What Causes Earthquakes?
by Nithya[ Edit ] 2010-02-11 09:48:59
When the earth shakes due to the movements of plates below the earthâs crust it is known as Earthquake. Earthquakes are natural disasters, which kill thousands of people in an instant and can destroy cities and countries- human habitation across miles. The vibration during an earthquake has the potential to wreak havoc and destruction, which is beyond imagination. The destruction is the maximum near the epicenter, the place from where the vibrations arise and spread. Of late there have been many such natural disasters, which can be associated with earthquakes like the Tsunami that hit the shores of India, Thailand and razed down buildings and annihilated many lives. It seemed like Mother Nature was avenging herself on us who have used all her endowments to the fullest extent without caring to rejuvenate them. Here we would try to find out the causes of earthquakes so that we can all contribute to the prevention of such things in our own small ways. Individual awareness would definitely lead to mass awareness.
Causes of earthquakes
If seen broadly we can say that earthquakes are caused due to two major reasons. The first reason is the eruption of volcanoes, which are sudden, and as is known volcanoes are seat of inner disturbance and can effect the plates which is the second cause of earthquakes. Earthquakes are caused due to disturbance in the movement of plates, which again can be caused due to various reasons like under crust waves or cracks in the plates.
Plate Tectonic Theory
The outer layer of the earth is divided into many sections known as plates, which are floating on the molten magma beneath the earthâs crust. Now the movement of these plates is determined by the convection current in the molten magma. The heat makes these plates rise and vice versa. Therefore after intervals there are plates that get submerged in the molten magma and there plates that rise upwards and at times even new crust is formed from the molten magma which in turn forms a new plate until it connects itself with the already existing ones. At times these plates and can be pushed up to form mountains and hills and the movement is so slow that it is really hard to comprehend that there is any movement at all. The movement and the results come out to be visible suddenly. Now these plates are the bases on which the continents stand and when these plates move the continents also move. Most of the earthquakes occur on the edges of the plates where a plate is under one or across. This movement disrupts the balance and position of all plates, which leads to tremors, which are called earthquakes.
Volcanic Eruptions
When volcanoes erupt it is because the molten magma under the crust of the earth is under enormous pressure and to release that pressure it looks for an opening and exerts pressure on the earthâs crust and the plate in turn. A place, which is the seat of an active volcano, is often prone to earthquakes as well because the pressure that is exerted by the magma exceeds the limit these plates move and that causes earthquakes. Earthquakes are also caused after a volcanic eruption since the eruption also leads to a disturbance in the position of plates, which either move further or resettle and can result into severe or light tremors.
The excessive exploitation of earthâs resources for our own benefits like building dams to store large volumes of water and blasting rocks and mountains to build bridges and roads is also the reason behind such natural disruptions.
