Earthquakes can be human-made or natural. These earthquakes are not random; rather they are the effect of different changes occurring in earth’s crust for a long time.
1. Volcanic Eruptions.
The main cause of an earthquake happening is volcanic eruptions. When boiling lava tries to break through the surface of the earth, with the increased pressure of gases, certain movements are caused in earth’s crust. Movement of lava beneath the surface of the earth can also cause certain disruptions. This sends shock waves through the earth, causing damage. These earthquakes are mild.
2. Tectonic Movements.
The crust is lots of big pieces of rock , comprising of the upper mantle. These plates are always moving, effecting earth’s crust. These movements are categorised into three types: constructive, destructive and conservative. Constructive is when two plates move away from each other. When two plates move towards each other and collide, this is known as destructive plate boundaries. Conservative corresponds to passing by of plates of crust. Earthquakes of this type have varying intensities.
3. Geological Faults.
A geological fault is known as the displacement of plates of their original plane. The plane can be horizontal or vertical. These planes are not formed suddenly but slowly develop over a long period. The movement of rocks along these planes brings about tectonic earthquakes. These faults occur due to the impact of geological forces. The displacement of plates creates the breaking of rocks, which releases a lot of energy.
4. Man Made.
The interference of man with nature can also become a cause of the earthquake. The disturbance of crustal balance due to heavy clubbing of water in dams can cause earthquakes. Nuclear bombing can send specific type of shock waves throughout the surface of the earth, which can disturb the natural alignment of tectonic plates. Mining can also cause disturbance due to the extensive removal of rocks from different areas.
5. Minor Causes.
Some minor causes such as landslides, avalanches, the collapse of heavy rocks, etc. can also cause minor shock waves. The gases beneath the surface of earth contract and expand, giving rise to movements in plates beneath the crust. The plutonic earthquake occurs because of adjustments in rock beds in the interior of earth’s crust. All these factors, correspond to minor earthquakes but sometimes these can also vary to moderate earthquakes.
Emily Henderson @ ELIS 