Cause & Effect Essay: Natural Disasters and Their Causes. Natural disasters happen all over the world, and they can be utterly devastating for people’s lives and the environments in which they live. Although natural disasters are caused by nature and there is nothing that we can do to prevent them happening, there are many different natural causes that lead to natural disasters, and being aware Estimated Reading Time: 3 mins May 04, · NATURAL DISASTERS A natural disaster is a major adverse event, which can cause loss of life or property damage, and typically leaves some economic damage. There are many types of natural disasters: avalanches, earthquakes, volcanic eruptions, floods, tsunamis, blizzards, droughts, hailstorms, tornadoes, wildfires. If an adverse event occurs in an area without vulnerable population, it Natural disasters are catastrophic events that are caused by weather and geological phenomena. Natural disasters can cause damage to infrastructure or even injuries and death. Floods, earthquakes, hurricanes, volcanic eruptions, and tsunamis are among most frequent phenomenons and can even affect the political and economical state of a country
An Essay On Natural Disasters - Words | Internet Public Library
A natural disaster is unforeseen, severe and immediate. Pollution, ozone depletion in the stratosphere and global warming come in this category. Image Courtesy : go. The destructive potential of any natural hazard is estimated basically by its spatial extent and severity.
Spatial extent upto which the effect of a disastrous event could be felt may easily be classified into small, medium and large scales. The phenomenon extending from a few kilometers to a few tens of kilometers are termed as small scale. Growing industrialisation and unjustified exploitation of natural resources have brought our echo system to a verge of non-reversibility and imbalance.
This has led to a threat from a set of natural hazards like pollution, global warming and ozone depletion on large or global scale. The management aspect of disaster may be classified as: a early warning system; b rescue operations; c relief operations; d rehabilitation; and e long range planning. The most important is the early warning systems. Unless sufficient advance notice is available, evacuation of the population likely to be affected cannot be undertaken.
There are two aspects of early warning system. One is the availability an essay on natural disasters an effective technique to forecast the disaster with its extent and the other is effective communication of the same to the civil authority responsible for rescue operations.
In some phenomena, such as cyclones, flood, etc. the time available to respond to the hazard is of the order of a few days. Hence early warning, communication, and rescue operations are possible. But, in a few cases like flash floods, microburst, etc. The human-activity-induced hazards like pollution and global warming have already started showing their precursors, an essay on natural disasters, giving sufficient time to control and avoid these hazards by long term planning.
On the contrary, in earthquakes no proven methods has yet been evolved to give any prior warning and so post-hazard mitigation is the only alternative. Role of Communication For a developing country like India, the role of communication in disaster mitigation is extremely critical.
These can neither be provided in a short span of time available for mitigation nor are there resources to do so. We have to depend on existing links, many of which completely break down during the disaster. The various types available for dissemination of disaster warning as well as arranging mitigation are: a land line links; b underground cable links; c wireless links; d microwave LOS ; and e satellite links. The only effective communication which is likely to remain completely or partially unaffected is the satellite link.
This assumes that the earth stations at the two ends are suitably located to remain unaffected. The most effective way of dissemination of warning is Disaster Warning System DWS used by the IMD for issue of cyclone bulletin to the coastal areas.
Experience has shown that it remains completely unaffected under the severest cyclonic condition. However, the system is limited to one way communication only. The only addition required is the missing link between the nearest earth station to police headquarters.
This would be a cost effective and reliable communication system for disaster warning and mitigation, an essay on natural disasters. The theory of plate tectonics offers a comprehensive explanation for several geological phenomena — continental drift, mountain building and volcanism, and, of course, earthquake.
According to this theory, when the molten mass that was the earth billions of years ago cooled down, the crust that was formed was not one homogenous piece but broken into about a dozen large plates and several smaller ones with their thickness ranging from 30 km down to the lithosphere at depth of about km or so.
The plates are in incessant motion, with speeds of about 1 cm to 5 an essay on natural disasters a year. This mobile jigsaw puzzle is what is termed as the continental drift, which results in the formation of mountains, midoceanic ridges, ocean trenches, volcanoes and seismic energy buildup. Where two places converge or collide, a deep trench forms and one plate is deflected downwards into the asthenosphere which lies below the crust and the lithosphere.
When two thick continential plates collide, rocks on the an essay on natural disasters are relatively light and too buoyant to descend into the asthenosphere. The result is a huge zone of crushing, with rocks and other materials being folded. And this is how the Himalayas have emerged or, in fact, are continuing to emerge. As the deformation of the plate margins goes on, energy builds up in rocks in the form of elastic strain which continues till it exceeds their elastic limits and the rocks give way.
The sudden release of stored elastic energy causes earthquakes. Earthquakes in India are caused by the release of elastic strain energy created and replenished by the stresses from the collision between the Indian plate and the Eurasian plate.
The most intense earthquakes occur on the boundaries of the Indian plate to the east, north and west. In the Indian plate, faults are created when this rubs against the Eurasian plate. When an earthquake occurs along a fault line within the plate, an essay on natural disasters, it is called an intra-plate earthquake. The majority of the earthquakes occur along plate boundaries. Earthquakes are also caused by volcanic activity. Construction of large water reservoirs may also cause earthquakes—these are called reservoir-induced earthquakes.
The movement of the plates and occurrence of earthquakes seem to be concentrated in certain areas or zones of the earth. Based on intensity and frequency of occurrence, world map is divided into the following earthquake zones or belts—. These represent the eastern and western margins of the Pacific Ocean respectively.
The occurrence of maximum number of earthquakes in this region is an essay on natural disasters to four ideal conditions—. Also called the Mediterranean Belt or Alpine-Himalayan Belt, it accounts for about 21 per cent of the total seismic shocks. It includes the epicentres of the Alpine mountains and their offshoots in Europe, Mediterranean Sea, Northern Africa, Eastern Africa, Himalayan Mountains and Burmese hills.
The epicentres of this region are along the mid-Atlantic Ridge and the islands near the ridge. This belt represents the zone of moderate and shallow focus earthquakes—the reason for this being the creation of transform faults and fractures because of splitting of plates followed by their movement in the opposite direction. Based on seismic data and different geological and geophysical parameters, the Bureau of Indian Standards BIS had initially divided the country into five seismic zones.
Inhowever, an essay on natural disasters, BIS redefined the seismic map of India by merging zones I and II. Thus India has four such zones now—II, III, IV and V.
There is thus no part of the country that can be termed earthquake free. Of the five seismic zones, an essay on natural disasters, zone V is the most active region and zone I shows least seismic activity. The entire north-eastern region falls in zone V. Besides the North- East, zone V includes parts of Jammu and Kashmir, Himachal Pradesh, Uttarakhand, Rann of Kachch in Gujarat, northern Bihar and the Andaman and Nicobar islands. One of the reasons for this region being prone to earthquake is the presence of the young-fold Himalayan Mountains here which have frequent tectonic movements.
Zone IV which is the next most active region of seismic activity covers Sikkim, Delhi, remaining parts of Jammu and Kashmir, an essay on natural disasters, Himachal Pradesh, Bihar, an essay on natural disasters, northern parts of Uttar Pradesh and West Bengal, parts of Gujarat and small portions of Maharashtra near the west coast.
Zone III comprises Kerala, Goa, Lakshadweep, remaining parts of Uttar Pradesh and West Bengal, an essay on natural disasters, parts of Punjab, Rajasthan, Maharashtra, Madhya Pradesh, Orissa, Andhra Pradesh and Karnataka.
The remaining states with lesser known activity fall in zone II. The states of Jammu and Kashmir, Punjab, Himachal Pradesh, Uttar Pradesh and Bihar, the Bihar-Nepal border, the Rann of Katchh in Gujarat and the Andaman Islands fall into the unstable belt which stretches right across the globe. The high seismicity of the Indian subcontinent arises from the tectonic disturbances associated with the northward movement of the Indian plate, which is underthrasting the Eurasian plate.
The Himalayan region has been the site for great earthquakes of the world of magnitude greater than 8. The high seismicity region extends from Hindukush in the west to Sadiya in the northeast which further extends down to the Andaman and Nicobar Islands. Different institutions including the Indian Meteorogical Department and the Indian School of Mines, have after a study of mechanics of several earthquakes in the north- eastern region found that the thrust faulting was generally indicated along with Dawki fault and the Indo-Burma border.
Teiedemann, a member of the Earthquake Engineering Research Institute of the Seismological Society of America, said in that the increased interplay activity near the north-eastern boundary in the Indian plate coupled with thrusting of the Himalayan Burmese sector pointed to the danger of earthquakes in the region, an essay on natural disasters.
There are three kinds of seismic waves. Waves that move the fastest are called primary, or P, waves. These waves, like sound waves, travel longitudinally by alternate compression and expansion of the medium, like the movement of the bellows of an accordion. Somewhat slower are the secondary, or S, waves which propagate transversely in the form of snakelike wriggles at right angle to the directions of travel.
These cannot travel through liquids or gases. They rise to feet or more and cause damage when they break on habitated coasts. All three kinds can be detected and recorded by sensitive instruments called seismographs. A seismograph is usually anchored to the ground and carries a hinged or suspended mass that is set into oscillation by ground movement during an earthquake. The instrument can record both horizontal and vertical ground movement in the form of wavy lines on paper or film.
From the record, called a seismogram, it is possible to find out how strong the quake was, where it began and how long it lasted. The location of the epicentre of a quake is determined from the time of arrival of the P and S waves at the seismographic station. Since P waves travel at a speed of about 8 km per second and S waves at 5 km per second, it is possible to compute the distance of their origin from the seismic record.
If the distance from three stations are computed, the exact location can be pin pointed. A circle of appropriate radius is drawn around each an essay on natural disasters. The epicentre lies where the circles intersect.
The magnitude is a measure that depends on the seismic energy radiated by the quake as recorded on seismographs. The intensity, in turn, is a measure that depends on the damage an essay on natural disasters by the quake.
It does not have a mathematical basis but is based on observed effects. Devised by the American seismologist, Charles Francis Richter, inthe Richter scale is not a physical device but a logarithmic scale based on recordings of seismographs, instruments which automatically detect and record the intensity, direction and duration of a movement on the ground.
The scale starts at one and has no upper limit. On this scale, the smallest quake felt by humans is about 3. The strongest quake ever recorded had a magnitude of 8. Richter magnitude effects are confined to the vicinity of the epicentre. The Richter scale has been immensely modified and upgraded since it was introduced. It remains the most widely known and used scale for measuring the magnitude of an earthquake. For measurement of the intensity of an an essay on natural disasters, the Modified Mercalli Intensity Scale is used.
The point Mercalli scale measures the intensity of shaking during an earthquake and is assessed by inspecting the damage and interviewing survivors of the earthquake.
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Natural disasters are catastrophic events that are caused by weather and geological phenomena. Natural disasters can cause damage to infrastructure or even injuries and death. Floods, earthquakes, hurricanes, volcanic eruptions, and tsunamis are among most frequent phenomenons and can even affect the political and economical state of a country A natural disaster is a sudden and terrible event associated with the natural process of Earth. It can cause great damage to our planet and loss of people’s lives. It is really horrible and hard to stop. There are many different types of disasters due to different natural conditions. Some of them are similar and have connections with each other May 04, · NATURAL DISASTERS A natural disaster is a major adverse event, which can cause loss of life or property damage, and typically leaves some economic damage. There are many types of natural disasters: avalanches, earthquakes, volcanic eruptions, floods, tsunamis, blizzards, droughts, hailstorms, tornadoes, wildfires. If an adverse event occurs in an area without vulnerable population, it
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