An earthquake (or quakes, tremors) is the shaking of the surface of the earth, caused by ￼￼the sudden movement in the Tectonic Plates. They can be extremely violent or cannot be felt by anyone.
Earthquakes are usually quite brief, but may repeat. They are the result of a sudden release of energy in the Tectonic Plates. This creates seismic waves, which are waves of energy that travel through the Earth. The study of earthquakes is called seismology.Seismology studies the frequency, type and size of earthquakes over a period of time.
There are large earthquakes and small earthquakes. Large earthquakes can take down buildings and cause death and injury. Earthquakes are measured using observations from seismometers. The magnitude of an earthquake, and the intensity of shaking, is usually reported on the Richter scale.The Richter Scale was invented by Charles Francis Richter in 1935. On the scale, 3 or less is scarcely noticeable, and magnitude 5 (or more) causes damage over a wide area.
An earthquake under the ocean can cause a tsunami. This can cause just as much death and destruction as the earthquake itself. Landslides can happen, too. Earthquakes are part of the Earth's rock cycle. The impact can be measured by a seismometer. It detects the vibrations caused by an earthquake. It puts these movement on a seismograph. The strength, or magnitude, of an earthquake is measured using the Richter scale. The Richter scale is numbered 0-9.
Scientists have never predicted a major earthquake before. They do know where earthquakes may occur, such as close to the fault lines.
When earthquakes occur the Richter Scale draws how big it is and how big its getting.
Mitigation Strategies- If you are indoors:-
- Take cover under a table or bench. If there is no table or desk, sit against a wall away from things that might fall on you and away from windows, bookcases or tall, heavy furniture.
- Wait in your safety spot until the shaking stops and then check to see if you are hurt. Check others around you too. Move carefully and look out for fallen things.
- There may be aftershocks or smaller earthquakes quite soon after. So be prepared.
- If you want to leave the building after the shaking stops , use the stairs, never use lifts.
If you are outdoors :-
- Stay outside and move away from buildings, trees, lights and power lines. Crouch down and cover your head!
History[change | change source]
Earthquakes sometimes hit cities and kill hundreds of thousands of people. Most earthquakes happen along the Pacific Ring of Fire but the biggest ones mostly happen in other places. Tectonically active places are places where earthquakes or volcanic eruptions are frequent.
The ancient Chinese used a device that looked like a jar with dragons on the top surrounded by frogs with their mouths open. When an earthquake occurred, a ball in each dragon's mouth would drop out of the dragon's mouth into the frog's. The position of the frog which received a ball indicated the direction of the earthquake. This was one of the first tools to help figure out where an earthquake originated from.
Causes of an earthquake[change | change source]
Main article: plate tectonics
Earthquakes are caused by tectonic movements in the Earth's crust. The main cause is that when tectonic plates , one rides over the other, causing orogeny collide (mountain building), earthquakes.
The boundaries between moving plates form the largest fault surfaces on Earth. When they stick, relative motion between the plates leads to increasing stress. This continues until the stress rises and breaks, suddenly allowing sliding over the locked portion of the fault, releasing the stored energy as shock waves. Such faults are San Andreas fault in San Francisco , Rift valley in Africa etc
Earthquake fault types[change | change source]
There are three main types of geological fault that may cause an earthquake: normal, reverse (thrust) and strike-slip. Normal faults occur mainly in areas where the crust is being extended. Reverse faults occur in areas where the crust is being shortened. Strike-slip faults are steep structures where the two sides of the fault slip horizontally past each other.
Earthquake clusters[change | change source]
Most earthquakes form part of a sequence, related to each other in terms of location and time. Most earthquake clusters consist of small tremors which cause little to no damage, but there is a theory that earthquakes can recur in a regular pattern.
A foreshock is an earthquake that occurs before a larger earthquake, called the mainshock.
An aftershock is an earthquake that occurs after a previous earthquake, the mainshock. An aftershock is in the same region of the main shock but always of a smaller magnitude. Aftershocks are formed as the crust adjusts to the effects of the main shock.
Earthquake swarms are sequences of earthquakes striking in a specific area within a short period of time. They are different from earthquakes followed by a series of aftershocks by the fact that no single earthquake in the sequence is obviously the main shock, therefore none have notably higher magnitudes than the other. An example of an earthquake swarm is the 2004 activity at Yellowstone National Park.
Sometimes a series of earthquakes occur in a sort of earthquake storm, where the earthquakes strike a fault in clusters, each triggered by the shaking or stress redistribution of the previous earthquakes. Similar to aftershocks but on adjacent segments of fault, these storms occur over the course of years, and with some of the later earthquakes as damaging as the early ones. Such a pattern occurred in the North Anatolian fault in Turkey in the 20th century.
Tsunami[change | change source]
Main article: Tsunami
Tsunami or a chain of fast moving waves in the ocean caused by powerful earthquakes is a very serious challenge for people's safety and for earthquake engineering. Those waves can inundate coastal areas, destroy houses and even swipe away whole towns. This is a danger for the whole mankind.
Unfortunately, tsunamis can not be prevented. However, there are warning systems which may warn the population before the big waves reach the land to let them enough time to rush to safety.
Earthquake-proofing[change | change source]
Main article: Earthquake engineering
Some places, such as Japan or California, have many earthquakes and many inhabitants. There, it is good practice to construct houses and other buildings which will resist collapse in an earthquake. This is called seismic design or "earthquake-proofing".
Earthquake-proof buildings are constructed to withstand the destructive force of an earthquake. This depends upon its type of construction, shape, mass distribution, and rigidity. Different combinations are used. Square, rectangular, and shell-shaped buildings can withstand earthquakes better than skyscrapers. To reduce stress, a building's ground floor can be supported by extremely rigid, hollow columns, while the rest of the building is supported by flexible columns inside the hollow columns. Another method is to use rollers or rubber pads to separate the base columns from the ground, allowing the columns to shake parallel to each other during an earthquake.
To help prevent a roof from collapsing, builders make the roof out of light-weight materials. Outdoor walls are made with stronger and more reinforced materials such as steel or reinforced concrete. During an earthquake flexible windows may help hold the windows together so they don’t break.
Sources[change | change source]
- ↑Earth Science. Austin, Texas 78746-6487: Holt, Rinehart Winston. 2001. ISBN 0-03-055667-8.
- ↑ 2.02.1"What are aftershocks, foreshocks, and earthquake clusters?".
- ↑"Repeating earthquakes". United States Geological Survey. January 29, 2009. Retrieved May 11, 2009.
- ↑"Earthquake swarms at Yellowstone". USGS. Retrieved 2008-09-15.
- ↑Amos Nur (2000). "Poseidon’s horses: plate tectonics and earthquake storms in the late [Bronze Age Aegean and Eastern Mediterranean"]. Journal of Archaeological Science27: 43–63. doi:10.1006/jasc.1999.0431. ISSN 0305-4403. http://water.stanford.edu/nur/EndBronzeage.pdf.
- ↑"Earthquake storms". Horizon (BBCtv series). 9pm 1 April 2003. Retrieved 2007-05-02.
- ↑USGS Poster of the Near the East Coast of Honshu, Japan Earthquake of 11 March 2011 - Magnitude 8.9
- ↑Pacific Tsunamy Warning Center
Other websites[change | change source]
We have provided below essay on earthquake under two categories named short essay on earthquake and long essay on earthquake. We are here in order to help students to fulfill the tasks they are provided with in their classrooms or any competition organized for essay writing during national or international events celebration in the schools or colleges. All the essays are written by the professional content writer by using simple and easy words with latest informations especially for the students of class 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, and 12th standard. They can select any of the essays given below under various words limit accroding to their need and requirement:
Essay on Earthquake
Short Essay on Earthquake
Following are the short essays on earthquake for students under words limit of 100, 200 and 300 words. Students can use any of these according to their need and requirement in the schools.
Earthquake Essay 1 (100 words)
Earthquake is the trembling or shaking movement of the surface of earth. It is a sudden violent shaking of the earth surface occurs naturally and causes great destruction because of the strong movements within the earth's crust or volcanic action. It is a natural disturbance which can be characterized as convulsion or concussion of the ground. It originates at any point within the crust and pushes a mass of rock to slip suddenly. A huge energy gets released and travels through rocks as waves, which causes vibrations and shaking of the earth surface. The word earthquake reveals its meaning very clearly (earth means ground or soil and quake means shake or tremble).
Earthquake Essay 2 (200 words)
Earthquake is one of the dangerous and life threatening natural disaster which can come anytime and anywhere on the earth. Most of the earthquakes come with minor tremors however larger earthquakes with strong tremors generally begins with slight tremors but soon gets changed into more violent shocks. Stronger earthquakes generally end up with huge and forced vibrations at long distance from the main point of arousal. It gradually diminishes with reduced aftershocks. The focus of earthquakes becomes the subterranean point where it originates. Magnitude and intensity of the earthquake can be measured with the help of variety of scales such as Richter scale, moment magnitude scale, modified Mercalli scale, etc.
Earthquake is a life threatening event that responsible for the huge damage to the living and non-living beings. Earlier, it was quite hard to imagine the intensity of the earthquake before its occurrence. However, now-a-days, it has become easy to estimate the magnitude and intensity of earthquake because of the instrumental advancement in the world. People, in the ancient time, believed that earthquake occurs as mother earth was angry with them. It was Aristotle (a great Greek philosopher) who relate the occurrence of earthquake to some physical factors. According to him, the compression of air within the arch escapes cause shakes of some part of the earth surface and called as volcanic activity.
Earthquake Essay 3 (300 words)
Earthquake is a natural calamity can occur anytime and anywhere on the earth surface, cause lots of disturbance of to the living beings and useful natural resources. If we think about the earthquake, we also think that nothing is more destructive than this natural calamity. Earthquake has its long devastating history from the ancient time all over the world however its monotonous regularity makes us more fearful. Earth crust consists of several unfixed solid rock faces which move slowly below the surface under the range of millimeters to kilometers. The rate of movement increases with the thickness of plates. Such huge moving plates get separated from other plates and get out of their boundaries. Earthquake occurs when such moving plates clash with each other and separate.
Sometimes volcanos (located around edges of the Pacific Ocean, known as Ring of Fire) bursts and releases lots of lava, gas, etc which causes pressure and imbalance within the earth surface and produces earthquake waves in the surrounding areas. Thus, volcanic activity within the earth surface is one of the reasons for earthquakes. Faults created by the volcanic activitiy are filled up by the strong earht surface movement which causes tremor. Everyone should take care of them when earthquake occurs by following some precautions like:
- People should stay calm and stay inside or outside the door but away from windows, buildings and power lines.
- They should stand against the wall near to the center of building, at doorway and crawl under some heavy furnitures like a desk or table.
- Never use flammable things like matches, candles, or any other flame as they caught fire with broken gas lines.
- Never use elevators as they may stuck.
- If someone is in the running car, he/she must stop the car and stay inside until the earthquake stops.
Long Essay on Earthquake
Earthquake Essay 4 (400 words)
Earthquake is a natural calamity which has power to destroy human lives in few seconds. It is lonely responsible for the huge damage to living and non-living beings. Earlier, people were unaware of the reasons of earthquake occurrence and the extent of damage. They believed that earthquake occur whenever mother earth become angry with them. It was Aristotle (a great Greek philosopher) who made people aware that earthquake occur because of some physical factors. He told that, some parts of land moves whenever air compressed within the arch escapes which is called as volcanic activity. Earthquake waves cause movement in the surrounding areas because of air pressure and imbalance.
Another reason of earthquake occurrence is isostatic adjustment. Earth surface contains some raised and depressed blocks which make balance of earth surface however the balance disturb when blocks moves revolving on units of axis. Raised blocks get down and cause imbalance on the earth surface which inturn cause earthquake. Generally, it occurs in the volcano prime areas, under the feet of mountains and hills. However, it is not sure that earthquakes do not occur in other places. Earthquake may occur anytime in any part of the world. Some of the earthquakes become weak however some of them become very strong with huge force which may shake the earth suface far away from the centre point.
Earthquakes with huge intensity become really dangerous and cause severe damage. According to the scientific study with the help of Seismograph, there are some secondary waves and tertiary waves in the earthquake. There are various measurement scales which can accurately measure the intensity of earthquake such as Mercall’s scale, Richter scale, moment magnitude scale, etc. Himalaya zone, the Ganga, Deccan Plateau, the Brahmaputra valleys, etc are the earthquake prone areas in India. Kutch (Gujarat, India) earthquake of the year 1819 was so massive (calculated 8 on Richeter Scale) and affected a huge area (around 5000 square kilometers depressed by 15 feet and 1500 square kilometers raised by 50 feet). More than 10000 people were killed in the earthquake event of Latur and Osmanabad districts of Maharashtra on 30th of September in 1993.
Earthquake is the result of release of elastic energy after forceful tectonic plate movements. Elastic energy released in the form of seismic or shock waves which travels for a long distance outwards in all directions from the centre point (a place of maximum destruction). High-rise buildings and ancient structures of the cities (like Delhi) can be badly affected by the seismic force of earthquake.
Earthquake Essay 5 (600 words)
Earthquake is a very dangerous natural disaster which occurs as a sudden shaking movement of rocks in the earth's crust. Some of the earthquakes of low intensity become less dangerous however earthquakes having high intensity become very dangerous and can be extremely violent especially in the areas it occurs. There is no any fix duration for the occurrence of earthquake, it may occur anytime and anywhere for any duration. It may be brief but repeat many times a day. Earthquake is the result of sudden energy release within the surface of earth. This released energy under earth crust creates powerful seismic waves which travel through the earth surface. The frequency of waves and type and size of earthquake is measured by the help of seismology which involves the use of seismometer.
Large earthquakes may destroy things to a great extent as they take down huge buildings, cause injury and thus death of people. There are various scales used to measure the intensity of shaking and the magnitude of an earthquake. The scale showing magnitude 3 or less indicates that the earthquake is less harmful however the scale showing magnitude 7 or more causes huge level damage over a wide range of area. Earthquake which occur under the ocean take the form of a tsunami. It is a giant form which can cause death and destruction to the living and non-living things. High intensity earthquakes give rise to the landslides in the surrounding areas.
In the ancient time, people in China were used a device in order to guess the occurrence of earthquake. The device was similar to the jar having dragons on top and surrounded by frogs with open mouths. They guess the occurrence of earthquake by the exchange of fitted ball in dragon's mouth to the frog's mouth. The direction of earthquake was decided by the position of frog receiving a ball. This device was an effective tool in the ancient time to figure out the origin of an earthquake.
Causes of Earthquake
- One of the main reasons of the earthquake is plate tectonics which causes tectonic movements in the earth surface. Tectonic plates under the earth surface collide to each other and ride over the other which becomes the reason of mountain formation, earthquakes and volcanoes. This process releases a huge level of energy which creates a force and thus surface movement.
- Geological faults are also the reason of earthquakes. There are various forms of faults however three main types are normal fault, reverse fault (also called thrust fault) and strike-slip fault. Normal faults generally occur in the areas with extended crust, reverse faults occur in the areas with shortened crust and strike-slip faults occur in the areas where two fault sides slip horizontally.
- Most earthquakes become the part of a sequence of earthquake clusters which can recur in a regular pattern and related to each other in terms of location and time. Such earthquakes cause less damage however larger earthquakes (mainshock) create a foreshock (an earthquake of smaller magnitude) and cause much damage.
A series of earthquake can occur in the variety of earthquake storm whenever earthquake hit a fault in the clusters. Tsunami is a dangerous form of earthquake which occur as a result of a chain of fast moving waves in ocean because of powerful earthquakes. It is a very serious challenge for the people's lives, safety as well as earthquake engineering as they can engulf coastal areas, swipe away whole city, damage houses and many more. It is sad to say that it cannot be prevented however people can be warned through various warning systems to run away and save lives.