Earthquake classes and types, causes and consequences, map and scale of earthquakes


An earthquake (also called a seismic shock) is a natural phenomenon that consists in tremors and vibrations of the earth’s crust. Tremors occur due to sudden displacement or rupture of the upper parts of the lithospheric plates or mantle. They are transmitted over considerable distances and can greatly affect human life.  The hypocenter of an earthquake is the point in the earth’s crust that is the beginning of seismic waves that travel further. The epicenter of seismic shocks is the place above the hypocenter, located in the shortest distance.

Causes and factors of earthquakes

Various events take place on our planet every day, and there are no exceptions in the natural world: dozens of earthquakes occur on Earth every day. Most of them are moderate and underground, which is why people may not notice them at all, since the sensation on the surface develops in a slightly different way. But those seismic tremors, the amplitude of which ranges from 4 to 5, are already beginning to be felt by the inhabitants of the globe, but massive destruction does not occur. The amplitude of 6-7 is already quite dangerous and only a couple of hundred of such cases are recorded per year. Magnitude 8 and above is already classified as a full-fledged natural disaster and occurs up to ten times a year. The most destructive earthquakes are considered to be magnitude 9 earthquakes, and they occur once every thirty years.

Since our planet is primarily a cosmic body, many internal processes are hidden from human eyes. One of these is the differentiation of matter inside the magma, as a result of which various cold substances begin to sink in the bowels of the Earth, and warm ones rise. Such processes cause stress in the earth’s crust, and the lithosphere eventually accumulates a large amount of stress, which is further discharged in the form of cracks and waves.

The consequences of earthquakes

The stronger the power of the earthquake, the greater the consequences come from them. Due to natural disasters, the infrastructure of cities suffers, buildings collapse, mountains collapse, which further bring devastation, and subsequent disasters occur, for example, floods or fires. Many people have died from earthquakes and their consequences throughout our existence. But in addition to physical destruction and obvious casualties, seismic waves affect human health. Many studies by scientists around the world have confirmed the theory that some “sensitive” people feel the approach of something terrible and they get a headache or a fever. It was these people who were once considered magicians and shamans, because they literally predicted the approach of trouble, using only internal sensations. Of course, all this may be a coincidence, no one denies, but given the amount of research and the time that bright minds have spent on them, it is hard to believe in such coincidences of circumstances.

In addition to physical, psychological and other problems, earthquakes also have environmental consequences. Thus, many landslides, collapses, avalanches and other smaller-scale, but no less dangerous disasters occur in the world. Changing the landscape as a result of strong seismic shocks can lead to the destruction of entire villages and cities, as well as the destruction of plant and animal cultures. The relief begins to change, the water in various reservoirs is blocked by mudflow materials and, ultimately, entire rivers dry up. The reverse situation may also occur: the river will overflow so much that it will overflow its banks and flood the nearest area, taking lives with it and causing chaos.  Many technological processes are urgently suspended, which is why chemicals are released into the air that poison people. The devastation can also overtake warehouses with dangerous substances, such as weapons, which at best will fail, and at worst, start up and lead to casualties.

Possible forest fires, floods and other consequences that are caused by a single push cannot be ruled out. In order to successfully reduce possible losses during emergencies, there is a complete list of emergency rescue actions: first of all, you need to start searching for victims and evacuate residents, check closed premises for the presence of someone. In the future, you need to spend time on inspection and subsequent first aid to those in need, as they may be under severe stress or injury. After that, the victims should gather in some prearranged point, for example, a shelter, which is always found in cities located in areas with an increased chance of earthquakes. The nearest areas should be evacuated to safer ones, those located as far as possible from the epicenter. After that, the clearing of paths begins, a re-examination of places where there may be people, checking those who have gathered according to the lists of residents, eliminating panic, already full-fledged assistance to victims from specialists and other actions necessary to minimize victims.

Various destructions are not so terrible, because any structure can be rebuilt, and returning life to a person is another matter.

Classes and types of earthquakes

Classes are distributed depending on the strength of seismic shocks, which in turn depend on the epicenter. Even at a time when a person could hardly write, people left notes in the form of cave paintings to warn posterity about what disasters were and how to avoid them. In the 19th century, already quite educated people tried to figure out and come up with a classification that would depend on the impact of a disaster on human life, the landscape and topography of the planet, as well as on the environment. In Switzerland and Italy, the scale of Eurasia (Eurasia-Forel) appeared, the task of which is to divide the vibrations of shocks by intensity. This scale was not used for a very long time, and already in 1902 the Italian Giuseppe Mercalii proposed his own alternative, in which there were no longer ten, but twelve points:

  1. Not very significant earthquakes that are not felt by people.
  2. The inhabitants of the upper floors begin to feel the shaking, but no visible effects occur.
  3. On the lower floors, a closet, a door or a glass of water weakly sways, and the upper floor is already beginning to feel the shaking to the fullest.
  4. Most people on the street, on the lower and upper floors, feel that the house is shaking. People with less sensitive sleep wake up, cracks in wooden furniture are possible on the upper floors, windows tremble.
  5. People outside the building begin to find it difficult to stay on their feet. The inhabitants of the buildings begin to be afraid, because things fall not only on the upper, but also on the lower floors, the building is already shaking much and this can be seen even from the outside. Doors begin to open without human assistance, cracks appear on the windows, liquid from most vessels can pour out, and vessels break.
  6. Many people from this point start to panic, run away from home and save the most necessary things. Animals start screaming as fear seizes them. Books, dishes, even heavy furniture starts to fall. There are cracks on the walls of brick buildings, the plaster is crumbling.
  7. At this level, buildings begin to fully collapse, standing on the street becomes difficult, drivers flee from cars as their vehicles become uncontrollable.
  8. Most of the brick buildings are collapsing, the strongest of them are shaking violently. Tree branches break off, most of the monuments fall.
  9. Reinforced concrete buildings begin to collapse in the same way as brick ones.
  10. Almost all buildings above 3 floors have already collapsed, the rest are shaking and collapsing.
  11. This level is already a fullfledged catastrophe, since many victims appear, people are not able to stand on their feet, asphalt roads collapse at the seams and all infrastructure is collapsed.
  12. Rivers and lakes change their location, the relief and landscape of the area changes beyond recognition. This level was only a few times, but the consequences remain for many centuries, and people, in turn, are not able to eliminate them. Those earthquakes that reach such proportions pose a threat to the whole world.

Earthquake map

Richter Scale Magnitude and Intensity

The Richter scale is a special list of classes of earthquakes that divides them according to magnitude. This classification is based on the study of the very essence, the energy of seismic waves that occur during a disaster. It was proposed in 1935 by the American seismologist Charles Richter, who only put forward the basic principles. Later it was substantiated by another researcher from America, Beno Gutenberg. It was his theoretical justification that was spread throughout the world, but the scale was named in honor of the founder, which is why the classification of earthquakes in magnitudes is called so.

Charles Francis Richter

Its principle lies in the characterization of the energy released during seismic shocks. Purely theoretically, it has no restrictions, but there are some limits for which this energy has not yet reached and is unlikely to come out in the next centuries. Richter took the logarithmic scale as the basis. This comes out that each value indicates that which will be ten times stronger than the previous. Thus, the earthquakes of the sixth magnitude will be 10 times stronger in terms of oscillations than the tremors of the fifth amplitude, although it would seem, the difference in numbers is not at all great.

True magnitude and its power are slightly different concepts. Power or energy is released in the epicenter itself, the focus, after which it increases 30-35 times when the magnitude changes per unit. But magnitude is a dimensionless value, which is considered proportional logarithms. Thus, all waves differ in magnitude and are classified based on the research of two American scientists.

The Richter scale itself looks like this:

  1. Amplitude 2.0 is inherent in inconspicuous incidents, so they are not given special attention.
  2. 4.5 is already a more significant event, earthquakes belonging to this class lead to little destruction.
  3. Next comes 6.0 this is already destruction of a moderate scale, but still not a world-class disaster.
  4. The strongest of all earthquakes are those with an amplitude of 8.5. There were not so many of them throughout history, but each of them left such a big mark that even after thousands of years they are remembered and their consequences are visible.

Starting from this stage, the opinions of scientists are divided, but most of them are confident that earthquakes with a power of more than 9.0. Since everyone knows that each of these incidents is tremors that occur due to the displacement of the lithospheric plates, thanks to the calculations, the researchers came to the conclusion that seismic waves have some limitations that it is hardly possible to pass. But you can never rule out the possibility that these calculations do not coincide with reality, so you should always remember about safety rules, and it’s better to leave the territory where earthquakes often happen. For example, many travelers are afraid to fly to Japan precisely because of the fear of disaster, although its inhabitants are already used to it and most of the not very significant shocks do not even notice.

An earthquake is primarily an integral event, which is felt only near the junction of lithospheric plates, t.e. at a certain point on the globe. But the strength of the wave does not always depend on the source and the epicenter, since the shocks can occur at different heights, due to which the strength can vary slightly.

Actions and rules of conduct during earthquakes

If you are not a permanent resident, but only a tourist or a traveler who has arrived in an area with a high susceptibility to earthquakes, then you should prepare an action plan in advance, inform all your travelers, for example, family members or friends, and also learn how to provide first aid to everyone. Money, a passport, spare batteries, a small first aid kit and a flashlight this is the bare minimum that every person should have with him, and not only in the territory where shocks are possible, but also in any other, because there are many disasters and dangers in our time, and life is one, once again it is better not to risk it. In the car or at least at home, it is also worth having canned food, drinking water for a couple of days. It is better to place the bed as far as possible from windows and glass, as fragments can cause injury. Heavy objects in the first place should be placed on the floor, supporting cabinets and shelves with them. In principle, it is better not to store chemicals at home, since they are dangerous in themselves. When you remember these basic and clear rules, the likelihood of survival increases. You might think that this is too strong a precaution, but in fact it is better to regret later on the nerves and time spent on preparation than to regret that you did not do this if something happens.

If you have been hit by an earthquake, then you should remember about other rules that can save a life. If the lamps sway, objects fall from the walls and the glass breaks, then first of all it is necessary to remain calm, because after the first shocks there are about 30 seconds before the real danger. During this time, you need to take the most necessary items, documents and money, and after a quick walk or a light run, leave the building. Elevators should be forgotten right away, because they will be turned off immediately or they will collapse. You don’t need to run somewhere when you leave the building, but you shouldn’t stand near it either it’s dangerous, at least. See where the most people are, cooperate with them and wait for the rescuers. If you had to stay indoors, then the safest place would be the corner of an internal wall, for example, the one that everyone has in the bedroom. Keep away from heavy furniture and objects that can fall.

After an earthquake, it is worth giving first aid if you have learned it and know what you are doing. Blockages should not be disassembled, only those that do not require special physical investments, because energy also needs to be saved. If possible, turn on the radio on your phone, as this is the easiest way for rescuers to tell where they are and what to do next. No need to argue with those who saved your life if you are not sure that the person is delusional. Even the most prepared people in a stressful situation can make mistakes this is normal. Calmly say this to a person, and he will most likely calm down, because it is their duty to remain calm while everyone is in a panic.

Protection of the population from earthquakes

Each city, which is located in close proximity to the epicenters of earthquakes, has a whole set of rules, laws and lists of what to do and how to ensure maximum safety for residents. All these measures will include an assessment of the consequences of a possible earthquake, a list of people who are unable to take care of themselves in case of emergency, for example, due to illness, as well as training for rescuers. Thanks to the development of technology, we are quite capable of predicting an impending disaster at least 2-3 hours in advance. This time will not be enough to save everything that is, but a banal evacuation and warning of people is already something that can save most lives. Before a disaster, full-fledged groups are formed, the purpose of which is to help those in need, warn people and gather them. The government should always have shelters with provisions and water for several days. Every year, methods for finding people develop, and rescuers become more and more trained. Yes, and technology does not stand still, because only thirty or forty years ago it was not easy to fully predict an impending incident, but just a hundred years ago it was completely impossible.

The strongest earthquakes table

Year Location of the earthquake Strength (points)

The number of victims and other consequences

The most destructive earthquakes in the history of the world

526 Antioch (Middle East) ? 250 thousand. people.
1290 Bohaiwan Bay (Kitiy) ? 100 thousand. people.
1556 Gansu and Shaanxi (China) 7 800 thousand. people.
1730 about. Hokkaido (Japan) ? 137 thousand. people.
1737 Kolkata (India) 7 300 thousand. people.
1897 Assam (India) ? On an area of ​​23 thousand. km2 the relief has changed beyond recognition; probably the largest and strongest earthquake in the history of mankind
1908 Messina (Italy) 8.4 160 thousand. people.
1920 Gansu (China) 8.6 100-180 thousand. people.
1923 yokohama about.Honshu (Japan) 8.3 143 thousand died. people., 200 thousand injured., more than 1 million were left homeless. people. destroyed 575 thousand. buildings in Tokyo and Yokohama.
1927 Nanshan (China) 200 thousand. people.
1948 Ashgabat (Turkmenistan, USSR) 9.0 176 thousand died. people. (80% of the population of the city), the city is destroyed within 20 seconds.
1950 Himalayas (India-China) ten Killed 1.5 thousand. people., in the mountains destruction on an area of ​​20 thousand. km2
1960 Chile eight.3 More than 2 thousand died. people., 3 thousand suffered. people., left homeless about 2 million. human
1970 Chimbote (Peru) 7.8 67 thousand died. people left homeless 600 thousand. people.
1976 Guatemala 7.5 23 thousand died. people., 70 thousand injured. people., more than 1 million were left homeless. people.
1976 Tanshan (China) 8.2 240-755 thousand died. people., 780 thousand injured. people. the most destructive in the 20th century.
1988 Spitak (Armenia, USSR) 7.0 25-55 thousand died. people., 21 cities and 324 villages destroyed
1990 Iran 8.2 More than 40 thousand. people.
1999 G. Izmit(Turkey) 9.0 About 50 thousand. dead, 35 thousand. wounded and 500 thousand. homeless. Material damage of the order of 25-40 billion dollars. The fault was opened over a length of about 110 km and the maximum measured displacement of rocks reached 4.9 m.
2004 Indian Ocean (by. Sumatra, coordinates 3.3° N.w. and 95.8° in.d. ) 9.0 Tsunami caused by offshore earthquake killed 294,743 people.
2005 Bapakot (Pakistan, on the border with India) 7.6 More than 79 thousand died. people., millions of people at the beginning of winter were left without food and shelter

The strongest earthquakes in the history of Eurasia

1949 Mountain Altai 9.0 More than 150 • settlements affected
1957 Muya Range (Transbaikalia) 9-10 Destruction in Chita, Bodaibo and other settlements
1995 G. Neftegorsk (about. Sakhalin) 9.0 2 thousand died. people., the city is almost completely destroyed
2003 Mountain Altai 8.5 More than 1,000 buildings destroyed, hundreds of people left homeless, damage more than 400 million. rub.
2006 Koryaksky district, Olyutorsky district 7.9 Then from 21.04.06 to 25.12.07 recorded another 56 aftershocks with a magnitude of up to 7 points on the Richter scale; 1064 residents of the district were evacuated; 401 buildings damaged in the regional center of Telichiki (5 points). The largest earthquake in Kamchatka in the last 100 years.

Major earthquakes in Eurasia

The largest earthquake in Eurasia so far occurred on May 24, 2013. The outbreak arose under the Sea of ​​Okhotsk, and the amplitude of the disaster reached 8.2. Krasnoyarsk, Moscow and even Tomsk felt hesitation, and those who live in close proximity to the Sea of ​​​​Okhotsk lost their homes altogether. Prior to this event, three more earthquakes occurred during the spring season, the amplitude of which was 5.5, 6.6 and 7.2. They occurred in Tuva, Kamchatka and near the Kuril Islands. According to reports, there were no human casualties, but thousands of families lost their property.

If you go back in time and remember the times of the Soviet Union, then without any problems you can remember the many disasters that took the lives of thousands of people. One of these occurred on December 7, 1988, the amplitude on the Richter scale was 7.2, and the death toll has reached more than 25 thousand people. The city of Spitak was completely destroyed, and in the amount of devastation they felt more than three hundred settlements.

In 1995, on May 27, Neftegorsk was destroyed, located 30 km before the Earthquake of the Earthquake of Magnitite 7.6. More than two thousand people died under the rubble, when the population of the village was only three. It was a tragedy that destroyed more than half of the inhabitants of Neftegorsk. In monetary terms, the damage in only one settlement was estimated in the amount of over 400 billion rubles.

Large earthquakes in the world

The strongest earthquakes in the world occurred several centuries ago, but humanity should remember that this can happen at the present time. Thus, the most powerful is the catastrophe that occurred in Syria in the far of 1202. On Richter’s scale, the amplitude was less than 7.5 points, but at the same time all the islands of the Tyrrhenian Sea and all of Armenia felt the consequences. Ultimately, over a million inhabitants were exterminated during that period. And this is not even connected with the power, but with the duration of seismic waves. We will never know the exact information, since this is described only in the surviving annals. But to this day, the remains of inhabitants and the ruins of cities that do not exist now are found in that territory.

But we must not forget about the catastrophes that were just recently. For example, on the island of Haiti in 2010 there were shocks of such force that more than 220 thousand people died, 300 thousand were injured and became disabled, and more than 850 thousand went missing. Most of them have never been found, so the possibility that they died cannot be ruled out. Despite the fact that this disaster happened more than 12 years ago, the inhabitants of the island are still trying to restore the ruins and need help. This is the second time Haiti has suffered from such powerful tremors, and the first time happened in 1751.

But in truth, the Valdivian earthquake, which occurred on the evening of May 22, 1960 in Chile, is considered the most destructive in history. It is noteworthy that for more than twenty years this disaster was not considered the most destructive, since the local magnitude reached 8.5 on the Richter scale. The epicenter, as the name implies, was located near the city of Valdivia. During the disaster, waves over ten meters high arose, which caused devastation in Hawaii, even though they are located 10 thousand kilometers from the outbreak. The remnants of the waves even reached the Philippines and Japan. About 20% of the entire industrial potential was destroyed in a few minutes, the main earthquake caused a series of less strong shocks throughout the entire state, and also reached others, for example, a small seismic activity also took place on the Tierra del Fuego archipelago, which greatly frightened the inhabitants. The whole planet felt the power of this incident, but those who were in the immediate vicinity of the epicenter were worst of all. Most of the dead, by the way, did not appear because of the earthquake itself, but because of the tsunami that it caused.

The terrible earthquake in Japan on March 11, 2011

Recent cases of earthquakes

Today, technology has reached such a level that there is a full-fledged map of earthquakes, and each of us from our smartphone can watch live on where and when trouble can happen. For the last couple of years, there have been no really significant aftershocks, only small ones that occur almost every day.

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