Why does an earthquake happen and what exactly is an earthquake

Earthquakes are caused by the release of energy that generates waves that travel in all directions causing the shaking of Earth’s surface.

What exactly is this energy What are the waves What’s shaking of Earth’s surface

This is so complicated well calm down let me explain everything in a simple and detailed manner. Earth is not just one piece it is made up of jigsaw puzzles of around 19 to 20 pieces.

Earth Plates

Which are called tectonic plates these plates are placed on a hot partially molten layer of Earth’s mantle. All our planet’s crust is made up of about 12 major tectonic plates that fit together like a giant jigsaw puzzle these huge slabs of land float on superheated magma and constantly shift bump and grind against one another it’s there along the seams where earthquakes tend to happen when friction between the two plates is violent enough.

These plates move around one to ten centimeters each year but don’t worry not all these movements can be felt by us sometimes these movements are extremely strong and can be felt like a lot of vibrations under your feet or it can also destroy an entire city that’s called an earthquake.

The earthquakes occur in the lithosphere region (The lithosphere is the solid, outer part of the Earth. It includes the brittle upper portion of the mantle and the crust of the earth) an earthquake generates underneath the earth and this releases the energy across the point at which the earthquake occurs.

Under the earth is called hypocenter in the exact place above it and the surface of the earth is called epicenter the most horrifying earthquake recorded till date was of magnitude nine points five out of ten this happened in Valdivia in southern Chile in 1960 another one that happened in Japan into hookah region was of a magnitude of 9.0 which happened on March 11th, 2011 this earthquake caused massive and enormous damage and destruction and took nearly sixteen thousand people’s life with him.

Geologists use a device that can sense the waves created by the movement of the tectonic plates these waves are known as seismic waves and the device is called a seismograph the earthquake events are scaled according to the magnitude of the shock and are known as the Richter scale this magnitude relates to the energy released during the earthquake magnitude is expressed in absolute numbers zero to ten where zero is lowest where people feel nothing and ten being the highest that can create severe destruction and loss of life over a large. In order to know more about earthquake let’s jump to the Inner Core, Mantle Layer, and Earth Crust

Inner Core

As the name suggests, it is the innermost layer or the central layer of oat it is like a solid spherical ball in nature with a Radius of 1250 km, the temperature of Earth’s core ranges between 4,500 to 5,500 degrees Celsius, facing the pressure of 300 to 360 Giga Pascal’s. Next is the outer core it is of about 2200 kilometer thickness and has a temperature similar to the inner core that is off 4500 to 5,500 degrees Celsius.

Mantle Layer

Then we have the mantle layer which is the semi-solid state of about 2900 kilometer thickness this layer makes around 84 percent of Earth’s total volume.


The last layer is the crust which is like apple skin when compared to the other layers. It runs from 0 to 70 kilometers in thickness which is specifically 8 kilometers undersea to 32 kilometers under continents and this is only 1% of the Earth’s total mass.

In the Earth’s layer the grayish color is called as crust and the one in reddish color is called as mantle on the left hand corner side

Image result for earth crust and mantle

Earthquake Magnitudes and their effects

If the intensity of the earthquake is between 0 to 2 it can be barely sensed when the intensity is more than 2 and less than 4 we can feel minor vibrations and sense it a little from 4 to 4.9 it is considered as small or a light earthquake range from 5 to 5.9 are considered moderate earthquakes and from the range, 6 to 6.9 are considered as strong earthquakes and sometimes this range can damage a lot. Anything above 7 is considered a major earthquake that can destroy cities and continents.


These readings are recorded on a seismograph. An earthquake starts from a point called a hypocenter inside the earth during an earthquake two types of waves are formed one is called body waves and the other is called surface waves.

Image result for hypocentre

Seismic waves

Earthquakes create shockwaves like a bell ringing known as and these travel both deep into the earth and around its surface. There are two types of seismic waves that are made, and each is quite different.


These waves travel the fastest and are called primary waves or pressure waves as they arrive at a distant location first these waves compress and stretch the rocks as they spread out P waves pass easily through both solids like rock and liquids like magma.


These slower waves arrive after the P waves and so are called secondary waves or shear waves s waves cause an up-and-down motion they traveled through solid but not liquid.

The software which can use this data to generate more efficient information, recent studies showed that before an earthquake nearby regions record very high concentrations of radioactive pair RADON and THORON this happens because right before the earthquake these gases are released on the surface from small cracks and if we can detect these gases we can predict a quake at least seven days in advance.

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