Reason of Earthquake:-Friends, as we all know that, earthquakes occur from time to time around the world. Due to which there is a lot of waste in parts of the country. But do you know, what earthquakes come from and what are the types of earthquakes? Today we will give you information related to the earthquake, How this earthquake comes, and how many types of waves are formed, due to which we can recognize the earthquake. Before knowing the cause of earthquakes, we will tell you what an earthquake is and what is its loss.
What is an earthquake? and Reason of Earthquake
A sudden stir in the interior of the Earth called an earthquake. In simple words, when the lava in the inner part of the earth becomes very active and starts coming out, but due to some reasons, it does not come out. Due to which the internal parts of the earth begin to stir and the earth starts moving. This condition called earthquakes.
Reason of Earthquake:-
There may be much Reason of Earthquake. One of the reasons for earthquakes is the structure of our earth, so we will tell you different reasons why earthquakes occur on Earth?
1. Earthquake due to Earth’s structure
The structure of our earth is millions of years old when the terrain of our earth was being formed. then many plots were interconnected. Due to which a crack formed between two different plots known as tectonic plates. Tectonic plates are connected to each other in three ways Which are as follows
- Normal faulting:- In normal faulting, The two plots can opposite each other downwards due to which there is a slight change in the upper part of the earth and the ground separated from each other, in this separation the earthquake formed.
- Reverse faulting: –Normal faulting at this stage, The opposite is that of actions, that is the lower surface of the earth rises up causing earthquake on earth.
- Strike-slip faulting: – In this, the plots of the upper surface of the earth move with each other, due to which cracks and earthquakes occur on the earth.
2. Earthquake due to volcano eruption
Earthquakes are also caused by earthquakes in many places across the country. Because when the hot places in the central part of the Earth try to get out the lava but they do not come out completely. Due to which there is a shock in the interior of the Earth, due to this shock, earthquakes occur on the earth.
3. Earthquake due to collapse
Occasionally, landslides in the mines created in the ground create excessive pressure, causing a stir in the upper part of the earth. This movement is known as earthquakes.
4. Using explosives above the outer surface
Earthquakes continue to occur while testing explosive materials made by military forces. This type of earthquake called an artificial earthquake.
There is so many Reason of Earthquake but when an earthquake starts at its centre, it produces three types of waves, which are described below.
- P waves: –These waves also called primary waves of an earthquake. These waves are longitudinal waves like sound waves. Their transmission and movement oscillate in the same direction and these waves cause pressure, they also called pressure waves. Their average speed is 8 kilometres per second, but in high-density rocks, the speed of these waves is 8 to 14 kilometres per second. These waves can pass through all three solids, liquid, and gas.
- S. waves: –They also called second waves or transverse waves of an earthquake. The direction of oscillation in the transmission direction and taxes of these waves are right angles to each other. The average speed of these waves is 4 kilometres per second. These waves can only pass through a solid medium whereas in the swimming medium they cannot pass.
- L waves: – These also known as surface long waves of the earthquake, this wave discovered by HD Love, due to which also called Love waves. These waves mainly confined to the surface and can travel in all three mediums, these waves have a speed of 3 kilometres per second.
The behaviour of seismic waves
- The velocity of all seismic waves increases when passing through high-density materials. while their velocity increases even when passing through low-density materials.
- Increasing the density of rocks in the interior of the Earth increases the velocity of seismic waves.
- The speed of the waves is also about 7 kilometres per second on the ground surface and the speed of these waves is about 5 kilometres per second. while at the depth of 1000 kilometres, the speed of the waves is 11 kilometres per second. And the speed of these waves is 6 kilometres per second.
- Earth has the highest speed of seismic waves at a depth of 2900 km where P waves move at a speed of 13.7 km per second and S waves at a speed of 7.3 km per second.
- Earth’s core starts at a depth of 2900 kilometres. At this depth, the speed of the waves decreases and it decreases to 8.4 kilometres per second. The reason for this is that when they reach the bottom of the core, they become largely reflective.
The magnitude of an earthquake is the measure of the energy released by that earthquake. The amplitude of the seismic waves is based on the phase-frequency and many other mathematical considerations. The magnitude of the earthquake measured on the reactor scale, invented by Charles F. Reactor and Gutenberg.
The intensity and their magnitude
|3.5 to below||Instrumental|
|4.9 – 5.4||Strong|
|5.5 – 6.1||Very Strong|
|7.4- 8.1||Very Disastrous|
|8.1 to Above||Catastrophic|