Earthquake

‘The earthlings were probably seated comfortably on their couch, maybe sipping their morning brew, or reading the day’s chronicle, while in another pole of the earth some were hitting their bed after a long day’s work, this is when the earth thought to quake!’ In our life, every single one of us has undeniably experienced earthquakes. The earth’s tremor makes us alarm instantly. We rush to find the safe spot thus, honestly, we are terrified of the shakes. 

Have you ever wondered what causes earthquakes? Or more simply put, what exactly is an earthquake? In this context, we are going to discuss precisely this trembler known as an earthquake. 

What is an Earthquake? 

An earthquake can be defined as the sudden movement or the trembling that is felt on the Earth's tectonic plates, this creates a shake or vibration on the ground. This shaking caused by the earthquake can destroy the buildings and in worst cases can even break the Earth's surface. While sudden shakes underwater are known as tsunamis.

Earthquakes are caused by the disturbances in the balance of the earth. Earthquakes are also caused by the reactions which result from the invisible events that operate beneath the Earth's surface known as the earth’s crust. 

What Causes Earthquakes?

In the study of social sciences, we previously have learned the chapter on earth’s crust. So, the layers of the earth are known as: 

1. the inner core

2. the outer core

3. mantle 

4. crust

We know that the crust and the top layer of the mantle are made up of thin skin which is layered on the surface of our planet earth.But, do you know the earth’s skin is not all a single piece? Rather, the skin is made up of many earthly pieces which give the structure like a puzzle. This puzzle-like piece covers the surface of the earth.Another amazing fact is these pieces of the puzzle keep on moving slowly moving around one another, it slides past one another and go on bumping into themselves. In geographic terms, these puzzle pieces are called the tectonic plates, and the edges of the plates are known as the plate boundaries. The plate boundaries are created by many faults, and most of the earthquakes around the world occur on these faults themselves. 

How Does an Earthquake Occur?

The edges of these plates are quite rough, thus while bumping into each other, the edges get stuck while the rest of the plate keeps on moving. Finally, when the plate has moved quite far enough, the edges then create a vibrating motion and unstick on one of the faults, and then there causes an earthquake.

Effects of Earthquake:

Every phenomenon on this earth has a cause and effect. In the previous section we have studied the cause of the earthquake, now in this section, we will know about the effects of earthquakes.

1 Ground Shaking                

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Ground shaking is the most common effect that happens during an earthquake. In fact, this is the first effect that indicates an occurrence of an earthquake. The shaking of the ground is a result of the passage of the seismic tremor which is caused through the ground. The seismic waves range from gentler type small earthquakes to incredibly violent or large earthquakes. 

2 Ground Rupture

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Ground rupture is another destructive effect of earthquakes that is caused when due to the shakings of the earthquake a fault actually breaks the Earth's upper surface. Though this incident of ground rupture for an earthquake is comparatively very rare, there have been cases of it in most of the parts of California.

3 Landslides

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Landslides can also be caused due to earthquakes. Landslides happen both by the direct rupture and by the sustained shaking of the unstable slopes. These dangerous slides can easily destroy any buildings which come in their path. They also block roads, railroad lines, or take the hilltop homes down. 

4 Tsunamis

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Tsunamis worldwide proved to be a grave hazard, particularly around the Pacific Ocean region. Tsunamis are actually a series of water waves that are caused when the seafloor makes movement vertically in times of an earthquake.

5 Fires

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Fires are another horrific effect that causes huge damage after the earthquakes. The ground rupture and liquefaction caused due to earthquakes can easily emit out the natural gas mains and the water mains, these both contribute to the ignition of fires which hinders the efforts to control them effectively. 

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In the year 1994, Northridge faced an earthquake where water was pouring down the streets from broken water channels while at the same spot, and at the same time, the fire was blowing out of the ruptured channels.

Types of Earthquakes

The types of earthquakes majorly depend upon the region where it occurs and the geological structure of that region is also defined here. There are many different types of earthquakes, most basic and popular are these types:

• Tectonic Earthquake

• Volcanic Earthquake

• Explosion Earthquake

Among these, the most common types of earthquakes are the tectonic type earthquakes which occur when the rocks in the earth's crust break because of the geological forces that are created by the motion of the tectonic plates.

The Volcanic types of earthquakes occur with a combination of volcanic activity. Among these is the collapse of earthquakes, which happen in underground caverns or mines.

Explosion earthquakes have resulted from the explosion of any nuclear or chemical devices. 

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Earthquakes are being recorded by an instrument called seismographs. While the intensity of earthquakes is measured by the Richter Scale. 

How Does a Seismograph Work?

The seismograph has a definite base structure that is being placed firmly in the ground, and then a heavy weight-like structure is hung freely. When an earthquake causes the ground to shake naturally, thus the base of the seismograph shakes in that effect, but the hanging heavyweight due to its load does not move. Instead, the spring or the string that is kept hanging from the weight absorbs all the movement. The difference in the position which is between the shaking part of the seismograph and the motionless part is then recorded on a white sheet of paper.

Magnitude of Earthquake

Here are some effects of earthquakes according to different magnitudes. 

Magnitude                     Earthquake Effects

6.1 to 6.9          -        Might cause a lot of damage in populated areas.

7.0 to 7.9          -        This is a major earthquake with serious damage. 

8.0 or more      -        Can destroy the whole community near the epicenter. 

Did You Know?

• Can scientists really predict earthquakes?

Absolutely not, and it seems that they can never predict them. They have tried a lot of ways to predict the earthquake but for one fault or the other, the procedure did not succeed. 

• Can really some animals or any mystic people tell when an earthquake is about to hit the earth?

The answer can never be a definite one. It is difficult for us to say whether some animals or people can actually predict an incoming earthquake.

• Earthquakes are not Evil!

This is a fact that earthquakes never killed anyone. Rather this is the fault of our constructed weak and tall buildings which cannot bear the shakes. We have to understand, earthquakes are mindless and natural occurrences, we human beings are not the same!

Thus, we are now completely educated about earthquakes, why they happen, how they happen, and what their types are. Earthquakes are a natural phenomenon that causes different earthy structures. It erupts on its own and calms down on its own. All we need to make sure of is taking all the precautions while it hits.