of windows.

If tremors caught you on the street, move to an open space, away from buildings, from power lines, from trees.

If you are in a car, stop at the side of the road, away from lights, trees, billboards. Do not stop in tunnels, under wires and bridges.

If you live in a seismically active area and earthquakes periodically shake your homes, then you should prepare yourself and your family for the possibility of a stronger earthquake. Determine in advance the safest areas in your apartment, take measures to strengthen your home, teach children how to behave if children are at home alone during tremors.

Recently I helped my little son with a small report on this topic. Despite the fact that I know enough about this phenomenon, the discovered information turned out to be extremely interesting. I will try to accurately convey the essence of the topic and talk about how How are earthquakes classified?. By the way, the son proudly brought five from school. :)

Where do earthquakes occur

First you need to understand what is commonly called an earthquake. So, scientifically speaking, these are strong vibrations on the surface of our planet, due to the processes that take place in the lithosphere. Areas where high mountains are located are the places where this phenomenon is observed most often. The thing is that the surfaces in these areas are at the stage of formation, and bark is most mobile. Such areas are called places. rapidly changing relief, however, many earthquakes were observed on the plains.

What are earthquakes

Science distinguishes several types of this phenomenon:

• tectonic;
• collapse;
• volcanic.

Earthquake of a tectonic type- a consequence of the displacement of mountain plates, which is due to the collision of two platforms: continental and oceanic. This species is characterized formation of mountains or depressions, as well as surface vibrations.

As for earthquakes volcanic type, then they are due to the pressure of gases and magma on the surface from below. Usually the shocks are not very strong, however can go on long enough. Tellingly, this species is a harbinger of a more destructive and dangerous phenomenon - volcanic eruptionA.

Landslide earthquake occurs as a result of the formation of voids, which can be formed by the movement of groundwater. In this case the surface just collapses, which is accompanied by small tremors.

Intensity measurement

According to Richter scale it is possible to classify an earthquake based on the energy that is carried seismic waves. It was proposed in 1937 and eventually spread throughout the world. So:

1. not felt- shocks are not caught at all;
2. very weak- is registered only by devices, a person does not feel;
3. weak- can be felt while in the building;
4. intensive- accompanied by a slight displacement of objects;
5. almost strong- felt in open spaces sensitive people;
6. strong- felt by all people;
7. very strong- small cracks appear in the brickwork;
8. destructive- serious damage to buildings;
9. devastating- huge destruction;
10. destroying- dips in the ground up to 1 meter are formed;
11. catastrophic- buildings are destroyed to the foundation. Cracks over 2 meters;
12. catastrophe- the entire surface is indented with cracks, rivers change their channels.

According to seismologists - scientists who study this phenomenon, about 400,000 events per year earthquakes of various strengths.