What Causes Tsunamis
This Earthquake article is for those people who often wonder about the definition of Earthquakes. In other words “What is an Earthquake”? “How do Earthquakes happen”? and What causes Earthquakes?
School going kids, after reading this guide, would easily understand the causes of Earthquakes.
An earthquake is a sudden offset of earth’s crust , which results in breakage of rocks and intense vibrations, ripping through in all directions.
These immense land jerks, if of high magnitude, weakens the infrastructural pillars of the cities, resulting in loss of human life.
What happens is earth, unlike the moon, is composed of active tectonic plates- which either moves relative to each other or collide against the other- generating tremendous frictional force in the process. A boundary where two tectonic plates meets, also called fault, is the place where 99% of the world’s earth quakes occur.
There are 3 causes of earthquakes.
. Divergent boundary movement
. Convergent boundary movement
. Transform margins movement
Divergent boundary Earthquakes occur when two plates pulls apart, such that there is a depression created on the impact side, often resulting in volcanic magma flowing out of it.
An example of such a scenario is the Arabian, African continental plates, which have been gradually pulling apart from each other for thousands of years, resulting in a depression which is now known as the red sea. The fault lies below the red sea, which is the source of divergent boundary earthquakes in that area.
Convergent boundary system, also called subduction zone, is further divided into 3 cases
. Continent to ocean convergence
. Ocean to ocean convergence
. Continent to continent convergence
In the first case, oceanic plate being denser than the continental one moves down the latter. This subduction process is not a smooth going, rather a frictious one, resulting in Earthquakes.
This phenomena can be observed in north west America, where Juan de fuca, an oceanic plate has been being subducted by the north American continental plate.
In the 2nd case, out of the two oceanic plate, the one which is more buoyant moves below the other .
The 3rd continent to continent phenomena is the roughest earth plate movements of all. Both the plates being hard damn rocks, instead of subducting, build upon one another, growing in size, turning up into gigantic mountainous chains.