Answers

2016-03-01T16:21:38+05:30

Earthquake is a natural calamity can occur anytime and anywhere on the earth surface, cause lots of disturbance of to the living beings and useful natural resources. If we think about the earthquake, we also think that nothing is more destructive than this natural calamity. Earthquake has its long devastating history from the ancient time all over the world however its monotonous regularity makes us more fearful. Earth crust consists of several unfixed solid rock faces which move slowly below the surface under the range of millimeters to kilometers. The rate of movement increases with the thickness of plates. Such huge moving plates get separated from other plates and get out of their boundaries. Earthquake occurs when such moving plates clash with each other and separate.

Sometimes volcanos (located around edges of the Pacific Ocean, known as Ring of Fire) bursts and releases lots of lava, gas, etc which causes pressure and imbalance within the earth surface and produces earthquake waves in the surrounding areas. Thus, volcanic activity within the earth surface is one of the reasons for earthquakes. Faults created by the volcanic activitiy are filled up by the strong earht surface movement which causes tremor. Everyone should take care of them when earthquake occurs by following some precautions like:

People should stay calm and stay inside or outside the door but away from windows, buildings and power lines. They should stand against the wall near to the center of building, at doorway and crawl under some heavy furnitures like a desk or table. Never use flammable things like matches, candles, or any other flame as they caught fire with broken gas lines. Never use elevators as they may stuck. If someone is in the running car, he/she must stop the car and stay inside until the earthquake stops.

 

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2016-03-01T16:39:27+05:30
An earthquake is the shaking of the earth caused by pieces of the crust of the Earth that suddenly shift. The crust, the thin outer layer, is mostly cold and brittle rock compared to the hot rock deeper inside. This crust is full of large and small cracks called faults. Although these faults can be hundreds of miles long, usually you cannot see the cracks because they are buried deep under­ground and because the pieces of crust are compressed together very tightly.
Earthquakes occur because of a sudden release of stored energy. This energy has built up over long periods of time as a result of tectonic forces within the earth.

Most earthquakes take place along faults in the upper 25 miles of the earth’s surface when one side rapidly moves relative to the other side of the fault. This sudden motion causes shock waves (seismic waves) to radiate from their point of origin called the focus and travel through the earth.
Effects of Earthquakes:

Ground Shaking:

Violent ground shaking could last for up to a minute in a large earthquake. It may be very difficult to remain standing during the earthquake. Several hun­dred aftershocks could be felt in the weeks following the main quake.

Slope Failure (landslides):

Damage from earthquake-induced landslides can range from severely weak­ened foundations and structural failures, to total destruction.

Liquefaction:

Ground-shaking causes some soils to behave like a liquid, causing structures to sink, tilt or topple over.

Fault Movement:

A rupture of the fault could involve horizontal and/or vertical movement of sev­eral metres. This could cause buildings, roads, water mains, gas lines and power cables that cross the fault line to be displaced.


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