The aim of this study was to investigate causes of injury during the 20102011 canterbury earthquakes. An earthquake is the shaking that radiates out from the breaking rock. The nature and cause of earthquakes kitp online talks. An earthquake is shaking or trembling of the earths surface, caused by the seismic waves or earthquake waves that are generated due to a sudden movement sudden release of energy in the earths crust shallowfocus earthquakes or upper mantle some shallowfocus and all intermediate and deepfocus earthquakes a seismograph, or seismometer, is an instrument used to. Earthquakes happen when so much stress builds up in the rocks that the rocks rupture. Earths major earthquakes occur mainly in belts coinciding with the margins of tectonic plates. Can cause major damage to poorly constructed buildings over small regions. Can the extraction of crude oil and natural gas trigger such a massive earthquake. These convection currents result in a circulation of the earth s mass. This is all due the the diffraction and spreading of the waves. In laymans language, an earthquake is the shaking of the earth by some sudden underground activities. An earthquake is a sudden tremor or movement of the earths crust, which originates naturally at or below the surface. A seismograph record of the 2011 tohoku, japan earthquake, recorded on the other side of the pacific ocean at the hawaii volcanoes national park.
Causes, effects and geographical distribution of earthquakes. Scientists can explain how most earthquakes are caused using simplified theories. These forces bring about changes on the earth surface and physical features like mountains, plateaus and rift valleys are formed. The main cause is that when tectonic plates, one rides over the other, causing orogeny collide mountain building, earthquakes. Scientists cant tell that an earthquake is a foreshock until the larger. Causes of earthquake in nepal geographical analysis. Each year there are more than 150,000 earthquakes strong enough to be felt by people and 900,000 recorded by seismometers. Lets take a look at all you need to know about earthquakes and fill your brain with knowledge. The main causes of earthquakes fall into five categories. Nepal is a nation which does not sit on a single structural plate. Faulting also occurs in response to shearing stresses. Volcanoes and human activity also cause earthquakes. An earthquake may last only a few seconds, but the processes that cause earthquakes have operated within the earth for millions and millions of years. Movement between two plates is not smooth and it causes elastic energy to gradually build up over time.
Causes of earthquakes earthquake hazard and emergency management 24 objective 2. The main cause is that when tectonic plates collide, one rides over the other, causing orogeny mountain building, earthquakes and volcanoes. The most of the earthquakes take place along the pacific ring of fire which covers the coastal region of the pacific. An earthquake is caused by a sudden slip on a fault. When the stress on the edge overcomes the friction, there is an earthquake that releases energy in waves that travel through the earths crust and cause the shaking that we feel in california there are two plates the pacific plate and the.
Asked in earthquakes, geography, volcanoes, plate tectonics. Earthquakes are caused by sudden tectonic movements in the earths crust. Earthquakes are caused by tectonic movements in the earths crust. The shaking motion of an earthquake is the result of a sudden release of stress building up within rocks of the earths crust. Schematic drawing of the tsunami generation by the bottom oscillating motion in some instances, the earthquake may initiate faults and fractures in bottom rock. Undulations of the land surface during an earthquake. Levin encyclopedia of life support systems eolss figure 2.
The most important earthquake belt is the circumpacific belt, which. These notes will also be useful for other competitive exams like banking po, ssc, state civil services exams and so on. Earthquakes earthquakes occur when energy stored in elastically strained rocks is suddenly released. Earthquakes are caused by disturbances in the interior of the earth and other causes. Earthquakes can be violent enough to toss people around and destroy whole cities. The sudden shaking or rolling of the earths surface is called an earthquake. The most important earthquake belt is the circumpacific belt. Causes and effects of earthquakes engineering essay. Data on patients injured during the darfield 4 september 2010 and christchurch 22 february.
Various societies have produced earthquake legends to explain these natural occurrences. Earthquakes can range in size from those that are so weak that they cannot be felt to those violent enough to propel objects and people into the air, and wreak destruction across entire cities. Some major causes of earthquakes on basic of its causes are. Radiating out from the epicenter, surface waves move the ground up and down and side to side, which is what causes all the damage an earthquake produces.
The deeper the earthquake, the more damage it causes. People have known about earthquakes for thousands of years, of course, but they didnt know what caused them. Surface causes volcanic causes tectonic causes surface cause. Definition, causes, measures and other details with diagram.
In particular, people believed that the breaks in the earths surfacefaultswhich appear after earthquakes, were caused by the earthquakes rather than the cause. It is caused when magma leaving the volcano are filled by rocks being pushed to the. This article talks about earthquakes, its magnitude scale, causes, types, etc. Earthquake in oceans is known as tsunami, which is equally devastating. Earthquakes occur when the ground is subjected to so much force that it fractures or breaks. Pdf earthquake is one of the most devastating natural calamities which causes sudden shaking of the earth surface. Until very recently, the cause of earthquakes was an unsolved mystery.
Evaluate the knowledge you have gained about the causes of earthquakes with this quiz and worksheet. According to wikipedia, an earthquake also known as a quake, tremor or temblor is the perceptible shaking of the surface of the earth, resulting from the sudden release of energy in the earths crust that creates seismic waves. The study of an earthquake is known as seismology to find out the causes of earthquake. Causes and measurements earthquakes the objectives of this part of the course will to be gain an understanding of the science of earthquakes so that we can answer the following questions. Earthquakes are a sudden and quick shock of the earths surface. Instead the spring or string that it is hanging from absorbs all the movement. When we feel the ground is moving or shaking this energy is released as seismic waves from the epic centre. Most of what we know about the interior of the earth comes from the study of seismic waves from earthquakes. Prior to knowing the causes of earthquake in nepal, we have to think about the land arrangement of nepal.
Earthquakes are caused by the movements of plates under the surface of the earths crust. Earthquakes are actually a type of way that the earth gets rid of. Great explosions, landslides, slips on steep coasts, dashing of sea waves, avalanches, railway trains, heavy trucks, some large engineering projects cause minor tremors. It is caused due to the energy release, which triggers waves that travel in all. Earthquakes are the result of slowmoving processes that operate within earth. The lecture will be enhanced if the instructor presents. Earthquake is a sudden violent shaking of the ground, typically causing great destruction, as a result of movements within the earths crust or volcanic action. Figure 34 graphically displays where the major earthquake zones lie. Ncert notes on important topics for the upsc civil services exam. Earth was hot when it formed, and has been cooling ever since near the surface, for each km into earth, the temperature rises by about 30deg. Earthquakes occur over much of the world and the united states. Causes and effects of earthquakes linkedin slideshare.
Some of what you will be tested on includes tectonic plates and. The disturbances inside the earth are called tectonic movements. Tsunami caused by an earthquake in the sea near sumatra on 26th dec, 2004 hit southeast asian countries including india and sri lanka. Earthquake science explained is a series of short articles for students, teachers, and parents originally published as weekly features in. Rocks crack and slip past each other causing seismic waves that make the surface of the earth vibrate. Volcanic eruptions can release huge amounts of energy that can be felt as earthquakes. Surface waves travel on earths surface and cause much of the destruction associated with earthquakes. Earthquake causes damage to the building, bridges, dams. Stick simulation of earthquakes fault action game map scales to. Landslides, triggered by earthquake, often cause more destruction than the earthquake themselves. Causes, consequences, prediction, and response boris w. Earthquake in many cases, can cause great loss of life. The movement of earths crust resulting from the release of built up potential energy between two stuck tectonic plates.
Folding and faulting compression causes rocks to fold and ultimately. When an earthquake causes the ground to shake, the base of the seismograph shakes too, but the hanging weight does not. The strain that builds up in the rock will ruptures when the elastic limit of the rock is exceeded thus released the elastic energy as seismic waves. Earthquake, any sudden shaking of the ground caused by the passage of seismic waves through earths rocks. The difference in position between the shaking part of the seismograph and the motionless part is. The most common form of earthquakes, it is caused by the movement of loose fragmented pieces of land on earths crust knowns as tectonic plates volcanic earthquake. An earthquake is sudden ground movement caused by the sudden release of energy stored in rocks, called the elastic rebound theory. The origin of tectonic earthquakes is explained with the help of elastic rebound theory.
Earthquake hazards and risks earthquake risk zmany seismologists have said that earthquakes dont kill people, buildings do. The seismicity or seismic activity of an area refers to the frequency, type and. Its like when youre teacher loses their marbles because youve asked them the same question 7 times in a row. This has long been apparent from early catalogs of felt earthquakes and is even more readily discernible in modern seismicity maps, which show instrumentally determined epicentres.
What is an earthquake and what causes them to happen. If the earthquake happens to be beneath the ocean floor, they can lead to. An earthquake is a sudden shaking of the surface of the earth by the passage of the seismic waves through earths rocks. The word natural is important here, since it excludes shock waves caused by french nuclear tests, man made explosions and landslides caused by building work. This is because most deaths from earthquakes are caused by buildings or other human construction falling down during an earthquake. Can cause serious damage in areas several hundred kilometers across. The surface of the earth, called the crust, is not one solid piece. The tectonic plates are always slowly moving, but they get stuck at their edges due to friction. Actually earthquakes occur daily around the world according to one estimate, about 8000 occur every year, but most of them are too mild to be noticeable. It sits on the limits of two structural plates, for example, indian plate and eurasian plate additionally called tibetan plate. Causes of earthquake earthquakes originate due to various reasons, which fall into two major categories via nontectonic and tectonic. Earthquake magnitude earthquake severity richter magnitude earthquake effects less than 3.
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