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Earth Science Themed Essays

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Earth Science Themed Essays

As India's Plates Collide

Rikesh_pic

By: Rikesh
Grade: 7
State: New York


India, a beautiful country in South Asia, is the heart of its continent. Filled with cultures and languages that go past the hidden boundaries of your imagination, India has certainly shown that heart and will are stronger than adversity. The people of India have devoted their lives to their religion, no matter what others may think of it. Languages such as Hindi and Gujarati have given Indians their own special way to communicate. Believing in such gods as Ram and Krishna has given them inspiration that led to their success and prosperity.

Women carry water in earthen jars for their children's survival. Camels stamp over the dusty soil in restless moods. Temples and mosques are filled with gods and goddesses with stunning powers. Girls and their mothers, in colorful saris, cook luscious Indian breads including chapati, roti, nan, bhakhari, puri, and parotha. Hundreds of children walk to school with excitement and wonder. But a natural force, a force they cannot control, has damaged India for centuries. It is known as the Indian earthquake zone, and it has a force that is strong enough to rumble the very heart of India.

Layers of Earth (Click to enlarge.)


The earthquakes in this zone have not only killed thousands of people, but they have affected the country India in a manner that you would least expect. It all began in 1737 in Calcutta, known as "the soul of Western India." It was a peaceful day in India, but underground, in the mantle, it surely was not. In a matter of seconds, the Indian plates began moving, when suddenly, rocks became stressed, and a faultline was created.

Suddenly, Earth began shaking and quickly got louder by the second. The rapid shaking turned into a raging roar, filled with horrible noises. That's when it happened. Objects and material began to fall and shake. The yells of children and parents spread throughout the area as the rapid shaking turned into a tremendous earthquake. "Dhartikamp!" ("Earthquake!") yelled the Indian men and women, as the pressure grew across the core of Calcutta.

In a matter of seconds, the earthquake began to spread: over the Brahmaputra River, across the Ganges, above the Narmada River, and into the plains of Kutch and Rajasthan.

Houses collapsed, and the lives of many were gone forever, leaving the living in desperation. Precious clothing, including chaniyas, cholis, panjabis, and sararas, ripped as the earthquake's power was expressed. "Madad!" or "Help!" cried the Indian women, as their lives became endangered. Blood oozed over the tar of the streets, as it became a sight of horror. Many stood in disbelief, crying and mourning for their loved ones and lost possessions. An eerie silence spread over Calcutta, signifying the earthquake's end, but the damage had been done. This earthquake in Calcutta was the most deadly in the history of India. It killed over 300,000 people and wiped out the whole city. But this zone, the Indian earthquake zone, has had far more earthquakes than this one.

In 1819, near Kutch, this horrifying tremble occurred once again. Then, in 1897, near Assam, yet another earthquake was in progress. Eight years later, in 1905, near Kangra, the disaster and the damage were repeated a fourth time. But these earthquakes in India kept on coming. In 1950, near Assam, the Indian faultline once again showed its power through massive force and strength. Finally, in 1991, near northern India, the faultline caused one more earthquake of terror, but fortunately it did not do the damage it was expected to do. The faultline remains present up to this day and probably will for a long time.

rikesh_convergent

Convergent plate boundary


How do earthquakes begin? Let me start from the very beginning. Earth is divided into four basic layers. The crust, the layer farthest from the center of Earth, is made up of hard, rocky substances, which have crumbled into dirt over the years. As you move closer to the center, you reach a layer known as the mantle. The mantle, which is 1,800 miles thick, is mostly made up of solid rock. Below the mantle is the core, which is made up of two layers known as the outer and inner core. Both of these layers are extremely hot and form the center portion of Earth.

rikesh_divergent

Divergent plate boundary


Earth's outermost layer is supposedly broken up into approximately 15 pieces known as plates. These plates independently float around on the plastic mantle. But surprisingly, various things could occur when two plates come in contact with each other. The movement of the plates strains the rocks, which then produces zones of faults. Now, the way an earthquake occurs may vary. In some cases, the first plate comes over the second plate, causing the second plate to subduct and sink deeper into the mantle, which in turn builds up pressure. But for the Indian earthquake zone and many others, two plates pile up against one another and their contact builds up a lot of heat and pressure, which eventually can trigger an earthquake.

rikesh_transverse

Transverse plate boundary


The question is, Why does this pressure occur? When any two objects, such as these two plates, rub against one another, they create friction. As a result of this friction, the plates then stick together. But the massive forces within Earth that are causing the plates to shift won't let them stick together for long. When enough of this extreme pressure builds up within the ground, the plates move in an instant, with a sudden jerking motion. Rock breaks, and shock waves shoot out from the point at which the plate moves, and the earthquake begins. This focal point, where the shockwaves are first released, is known as the epicenter of the earthquake. It receives the most pressure and damage throughout the event of any earthquake. After a major earthquake, slight movements in the rocks where the plates join together can cause additional tremors, known as aftershocks.

Earthquakes are harmful not only to the place where the most pressure occurs; they are also very harmful to the surrounding area. When an earthquake occurs, the violent breaking of rock releases energy that travels through the earth in the form of vibrations called seismic waves, including body waves and surface waves. Body waves are the fastest seismic waves. There are two kinds of body waves, compressional and shear waves. The compressional waves push and pull the rock, while shear waves make rocks move from side to side. Surface waves are long, slow waves, and they cause the most earthquake damage. According to the World Book Encyclopedia, there are two types of surface waves, love waves and Rayleigh waves. Love waves travel through Earth's surface and move the ground side to side, while Rayleigh waves make the surface of Earth roll like waves on the ocean. Almost all earthquakes spread through these waves, including the earthquakes at India.

One of the biggest problems with an earthquake is the damage that it causes. Many buildings are not constructed to stand up to high forces or violent shaking, and they collapse. Earthquakes can also cause destruction in other ways, including liquefaction. In many areas of the world, including India, the ground isn't as solid as it may seem. It may be packed with loose gravel and sand, or it may contain streams of underground running water. This type of ground will usually support a large, heavy building of some sort. But in the presence of an earthquake, the sand particles could collapse together and mix with the groundwater, turning into a liquid mass almost like quicksand. This could actually cause buildings to sink into the earth!

The tsunami, another effect of an earthquake, can cause far more damage. These humongous ocean waves are created as the ocean bottom rises and falls from the shock of an earthquake. Tsunamis can raise to heights greater than 30 meters! When they strike a coastline, they carry incredible amounts of energy and can produce the same damage as an earthquake. Earthquakes can also damage bridges, dams, and other structures. Other hazards of earthquakes include rockfalls, ground settling, and falling trees or tree branches. The shifting blocks of earth may also loosen the soil and rocks along a slope, which could then cause a landslide. In addition to this, earthquakes can even break down the banks of rivers, lakes, and other bodies of water, causing flooding.

Earthquake-Resistant Buildings (Click to enlarge.)


One major hazard of an earthquake is a fire. Fires may begin if a quake ruptures gas or power lines. The fire can wipe out a city and can spread, which can affect other cities. Other major hazards include spills of toxic chemicals and falling objects, such as tree limbs, bricks, and glass. Even sewage lines may break, and sewage may get into water supplies. The damage of an earthquake can vary so much even though the earthquake might only last a few seconds.

In India, many engineers are working to reduce the damage of earthquakes. Indian engineers have developed ways to build earthquake-resistant buildings and structures. From the smallest to the largest buildings, the simpler reinforcement techniques include bolting buildings to their foundations and providing support walls known as shear walls. These walls, which are made of reinforced concrete, help the structure resist strong rocking forces. Builders also use devices called base isolators, which absorb some of the sideways motion that would otherwise damage a building. All heavy appliances and furniture in a building must be fastened down to prevent them from falling or shaking during the event of an earthquake. Also, gas and water lines must be reinforced with flexible joints to prevent them from breaking. All these reinforcements could reduce more than half the damage of an earthquake.

Faults (Click to enlarge.)


There are many reasons why people still live near the Indian earthquake zone. For one thing, the houses and property are usually cheaper than those of a safe, protected zone. People are loyal to their country and birthplace and choose to stay where their relatives cluster. Others want a sense of adventure, or even want to show an act of bravery or courage. In many cases, scientists reside in this zone because they want to study the geology and geography of land after it has been affected by many earthquakes. They may also want to see other effects of an earthquake- prone area. These reasons may not seem right to others, but they certainly do make sense.

I chose the Indian earthquake zone for many reasons. One reason is that my parents used to reside in Gujurat, and they possess a lot of knowledge on the land and geography of India. I also chose this topic because it is important for me to learn about my country's history, and this essay was certainly a dazzling start. When I learn about disasters, I really enjoy learning how they are formed and what they can do. I have also always liked studying issues related to nature, and disasters are one of the biggest issues in nature.

God, love, and hope have always been part of Indian residents all over the country. That is why women still carry out daily activities, camels stamp over the dusty soil, and people of all ages and sizes still perish. And despite centuries of suffering, India, a country that we all thought would die in the presence of these monstrous earthquakes, still lives on and will probably never die down.

 

References

Alexander, Tom. "A Revolution Called Plate Tectonics Has Given Us a Whole New Earth." Smithsonian, January 1975, pp. 30-47.

Anderson, Don. "Seismic Tomography." Scientific American, October 1984, pp. 60-68.

Asimov, Isaac. About Earthquakes? New York: Walker and Co., 1978.

Bolt, Bruce. Earthquakes: A Primer. San Francisco: W.H. Freeman and Co., 1978.

Bramwell, Martyn. Volcanoes and Earthquakes. London: Franklin Watts Inc., 1986.

Gribbin, John. This Shaking Earth: Earthquakes, Volcanoes, and Their Impact on Our World. New York: G.P. Putnam's Sons, 1978.

Hammond, Allen. "Plate Tectonics: The Geophysics of the Earth's Surface." Science, July 2,1971, pp. 40-41.

Hermes, Jules. The Children of India. Minneapolis, Minnesota: Carolrhoda Books Inc., 1993.

Husain, Shahrukh. Focus on India. London: Evans Brothers Limited, 1986.

Kerr, Richard. "The Bits and Pieces of Plate Tectonics." Science, March 7, 1980, pp. 1059-1061.

Khandpur, Swam. Tell Me More About India. Thane: India Book House PVT LTD, 1994.

Lampton, Christopher Earthquake. Millbrook, Connecticut: The Millbrook Press, 1991.

McNally, Karen. "Earthquake." World Book Multimedia Encyclopedia California: World Book Inc., 1997.

Weil, Anne. "Plate Tectonics: The Mechanism." http://www.ucmp.berkeley.edu/geology/tecmech.html.

 

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