Occurrence of an Earthquake


 
 
Concept Explanation
 

Occurrence of an Earthquake

How an Earthquake occurs: Earthquake generally occurs at plate boundaries (also called seismic zones or fault zones). Here is a simplified description of how an earthquake happens.

  • The plates rub against each other as they move. Pressure builds up against these rough edges.
  • As the pressure builds up continues, the edges give way. The resulting sudden movement of the plates causes an earthquake. The point where the edges give way is called the focus. The point vertically above the focus on the surface of the earth is called the epicentre.
  • Vibrations caused by an earthquake travel in the form of waves within the earth or along the surface of the earth. These waves are called seismic waves.  Alaska is the most earthquake prone state in the world. It experience a magnitude of 7.0 earthquake every year and a magntiude 8.0 or greater earthquake approximately once every14 years.
  • Sample Questions
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    Question : 1

    Where do most earthquakes occur?

    Right Option : B
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    Question : 2

    The point vertically above the focus on the surface of the earth is called the ____________________.

    Right Option : A
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    Question : 3

    As rupture along a fault initiates, waves of energy travel outward from the hypocenter in a __________________

    Right Option : C
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