Wednesday, January 13, 2010

What is an Earthquake??


An earthquake happen when there is a sudden breaking and movement of large sections of tectonic plates which makes the earth shakes of the ground suddenly without early signs. It can occur at any time of the day or night.

For hundreds millions of years, the forces of the tectonic plates which formed a giant crust of the earth's surface moved slowly over, under, past and away from each other. Sometimes its move gradually. The plates continues moving and will meet the edges of the other plates. As both plates touch each other, the movement will still continue until the forces grow strong enough and released, making the plates suddenly break free and causing the ground to shake.

The shocks of earthquake could occur continuously where the smaller earthquake will follow the main shock which cause further damage to weak structures of building as well. It could happen at first hour, days or months after the main shock. But sometimes it could be an early sign of a larger earthquake to happen.

The tectonic plates are also known as the earth's rocky outermost crust. The edges of the tectonic plates are marked by faults or fractures. Most earthquakes occur along the fault lines when the plates slide past each other or collide against each other.

When the plates slides and move away or towards each other, it will send out shock waves that maybe powerful enough to :-
  • open the great cracks in the ground, thrusting up cliffs and can even alter the surface of the Earth
  • cause great damage as the building or bridges collapse, broken power and gas lines, electricity facilities and the telephone service.
  • Sometimes could start fires, landslides, flash floods, snow avalanches, tsunamis and volcanic eruptions.


Fault or fault plane = the surface where when 2 blocks of the earth suddenly slip past one another.

Hypocenter = the location below the earth's surface where the earthquake starts.

Epicenter = the location on the surface of the earth directly above hypocenter.

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