The Science Behind Earthquake and Earth Movement
‘Earthquake' is one of the notable sudden changes in the world. It is a natural catastrophe. Many destructive activities in the world have been caused by the earthquake. Earthquake causes enormous damage and casualties. It is estimated that, In the last 4000 years, the earthquake killed approximately 15 million people in the world. Earthquake plays a significant role in changing the earth's landforms. Through an earthquake, the course or channel of the river is changed. It also forms the mountain and plateau. An earthquake occurs in small area-wide. Everyone on earth should have adequate knowledge about the earthquake.
Earthquake:
If the earth's interior trembles for any reason, generally it is called an earthquake. When a massive amount of energy (difference in temperature and pressure) is released inside the earth, an immense jerk and vibration are created which causes an earthquake.
An earthquake is created
by a kind of wave. This wave spreads around the earth's surface from the place
of its origination. In the final stage, this wave takes lives and damages
buildings. The place where an earthquake is originated is called 'Focus'.
Earth's upper point which is vertical from focus is known as 'Epicentre'.
Earthquake's vibration energy is decreased as the distance increases from the focus. When the vibration of the earthquake flows up towards the surface, the energy is diminished. The depth of focus point can be 5-1100 kilometres or more than that. There are 3 types of focus (according to the position of focus point)
i. Shallow Focus
ii. Medium Focus
iii. Deep Focus
Earthquake Waves:
It has been already mentioned that the origination of earthquake is caused by the wave. According to the position of the focus point, Earthquake Wave is 2 kinds.
i. Body Wave
ii. Surface Wave
'Body Wave' flows inside the earth and the 'Surface Wave'
outpours the upper part and surface of the earth.
Body Wave is 2 types:
i. P Wave (Primary Wave)
ii. S Wave (Secondary Wave)
The primary wave's character is vertical type. It is convulsed by contraction and expansion. It can be transferred into any medium. This wave slightly changes the position of the stone. Then comes 'Secondary Wave'. This wave trembles objects in the right angel over and again. This wave changes the shape of objects and infrastructures. Secondary Wave creates more destruction and casualties for buildings.
'The Surface Wave' is also known as 'L Wave'. This wave raises like water. This type of wave flows 'horizontally' through the surface.
The wave of the earthquake is measured by 'Seismograph' which is placed in different places of the earth. A seismograph can find the 'Source Point' and calculate the immensity of the earthquake.
Seismograph:
A machine that is placed on the surface to record the tremors of the earth's interior is known as 'Seismograph'.
This tool is hanged freely with a heavy squint stick and its quadrant is attached to the earth. When the temblor wave reaches the machine, then the heavy hanged object's inertia keeps the object stable, but the earth and the squint stick keep oscillating. There is a pen adjoined with the hanging object's top that marks in the graph paper by following the earthquake. Seismologists calculate the strength and intensity of the marked lines in the graph.
Causes of Earthquake:
1 . Collision of Plates: Collisions of plates create
cracks that conduce earthquakes. The plates frequently move inside the earth.
The boundary of the moving plates is more active. The movement of these plates
is along the dislodgement of the earth, where more earthquakes occur.
2. Volcanism: Earthquake also occurs because of the 'Locomotion Of Magma' along the fault line. By this, contortion and deviation of rock happen.
3. Earth Movement: Earth movement is one of the prominent causes of earthquakes. Earth's heated inside part is not static. It is always convulsing and wiggling somehow. These convulsions affect the surface directly. Among those some sudden convulsions are abruptly felt, which are considered as the eminent reasons earthquake.
4. Heat Radiation: Earth is radiating from ancient times. Though the earth's surface is cool and hard due to heat radiation, the earth's inside part is extremely heated. The heat radiating process is continuously running in various ways.
5. Underground Steam: In many ways, a sort of vapour is produced underground. If the pressure of the surface reduces for any reason, the hard rock layer would become liquid. So, plenty of water vapour will be produced. If the quantity of vapour rises steadily, it will hit the surface with massive velocity and this heavy earthquake is felt. This earthquake will continue until the vapour releases across the weaker perforation or crack.
6. Enhancement of Surface Pressure: In some low places, if sediment is deposited consecutively then that place becomes remarkably thick. So, the pressure of that place increases at a higher rate than before. Then, the heavy sedimentary rock layer is lessened down. At the time of lessening the rock layer, a concussion is created and the earthquake is felt in the adjacent areas.
7. Balance: Earthquakes can occur to maintain the balance of the rock layer in different places. If the pressure of any rock layer increases then it abates down. To balance up 'substrate', the rock layer of the surrounding area is raised. In some stages of this process, an earthquake can happen.
8. Underground Incendiary Substance: Besides eruption sometimes earthquake occurs by the pressure of underground igneous element.
9. Percolation of Water in Underground: When the water of the surface is entered through different cracks and narrow holes, the effect of its heat creates a huge amount of steam. When the amount of steam raises, it creates more 'uphill pressure'. Which causes 'Earth Movement'.
10. Deviation and
Isolation of Stone: When massive stones are
isolated, those huge stones fall forcefully from high hill tracts. This causes
quakes in the surrounding areas.
11. Glacier: Occasionally, gigantic snowflakes fall from the high mountains in the glacier region.
12. Fire of Underground
Cave: At times, the roof of
the large cave collapses when the roof becomes weak and the earth trembles.
14. The Impact of The
Explosion: Nuclear-power
possessing countries often explode bombs in the subterranean region.
Results of Earthquake:
1. Creating innumerable
deviations, foldings and cracks on the surface
2. Change in the
direction of the river course
3. Vicissitudes of the
ocean floor
4. Blow on
infrastructure
5. Heavy damage by
landslide
6. Glacier
7. Flow of tsunami
Written by Sami Abdullah
Keep it up broh
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