Earthquakes .Why do earthquakes occur ?

earthquake - a natural phenomenon, possessing destructive force, is an unpredictable natural disaster that occurs suddenly and unexpectedly.The earthquake is the tremors caused by tectonic processes occurring inside the Earth, this oscillation the earth's surface, which arise as a result of sudden ruptures and displacement of the earth's crust.Earthquakes occur at any point on the globe, at any time of the year, to determine when and where, and what kind of force would be an earthquake virtually impossible.

They not only destroy our homes and changing the natural landscape, but also to communicate with Earth face of the city and destroy entire civilizations, they bring people to fear, sorrow, and death.

How to measure the power of an earthquake

intensity of the tremors measured points.An earthquake measuring 1-2 points are captured only by special devices - seismographs.

at force 3-4 points earthquake vibrations already capture not only seismographs, but also a man - swinging objects that surro

und us, chandeliers, pots with flowers, rings crockery, open the door from the cabinet, swaying trees and buildings, and the man himselfrocking.

With 5 points shakes harder, stop clocks on buildings, cracks, crumbling plaster.

When 6-7 strong vibrations, falling objects, paintings hanging on the walls, window glasses and walls of stone houses there are cracks.

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

10-magnitude earthquake has a destructive character - collapsing buildings, come gusts of pipelines and railway tracks, there are landslides and avalanches.

But the most catastrophic damage on the strength of the earthquake are at 11-12 points.
Within seconds, changing the natural landscape, the mountains are destroyed, the city turned into ruins in the land produced large gaps, disappearing lakes and new islands may emerge in the sea.But the most terrible and irreplaceable in such earthquakes - is that people are dying.

There is also another, more accurate method for objective evaluation of earthquake forces - largest fluctuations caused by the earthquake.This value is called the magnitude and determines the strength, that is, the energy of the earthquake, the highest value of the magnitude-9.

Hearth and epicenter

strength of destruction depends on the depth of the earthquake source, the deeper from the surface of the earth there is the earthquake source, the less destructive power carry the seismic wave.

Hearth occurs in the place of displacement gigantic rock massifs and can be at any depth from eight to eight kilometers.It is not important, it is a large displacement or not, there are still fluctuations in the earth's surface and how far spread these variations - depends on their energy and effort.

Large depth of the earthquake source reduces the destruction of the earth's surface.The devastating earthquake also depends on the size of the fire.If fluctuations in the Earth's crust strong and sharp, then catastrophic failure occur on the surface of the Earth.

epicenter of the earthquake should be considered a point above the center, located on the surface of the earth.Seismic and shock waves radiate from the focus in all directions, the farther away from the source, the lower the intensity of the earthquake.The speed of the shock waves can be up to eight kilometers per second.

where most earthquakes occur

What parts of our planet are more earthquake-prone?

There are two zones, where most earthquakes occur.One zone has a beginning at the Sunda Islands, and at the end of the Isthmus of Panama.This Mediterranean zone - it stretches from east to west, passes through the mountains, such kak Himalayas, Tibet, Altai, Pamir, Caucasus, Balkans, Apennines, the Pyrenees and extends across the Atlantic.

second zone called the Pacific.It - Japan, Fillippiny, as it covers the Hawaiian and the Kuril 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.

On the territory of our country as there are seismically active zones.This North Caucasus, Altai and Sayan Mountains, the Kuril Islands and Kamchatka, Chukotka and Koryak Highlands, Sakhalin, Primorye and the Amur region, the Baikal area.

So often there are earthquakes and our neighbors - Kazakhstan, Kyrgyzstan, Tajikistan, Uzbekistan, Armenia and other countries.And in other areas, which are different seismic resistance, periodically there are tremors.

seismic instability of these zones is associated with tectonic processes in the earth's crust.Those areas in which there are acting smoldering volcanoes, where there are mountains and the formation of the mountains, there is most often located in the centers of earthquake locations are frequent tremors.

Why earthquakes

Earthquakes are the result of tectonic movement going on in the depths of our earth, the causes that give rise to these movements are many - is the external action of the cosmos, the sun, solar flares and magnetic storms.

That, and the so-called terrestrial waves that periodically appear on the surface of our earth.These waves are clearly visible on the surface of the sea - tides.they are not visible on the surface, but are fixed devices.Terrestrial waves cause the deformation of the earth's surface.

Some scientists have suggested that the earthquake may be the culprit moon, or rather fluctuations occurring on the lunar surface, they have an impact on the Earth's surface.It has been observed that strong destructive earthquakes coincided with the full moon.

As the researchers note those natural phenomena that precede earthquakes - a strong, prolonged rainfall, large fluctuations of atmospheric pressure, air unusual glow, restless behavior of the animals, as well as an increase in -argona gas, radon and helium and compoundsuranium and fluorine in groundwater.

Our planet continues its geological development, growth and the formation of the young mountain ranges, due to human activities, new cities, forests are destroyed, drained swamps, new reservoirs, and the changes that occur in the depth of our earth and itssurfaces cause all sorts of natural disasters.

Human activity also has a negative impact on the mobility of the Earth's crust.The man who imagines himself a handler and creator of nature, recklessly interferes with the natural landscape - the mountain blows, builds on the rivers and hydroelectric dams, building new reservoirs, city.

Yes and mining - oil, gas, coal, construction materials - gravel, sand - affect the seismic activity.And in those areas where the probability of earthquakes, seismic activity even more amplified.His ill-considered actions of a person provokes landslides, avalanches and earthquakes.Earthquakes that occur due to human activities are called anthropogenic .

Another type of earthquake occurs with the participation of the person.When underground nuclear explosions, whenever conducted tests tectonic weapons, or the explosion of a large number of explosives, as well occur fluctuations in the Earth's crust.The intensity of these shocks is not very large, but they can trigger an earthquake.Such earthquakes are called artificial .More

are volcanic earthquakes and landslip .Volcanic earthquakes occur due to high voltage in the bowels of the volcano, the cause of these earthquakes are volcanic gas and lava.The duration of these earthquakes from a few weeks to a few months, they are weak and are not dangerous for humans.
landslide earthquake caused major landslides and avalanches.

On our Earth earthquakes occur every day, about a hundred thousand earthquakes a year are fixed devices.This is a partial list of catastrophic earthquakes have occurred on our planet clearly shows which losses were sustained by mankind from earthquakes.

catastrophic earthquake that occurred in recent years

1923 - Japan-epicenter near Tokyo, killing about 150 thousand people.
1948, Turkmenistan, Ashgabat completely destroyed, about one hundred thousand dead.
1970 in Peru, a landslide caused by an earthquake destroyed the life 66 thousand residents of Yungay.
1976god - China, destroyed the city Tyanshan 250 thousand dead.

1988god - Armenia, destroyed the city of Spitak -25 000 people were killed.
1990goda - Iran, Gilan province, 40 thousand dead.
, 1995 - Sakhalin Island, 2000 people were killed.
1999 - Turkey, the city of Istanbul and Izmir, 17 thousand victims.

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

2005 - Pakistan, Kashmir region, 76 thousand people dead.
2006 - the island of Java, 5,700 people perished.
2008 - China, Sichuan Province killed -87,000 people.

2010 - Haiti, -220,000 people were killed.
2011-Japan - the earthquake and tsunami that killed more than 28 thousand people, explosions at the Fukushima nuclear power plant led to an environmental disaster.

powerful shocks destroy the infrastructure of cities, buildings, housing depriving us bring enormous damage to the inhabitants of those countries where the element played out, but the most terrible and irreplaceable - it is the death of millions of people.History preserves the memory of the destroyed cities, lost civilizations and whatever terrible force did not have the elements, people, survivors, restore their housing, building new cities, is building new gardens and revives the fields that grow their own food.

How to behave during an earthquake

When the first shock of the earthquake a person experiences fear, confusion, because everything around is in motion, swinging chandeliers, rings crockery, open the door cabinets, and sometimes falling objects land leaves- under the feet.Many panic, start to rush, others on the contrary have been slow, freeze in place.

If you are on floors 1-2, the first thing you should do - is to try as much as possible to leave the premises quickly and move to a safe distance from buildings, try to find an open space, pay attention to the power lines, can not be under them whenstrong shocks may break the wires and you can get an electric shock.

If you are above the 2nd floor and did not have time to jump out on the street, try to leave the corner of the room.It is better to hide under the table or under the bed, get up in the doorway of internal doors in the corner of the room, but away from the cabinets and windows, as the burst windows and objects in the cabinets, and do cabinets, refrigerators in the fall may have hurt and injure.

If you do decide to leave the apartment, be careful not to go in the elevator, the elevator during strong earthquakes may trip or fall, just not advised to run to the stairs.Stairways can be damaged due to the quake, and a crowd of people rushed to the stairs, to increase the load on them, and stairs can collapse.Exit to the balcony just as dangerous as they can collapse.Do not jump from the windows.

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

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

If you live in a seismically active zone, and earthquakes are periodically shaken by your home, then you have to prepare yourself and your family to the possibility of a strong earthquake.Determine in advance the safest areas in your apartment, take to strengthen their own housing arrangements, and teach children how to behave, if during aftershocks children are home alone.