A natural disaster is always a threat because it invariably results in destruction of environment and displacement of people physically and economically. One of the most destructive and feared natural disaster is earthquake. Earthquake can result in tsunamis, drought and diseases.
What is an Earthquake?
Earthquake is the shaking, rolling or sudden shock of the earth’s surface. They are the earth’s natural means of releasing stress. More than a million earthquakes rattle the world each year. Earthquakes can be felt over large areas, although they usually last less than a minute. Earthquakes cannot be predicted, but scientists are working on it.
What Causes Earthquakes?
There are about 20 plates along the surface of the earth that move continuously and slowly past each other. When the plates squeeze or stretch, huge rocks form at their edges and the rock shift with great force, causing an earthquake.
To have a better understanding, think of this kind of experiment. For example, you are holding a pencil horizontally. If you were to apply a force to both ends of the pencil by pushing down on them, you would see the pencil bend. After enough force was applied, the pencil would break in the middle, releasing the stress you have put on it. The earth’s crust acts in the same way. As the plates move they put forces on themselves and each other. When the force is large enough, the crust is forced to break. When the break occurs, the stress is released as energy which moves through the earth in the form of waves, which we feel and call an earthquakes.
What are the effects of Earthquakes?
Earthquakes produce various damaging effects to the areas they act upon. This includes damage to building 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 building, bridges and dams. They can also trigger landslides. Besides producing floods and destroying buildings, earthquakes that take place under the ocean can sometimes cause tsunamis or tidal waves.
