"Natural disaster - earthquake"Завантажити презентацію
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Earthquake an is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.
Depending on the cause and location of occurrence, earthquakes are divided into: - tectonic; - volcanic; avalanche; - moretrusy; - Man-made or anthropogenic.
Tectonic earthquakes occur due to the sudden removal of stress, such as the displacement along the fault in the earth's crust (recent studies show that the cause of deep earthquakes may be phase transitions in the mantle, which occur at certain temperatures and pressures).
Volcanic earthquakes result from sudden movements magmatic melt in the ground or in the result of the gap under the influence of these movements.
Man-made earthquakes may be caused by an underground nuclear test, filling reservoirs, oil and gas by pumping fluid into the borehole, blasting in mining and so on.
Cause of earthquakes The cause of the earthquake is the rapid displacement of crust as a whole at the time of plastic (brittle) deformation elastically strained rocks in the earthquake. Most earthquake foci occur near the surface of the Earth. This bias is caused by elastic forces during the discharge process - reducing the amount of elastic deformation in all areas of the plate and the shift to a state of equilibrium.
Characteristics of earthquake Earthquakes taking over large areas and are characterized by: the destruction of the buildings, which fall under the wreckage of people , the emergence of mass of fires and industrial accidents , flooding residential areas and entire regions; gassing during volcanic eruptions , lesions of the people and the destruction of buildings fragments of volcanic rocks , engage people and the occurrence of local fires in settlements from volcanic lava , failure of settlements in landslide earthquakes , destruction and flushing settlements tsunami waves , negative psychological effects.
The consequences of dangerous earthquakes: - Demolition of buildings and structures; - Destruction of potentially hazardous facilities, oil and gas pipelines; The formation of blockages, destruction of life-support systems and breaks the crust.
1) If there are children , you must immediately put them in a safe place , which may be internal doors or openings inside corners of rooms . We must move away away from windows and outside walls, bulky and tall furniture . You can hide under a desk or other sturdy furniture. The greatest danger from above falling objects , stones , beams , etc. 2 ) Remember that you can not run out during an earthquake the house, because the falling debris and destruction of the walls is the main cause of many victims. More chances to save lives , if you will seek salvation where there are. You must wait until the earthquake, then you can leave the building. In no case do not try to get out of the building via the elevator that can get stuck or fall into a pit. 3) If the building in which you are located low and not seismically stable, for example, brick house and have the opportunity to immediately leave it , in this case carefully and quickly leave the building , run off from it at a safe distance. 4) If at the time of the earthquake , you are close to tall buildings , then quickly stand in the doorway to protect yourself from falling debris . 5) If at the time of the earthquake , you 're on a fairly open area , then depart away from power lines .. 6) earthquake pledge you in a car, you need to stay away from tall buildings and other structures and does not start moving to the termination of the earthquake. 7) during an earthquake you were in a boat near the coast and are high-rise buildings and other structures , then try to sail from the coast to protect yourself from falling debris . If on the banks no buildings , we must as soon as possible to get to the shore and away and away from water , because an earthquake can cause a tsunami or strong waves .