Recently we witnessed the sad happenings in Haiti and Chile due to earthquake. Years ago our country India also faced such a tragedy. The states affected in India were Gujarat and Maharashtra. Also we witnessed a tsunami that hit many coastal cities of our country which was originally due to an earthquake in Indonatia. In all these mishaps thousands lost their lives and dwellings. Still many areas are prone to earthquakes.
In India it occurred due to the drifting of so-called Indian plate. Geologists divide earth into many tectonic plates which drift very slowly. These plates slide against each other at some time or move towards each other at some time. During both these process a large quantity of energy is released causing terrible destructions.
Let us look the phenomena in detail. About 225 million years ago the continents in the world were not separated by oceans !! The whole earth was a single continent called Panagea. About 200 million years ago Panagea split into two major continents . One of them was known as Gondwana Land . This Gondwana Land contained Africa, South America , India and Australia. Gondwana Land continued to split and formed small small land masses. Thus the Indian plate also formed. The Indian plate drifted at a speed of 9 meter per century towards Eurasian plate. When the plates met under high pressure the Himalayas formed.
Natural Earthquakes are caused by endogenic forces. There are different types of earthquakes. They are described below.
- Volcanic – This is caused by volcanic eruptions.
- Tectonic – This is caused due to stress and strain along earth’s plates. It may also occur due to dislodging of rocks during faulting.
- Isostatic – This is caused by isostatic imbalance caused by some sudden geological activities.
4. Plutonic – These are earthquakes originating about 250 to 650 kilometers inside earth.