Taatari crust from time to time movements of vibration , felt by people and sometimes recorded continuously observatories , known as earthquakes or earthquakes and tremors come in the form of horizontal or vertical or windlass , affecting Earth's surface and sometimes cause disasters . Has been known since ancient earthquakes and have had different interpretations are not based to scientific data only after the establishment of the first global association of earthquakes in Japan feature of 1880.
The reason behind the occurrence of earthquakes due to the instability of the earth's crust in some areas where exposed to large subsidence or twists in the rock layers . It is known that many underground forces , in esoteric or magma in the earth's crust , press the multi- layered and Chdha in one direction or another , even if separated from these layers led to the occurrence of earthquakes. This also leads to high separation section of classes in the fall or vertical movement occurs laterally pressure on adjacent layers and lead to vibrations in the transverse waves spread across the globe.
It also may result from earthquakes eclipsed happening in the earth's crust meltdown spaces large caves in the country or the collapse of the limestone layers in salt water due to leakage or young , but their influence is very limited.
The earthquakes on three types : horizontal with a certain direction in which the earth shaking sideways , and vertical vibrating vertically and a windlass earthquakes in each direction where the vibrations spin around itself . And most often occurs in the earthquake point of land is called deep center surface and form a distribution point tremors that are spread in the cortex . May also occur at the center of a deep earthquake of up to 800 km waves spread it to the surface after it is distributed in the earth's crust . But studies conducted so far in the earth's crust does not exceed a depth of 32 km.
Recorded earthquakes , duration and strength and direction on a special machine called a spectrograph earthquakes, this machine be of two types: vertical , horizontal, tremors recorded . The Observatory captures three types of seismic waves caused by the earthquake : observatories, first, and second primaries second wave observatories recorded after the interruption of the first , third, long wave . And pass Almujtan first and second in the ground and spread in the third layer near the earth's crust and limit the time between primaries and capture the wave of the long distance between the Wave Observatory and the epicenter of the quake in the circle represents rays that distance . And so that we can determine the epicenter, more accurately , we need always to the three observatories, each of which determines the distance from the epicenter. This distance represents the beam circuit that can be earthquake has occurred and where the confluence of three circles defines the epicenter.
However, after twenty years of monitoring earthquakes and places of occurrence, it was possible to identify the most unstable regions in the world and put it to a private maps . It seems that earthquakes abound in unstable regions of the Earth's surface where abound Walt nuts and twists and mountains modern configuration , including:
• circle around the Pacific Ocean stretching from the eastern coast of Japan to the Kuril Islands to Alaska , and then to the west coast of the American continent Vhoati west of the American continent Vhoati Vdzr New Zealand , Indonesia , the Philippines, Japan .
• an area stretching from Japan in the east to west across the middle of China and India Heights adjacent geological time , which ends the third Northern Portugal and North Africa region includes .
• Alanadami groove which begins in East Africa and Anyha in the Taurus Mountains of northern Syria .
Finally, we note that the structure of the country Almaúdah deep horizontal layers a few earthquakes in total.
And earthquakes occur at sea , also spoke on land. Fiqiaan seas are exposed to earthquakes as exposed land , which occur , often as a result of subsidence large section of the bottom of the ocean and this sometimes leads to the disappearance of some of the islands . The fit with the severity of earthquakes decline beaches and the presence of deep water drilling .
The cause of the earthquake disaster zones and the continental coastal cities , when they are free because they affect the sea and makes them vibrate and form the high waves of 30 meters in height and know these waves (b ( tidal surge ) ) , in Ottunami in Japan .
Finally, the question has to be : Is the earthquake cycle a certain time ?
In fact did not take long to record earthquakes and this is what gives us a clear idea of whether there is a regular cycle of earthquakes . Powerful earthquakes that have been recorded so far irregular , but 1906 is the year of disasters as the record where the largest number of strong earthquakes , including the San Francisco earthquake and the earthquake in the border between Bolivia and Peru , one of the largest earthquakes. The years pass without a strong earthquake that registered one .