Why do earthquakes happen?
New Delhi: Earthquake tremors were felt late night in many parts of the country including Delhi-NCR. The epicenter of the earthquake was in Hindukush in remote Afghanistan. The intensity of the earthquake is said to be 6.5 on the Richter scale. An earthquake of such intensity on the Richter scale is considered very dangerous. Earthquake tremors were felt in many cities of India, Afghanistan and Pakistan. However, there is no news of any damage so far. But after the devastation in Turkey and Syria, people are very much worried about this earthquake. Today in this article, let us know why earthquakes occur and how their intensity is measured and how much damage can be caused by an earthquake.
Earthquake occurs due to collision of plates
This earth is mainly made up of four layers, which are called inner core, outer core, mantle and crust. The crust and the upper mantle are called the lithosphere. These are 50 kilometers thick layers, which are called tectonic plates. These tectonic plates keep on moving from their place, keep on rotating, keep on sliding. These plates usually move about 4-5 mm from their place every year. They can move from their place both horizontally and vertically. In this sequence, sometimes a plate moves closer to another plate and some moves away. During this, sometimes these plates collide with each other. In such a situation, an earthquake occurs and the earth shakes. These plates are about 30-50 km below the surface.
epicenter and intensity
The epicenter of an earthquake is the place just below which the movement of the plates releases geological energy. Earthquake vibrations are felt more at this place. As the frequency of vibration goes away, its effect decreases. Its intensity is measured on the Richter scale. If there is an earthquake of 7 or more intensity on the Richter scale, then the shock is intensified in the surrounding 40 km radius. But it also depends on whether the seismic frequency is on the uptrend or downtrend. If the frequency of vibration is higher then the area of influence is less. The deeper the earthquake goes, the less its intensity is felt on the surface.
What is Richter scale?
The Richter scale is used to measure the intensity of an earthquake. It is also called the Richter Magnitude Test Scale. Earthquake waves are measured on the Richter scale from 1 to 9. The Richter scale was invented in 1935 by Charles Richter, a scientist working at the California Institute of Technology, in collaboration with Beno Gutenberg. The magnitude of an earthquake on the Richter scale can be gauged from the fact that an earthquake on the 8 Richter scale can generate energy released from 6 million tonnes of explosives.
What is the relation between Richter scale and intensity of earthquake?
- When an earthquake occurs on the 0 to 1.9 Richter scale, it is known only by seismograph.
- Mild tremors occur when an earthquake occurs on the 2 to 2.9 Richter scale.
- When an earthquake on the 3 to 3.9 Richter scale occurs, it is as if a truck passes near you.
- An earthquake of 4 to 4.9 on the Richter scale can shatter windows. Frames hanging on walls can fall.
- Furniture can move when an earthquake occurs on the 5 to 5.9 Richter scale.
- The foundations of buildings can crack when an earthquake occurs on the 6 to 6.9 Richter scale. There may be damage to the upper floors.
- Buildings collapse when an earthquake occurs on the 7 to 7.9 Richter scale. Pipes burst inside the ground.
- When earthquakes occur on the 8 to 8.9 Richter scale, large bridges including buildings also collapse.
- Complete devastation when an earthquake occurs on the Richter scale of 9 and above. If someone is standing in the ground, he will see the earth swaying. Tsunami if the sea is near. In an earthquake, each scale of the Richter scale is 10 times more powerful than the previous scale.