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To Develop An Essay About The Possible Solutions That Science May Apply To Avoid Or Minimize The Side Effects Of Earthquakes


Enviado por   •  10 de Abril de 2014  •  1.536 Palabras (7 Páginas)  •  499 Visitas

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Introduction

Task

To develop an essay about the possible solutions that science may apply to avoid or minimize the side effects of earthquakes

MYP

I relate this essay with the area of interaction of Human Ingenuity because the man is investigating, creating and inventing new techniques to minimize side effects of earthquakes.

Development

Effects of Earthquakes

One manifestation of the planet's internal activity is earthquakes. The earth suffers a million quakes a year including at least 100 serious ones and 10 disastrous ones.

No other natural phenomenon is as destructive over so large an area in so a short time as an earthquake. An earthquake can, in five minutes kill hundreds of thousands of people.

The most murderous quake is supposed to have taken place in the northern province of Shensi in China in 1556, when 830,000 people were killed. On 1 November 1755, a great earthquake struck Lisbon demolishing every house in the lower part of city; sixty thousand people were killed. Some cities in Spain were also seriously affected by the Lisbon earthquake; Huelva lost most of the historical buildings and the old town had to be nearly completely rebuilt. Haiti is the last example, 12 January 2010. 222,570 people were killed, 300,000 injured, 1.3 million displaced, 97,294 houses destroyed and 188,383 damaged.

Haiti earthquake 2010

Niigata earthquake 1964

The largest percentage of the deaths and property damage that result from an earthquake is attributable to the collapse of buildings, bridges, and other man-made structures during the violent shaking of the ground. An effective way of reducing the destructiveness of earthquakes, therefore, is to build structures capable of withstanding intense ground motions, (1) (2) (3) (7). Causes of earthquakes

These are internal abrupt disturbances within the earth that result in the generation of seismic waves causing violent shaking on the earth's surface. The origin and distribution of most major earthquakes can be explained in terms of the plate tectonics theory. This theory postulates that the earth's surface is made up of a number of large, rigid plates that move relative to one another and interact at their boundaries. The severest earthquakes tend to occur at convergent plate boundaries where one plate descends beneath the other.

Three major zones of seismicity have been identified: 1) the circum-Pacific belt, which lies along plate margins around the Pacific Ocean and includes areas of the Andes Mountains and the San Andreas Fault region of California; 2) the trans-Asiatic belt, extending from the Mediterranean Europe to the Pacific, with a relatively narrow Alpine belt; and 3) the mid-ocean ridges which form a connected worldwide rift system.

Some small earthquakes occur from time to time outside of these regions. These so-called intraplate earthquakes must be explained by mechanisms other than plate motions.

Other earthquakes, usually of a minor nature, have been triggered by human activities that disturb the equilibrium of subsurface rock layers- e.g., underground nuclear testing, impounding of water behind high dams, and the pumping of liquid waste into the Earth through deep wells. (4) (5) (6)

Science and the mitigation of the effects of earthquakes

Science might play a major role in the prediction and control of earthquakes and in the minimization of side effects. If major earthquakes could be predicted, it would be possible to evacuate population centres and take other measures that could minimize the loss of life and perhaps reduce damage to property as well. For this reason earthquake prediction has become a major concern of seismologists around the world.

Investigators agree that much more has to be learned about the physical properties of rocks in fault zones before they are able to make use of changes in these properties to predict earthquakes. Science does not allow yet predicting the occurrence of earthquakes with the necessary anticipation to avoid or minimise the loss of human life.

However, science plays already and important role in the design and construction of earthquake-resistant structures. Currently this is the main solution to address the effects of earthquakes.

Development of structure resistant to earthquakes

Conventional approach

Conventional seismic design attempts to make buildings that do not collapse under strong earthquake shaking, but may sustain damage to non-structural elements and to some structural members in the building. This may render the building non-functional after the earthquake, which may be problematic in some structures, like hospitals, which need to remain functional in the aftermath of earthquake. Buildings with such improved seismic performance usually cost more than the normal buildings do.

The behaviour of building during earthquakes depends critically on its overall shape, size and geometry. Architects and structural engineers work together to ensure that the unfavourable features are avoided and a good building configuration is chosen.

Earthquake resistant buildings need to be built with ductility in them. Ductility is the ability to undergo distortion or deformation

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