EARTHQUAKE A NATURAL DISASTER

Description

Earthquakes are geologic events, also described as the shaking, vibration, rolling or sudden shock of the earth’s surface, that follows a release of energy in the Earth's crust caused by the sudden dislocation of material within the earth's outer layer, and can be felt over large areas although they usually last less than one minute. Some of them are so slight that they are barely felt and others are so violent that cause extensive damage.

Every earthquake has an epicenter that it is the point on the Earth's surface directly above the focus. The location of an earthquake is commonly described by the geographic position of its epicenter and by its focal depth.

Causes

Earthquakes are caused by stresses below the earth's outer surface. These stresses usually build up until the rocks fracture along a *fault plane. This causes vibrations, also known as *seismic waves and then, they travel in all directions from the area of fracture. In large earthquakes seismic waves may be detected over the entire earth.
Also this phenomenon is caused by a release of energy that can be generated by a sudden dislocation of segments of the crust, by a volcanic eruption, or event by manmade explosions, but until now the most destructive earthquakes are the one’s that are caused by dislocations of the crust.

*A fault is a fracture in the Earth's crust along which two blocks of the crust have slipped with respect to each other.
* Some seismic waves travel through the earth's interior while others travel only over the earth's surface, but there are two types of body waves. The primary wave, is the faster of the two and always travel at higher speeds than the other, so whenever an earthquake occurs, the primary waves are the first to arrive and to be recorded at geophysical research stations worldwide. These waves are transmitted through all parts of the earth. And the other wave, also called shear waves are slower than the primary waves and causes lateral vibrations.

Consequences

Earthquakes produce various damaging effects to the areas they act upon. This includes damage to buildings and in worst cases the loss of human life. The effects of the rumbling produced by earthquakes usually leads to the destruction of structures such as buildings, bridges, dams and also provoke landslides.

We don't have methods for prevention because Earthquakes cannot be predicted but scientists are working on it.