How the earthquake strength is measured
The intensity of the tremors is measured by scores. Earthquakes of 1-2 points are captured only by special instruments - seismographs.
With the strength of the earthquake of 3-4 points, fluctuations already catch not only the seismographs, but also the person - the objects surrounding us, the chandeliers, the pots of flowers, the dishes are ringing, the doors open at the cupboards, the trees and buildings are swaying, and the person himself is rocking.
With 5 points shakes even more, the wall clock stops, buildings appear cracks, and the plaster is showered.
At 6-7 points, fluctuations are strong, objects fall, pictures hanging on the walls, cracks appear on the window panes and on the walls of stone houses.
Earthquakes of 8-9 points lead to a collapse of walls and destruction of buildings and bridges, even stone houses are destroyed, and cracks form on the surface of the earth.
10-point earthquake has more destructive character - buildings are collapsing, there are gusts of pipelines and railway rails, landslides and landslides occur.
But the most disastrous for the strength of destruction are earthquakes of 11-12 points.
In a matter of seconds, the natural landscape is changing, mountains are being destroyed, cities are turning into ruins, huge holes are missing, lakes are disappearing, and new islands may appear in the sea. But the most terrible and irreplaceable in such earthquakes is that people are dying.
There is also another more accurate objective method for estimating the strength of an earthquake - the magnitude of the oscillations caused by an earthquake. This value is called the magnitude and determines the force, i.e. the energy of the earthquake, the highest value of magnitude-9.
Hearth and earthquake epicenter
The destructive force also depends on the depth of the earthquake foci, the deeper the earthquake originates from the earth's surface, the less destructive force is carried by seismic waves.
The outbreak occurs at the site of the displacement of giant rock massifs and can be at any depth from eight to eight hundred kilometers. It does not matter at all whether this displacement is great or not, there are still fluctuations of the earth's surface and how far these fluctuations spread will depend on their energy and strength.
The greater depth of the earthquake focus reduces the damage to the surface of the earth. The destructiveness of an earthquake also depends on the size of the hearth. If the fluctuations of the earth's crust are strong and sharp, then catastrophic destruction takes place on the surface of the Earth.
The epicenter of the earthquake should be considered a point above the hearth located on the surface of the earth. Seismic or shock waves diverge from the hearth in all directions, the farther from the source, the less the intensity of the earthquake. The velocity of shock waves can reach eight kilometers per second.
Where do earthquakes occur most often
What are the corners of our planet that are more earthquake-prone?
There are two belts where earthquakes occur most often. One belt has a beginning near the Sunda Islands, and the end on 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, Caucasus, the Balkans, the Apennines, the Pyrenees and passes through the Atlantic.
The second belt is called the Pacific. It is Japan, Phillippines, it also covers the Hawaiian and Kurile Islands, Kamchatka, Alaska, Iceland. It 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. These are the Northern Caucasus, Altai and Sayans, the Kuril Islands and Kamchatka, Chukotka and the Koryak Highlands, Sakhalin, Primorye and the Amur Region, the Baikal zone.
As often earthquakes occur and our neighbors - in Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, Armenia and other states. And in other areas, which differ in seismic stability, there are periodic tremors from time to time.
The seismic instability of these belts is associated with tectonic processes in the earth's crust. Those territories on which there are operating smoking volcanoes, where there are mountain massifs and the formation of mountains continues, most often earthquake foci are located and in places often there are tremors.
Why earthquakes occur
Earthquakes are a consequence of the tectonic movement occurring in the depth of our Earth, the reasons for which these motions arise are the outer impact of space, the sun, flashes in the sun and magnetic storms.
This, and the so-called, earth waves that periodically appear on the surface of our earth. These waves are well visible on the sea surface - sea tides. On the earth's surface, they are not visible, but fixed by instruments. Earth waves cause deformation of the earth's surface.
Some scientists have suggested that the culprit of earthquakes may be the Moon, more precisely, the fluctuations occurring on the lunar surface, they also affect the earth's surface. It was observed that the strong destructive earthquakes coincided with the full moon.
Scientists also note those natural phenomena that precede earthquakes - they are strong, protracted precipitation, large differences in atmospheric pressure, unusual glow of air, restless behavior of animals, as well as an increase in gases - argon, radon and helium and uranium and fluorine compounds in undergroundwaters.
Our planet continues its geological development, the growth and formation of young mountain massifs occur, new cities appear in connection with human activity, forests are destroyed, swamps are dried up, new reservoirs are created, and those changes that occur in the depth of our Earth and on its surface causeall sorts of natural disasters.
Human activities also have a negative effect on the mobility of the earth's crust. A man who imagines himself to be a tamer and creator of nature, unintelligently interferes with the natural landscape - he is demolishing mountains, erecting dams and hydroelectric stations on the rivers, building new reservoirs and cities.
Yes, and the extraction of minerals - oil, gas, coal, building materials - gravel, sand - affects seismic activity. And in those areas where the probability of earthquakes is high, seismic activity is even greater. By his ill-conceived actions, people provoke landslides, landslides and earthquakes. Earthquakes that arise in connection with human activities are called technogenic .
Another type of earthquake occurs with the participation of a person. In underground nuclear explosions, when tests of tectonic weapons are conducted, or when a large number of explosives are blown up, the earth's crust also oscillates. The intensity of such tremors is not very high, but they can provoke an earthquake. Such earthquakes are called artificial .
Still there are volcanic earthquakes and collapsed .Volcanic earthquakes occur because of the high voltage in the bowels of the volcano, the cause of these earthquakes are volcanic gas and lava. The duration of such earthquakes from several weeks to several months, they are weak and do not pose a danger to people.
Earthquakes are caused by large landslides and landslides.
Earthquakes occur on our Earth every day, about hundred thousand earthquakes a year are fixed by devices. This incomplete list of catastrophic earthquakes that occurred on our planet clearly shows what losses humanity is suffering from earthquakes.
Catastrophic earthquakes that occurred in recent years
1923 - Japan-epicenter near Tokyo, killing about 150 thousand people.
1948-Turkmenistan, completely destroyed Ashgabat, about one hundred thousand dead.
1970 in Peru, a landslide caused by an earthquake ruined the lives of 66 thousand residents of Yungai.
1976god - China, destroyed the city of Tianshan, 250 thousand dead.
1988year - Armenia, the city of Spitak was destroyed - 25 thousand people were killed.
1990god - Iran, the province of Gilan, 40 thousand dead.
1995god - Sakhalin Island, 2 thousand people were killed.
1999 - Turkey, the cities of Istanbul and Izmir - 17 thousand dead.
1999-Taiwan, 2,5 thousand people were killed.
2001year - India, Gujarat-20 thousand dead.
2003 - Iran, the city of Bam was destroyed, about 30 thousand people were killed.
2004-Sumatra-earthquake and tsunami, caused by the earthquake, killed 228 thousand people.
2005 - Pakistan, Kashmir-76 area of thousands of people killed.
2006 - the island of Java-5700 people dead.
2008 - China, Sichuan Province, the dead-87 thousand people.
2010 - Haiti, the deaths of -220 thousand people.
2011 - Japan - an earthquake and tsunami, killed more than 28 thousand people, explosions at the nuclear power plant Fukushima led to an environmental disaster.
Powerful shocks destroy the infrastructure of cities, buildings, depriving us of housing, bring enormous damage to the inhabitants of those countries where the elements took place, but the most terrible and irreplaceable is the death of millions of people. History keeps the memory of the destroyed cities, the disappeared civilizations and whatever terrible force the elements lacked, a person, having survived the tragedy, restores his habitation, builds new cities, erects new gardens and revives the fields on which he grows his living.
How to behave in the event of an earthquake
At the first tremors of an earthquake, a person experiences fear, confusion, because everything is moving around, chandeliers are shaking, dishes are ringing, cabinet doors are opening, and sometimes objects are falling, the ground is running out from under your feet. Many panic, start to rush, others on the contrary linger, freeze in place.
If you are on 1-2 floors, the first thing you should do is try to leave the premises as quickly as possible and move to a safe distance from buildings, try to find an open space, pay attention to power lines, you can not be under them, with strongjerks can break off the wires and you can get an electric shock.
If you are above the 2nd floor or did not manage to jump out into the street, try to leave the corner rooms. It's better to hide under the table or under the bed, stand in the doorway of the inner doors, into the corner of the room, but away from the cabinets and windows, as the broken glass and objects in the closets, and the cabinets themselves, the refrigerators when falling, can hurt you and injure you.
If you still decide to leave the apartment, then be careful not to go into the elevator, in case of strong earthquakes the elevator can disconnect or crash, just do not advise to run to the stairs. Stair flights can be damaged due to an earthquake, and a crowd of people pouring into the stairs will increase the load on them and stairs can collapse. Going out onto balconies is just as dangerous, they can also collapse. You should not jump out of the windows.
If the tremors have caught you on the street, move to the open space, away from buildings, from power lines, from trees.
If you are in the car, stop at the side of the road, away from streetlights, trees, billboards. Do not stop in tunnels, under wires and bridges.
If you live in a seismically active zone, and earthquakes periodically shake your homes, then you must prepare yourself and your family for the possibility of a stronger earthquake. Define the safest zones in your apartment in advance, take measures to strengthen your housing, teach children how to behave, if during the tremors children are at home alone.
An earthquake is a natural phenomenon with destructive power, an unpredictable natural disaster that occurs suddenly and unexpectedly. An earthquake is an earthquake caused by tectonic processes occurring inside the earth, these are earth surface fluctuations that occur as a result of sudden discontinuities and dislocations of parts of the earth's crust. Earthquakes occur anywhere in the world, at any time of the year, determine where and when, and what strength the earthquake will be virtually impossible.
They not only destroy our homes and change the natural landscape, but also demolish cities and destroy entire civilizations, they bring people fear, grief and death.
