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Thursday, May 23, 2019

Natural disasters are often not natural Essay

Natural disasters are very much not congenital disasters, merely are in fact compassionate disasters. Discuss this statement in relation to seismic events.The word natural indicates that humans have not actord the disaster. However, human activity faeces certainly interfere with nature, which in turn may either cause a natural disaster or piddle away its cause much worse. Earthquakes can affect pot in many different ways in countries all over the world. They are a product of yearning seismic activity where plates are interacting, at a destructive of transform faults, particularly leading to a build up of strain below the Earths surface. When this tension is released the buildings, bridges, pipes etc which lie in the line of the seismic waves can often not withstand the force and strain of the earthquakes and can potentially harm people. However is it the peoples fault that the earthquake occurred in the first place? Earthquakes induced by human activity have been documente d in a some locations in the YSA, Japan and Canada.The cause was injection of fluids into deep wells for waste disposal and secondary recovery of oil, and the use of reservoirs for water supplies. Most of these earthquakes however were minor. The largest and nearly widely known resulted from fluid injection at the Rocky Mountain Arsenal near Denver, Colorado. For decades scientists have been researching induced seismicity, or how human activity can cause earthquakes. Such a link gained attention in the early 1960s when hundreds of quakes were recorded in Colorado after the Army began injecting fluid into a disposal well. There are many ways human activity can trigger earthquakes. In the 1930s for example, the construction of Hoover Dam in Arizona unleashed a burst of seismic activity in the vicinity that reached a magnitude of 5 on the Richter scale. Geothermal- muscle projects have been known to crystallize the ground shake. This process involves pumping pressurised water a mil e into the Earth, then sucking up the heated liquid to make steam and drive turbines to generate electricity. A dike cannot cause an earthquake by itself. The risk factors, specifically unstable fault lines, have to be there already.With the right conditions in place, though, a dam can trigger the event earlier than would have happened naturally, and perhaps even increase its magnitude. Human engineering has been triggering earthquakes for more than half a century says da Vinci Seeber, professor at Lamont-Doherty Earth Observatory, and manmade quakes may be more common than acknowledged. However Dr. Seeber says that distinguishing natural from triggered earthquakes is generally difficult he said Agents triggering the earthquake often refuse to admit responsibility and make it difficult to obtain the data that could prove it. Even a smell nidus increase can cause a fault to fail, Dr Seeber said humans tend to do it in two ways. One is by changing the load on the crust, typically wi th drippy lakes, which increase the load, and with quarries and oil fields, which decrease the load. The other ways is increasing the pressure of the interstitial fluid.This isnt to say that all earthquakes are caused by humans. They are typically natural occurrences. Theyre most often caused by the shifting of plates of rock under the surface od the earth. These plates move along fault lines, which are places where the differently solid rock of Earths crust has pushovered. When the plates slide against each other, or away from each other, the Earth vibrates violently. Less often, earthquakes are caused by natural occurrences like volcanic eruptions. But vibrations felt at the surface of the Earth can also result from Earth-shaking, manmade events like underground bomb testing and tap collapses. In conclusion, my view is for the most part, the accumulating stress that creates the stress build up until its great enough to overcome that friction, at which point seismic energy is r eleased violently as the blocks catch up on decades worth of motion in just a few seconds is much too large for human activities to make a difference.We can, however, affect the friction that locks up the fault. Hydraulic fracturing, where fluids are pumped into the ground at extremely high pressures to crack rocks that release natural gas and oil, has been shown to do just that in certain situations. Increasing the fluid pressure inside the fault partially de-stabilises the friction-lock, lowering the stress threshold necessary to trigger an earthquake just enough for one to occur. Despite the obvious negative effects that humans have on untimely causing an earthquake, the natural factors of the earthquake are fundamentally the reason they occur because without these then the earthquake wouldnt happen. Human impacts speed up and may make the earthquake worse however they are in fact natural disasters with human elements thrown into the equation.

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