Earthquake is a natural disaster which happens because of the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves.
Most common reason of the earthquake
In the earth crust movement of tectonics plates results in the energy which kept accumulated in the same way as energy builds up in the spring of a watch when it is wound. When the stress finally exceeds the strength of the rock, the rock fractures along a fault, often at a zone of existing weakness within the rock. The stored energy that is suddenly released as an earthquake! Intense vibrations, or seismic waves, spread out from the initial point of rupture, the focus, like ripples on a pond. These waves are what makes the ground shake and can travel large distances in all directions.
When the epicenter of a large earthquake is located offshore, the seabed may be displaced sufficiently to cause a tsunami. Earthquakes can also trigger landslides, and occasionally volcanic activity.
Earthquake intensity is measured with the help of seismometers. It is also known as Richter scale. A magnitude of 3 on Richter scale is indiscernible whereas a magnitude higher than 7 usually causes damage and destruction.
