Disaster

 

1. What is Disaster?

A disaster is a natural or man-made (or technological) hazard resulting in an event of substantial extent causing significant physical damage or destruction, loss of life, or drastic change to the environment.

In nature catastrophes such as floods, drought, earth quake, tsunami, happen from time to time causing immense damage to life and property.

Disasters caused by human activities such as fires, accidents, epidemics are no less sudden than natural disasters and may be equally devastating.

The Indian sub-continent is highly prone to natural disasters. Floods, droughts, cyclones and earthquakes are recurrent phenomena in India.

1.1 Types of Disasters

There are two types of disasters namely: 

Natural disasters 

Man-made disasters.

1.2 Natural Disasters

These are major adverse event resulting from natural processes of the Earth e.g. floods, hurricanes, tsunamis volcanic eruption earthquakes truncations and other logic processes. The severity of a disaster is measured in lives lost, economic loss and the ability of the population to rebuild. Some natural disasters are as follow:

• Earthquake

These are usually caused when rock underground suddenly breaks along a fault. This sudden release of energy causes the seismic waves that make the ground shake. When two plates are rubbing each other, earthquake occurs. Earthquake is measured in Richter scale (discovered by Dr Charles Richter in 1930). Following are the impact of earthquake,

Impact on Human: An earthquake may cause injury and loss of life, road and bridge damage, general property damage. And aftermath may bring diseases, lacks of basic necessities, mental consequences such as panic attacks, depression etc. In Nepal April 2015, earthquake killed nearly 9000 people and injured nearly 22000. It was of 7.8-8.1 on Richter scale.

• Shaking and Ground Rupture

 This way results more or less severe damage to the buildings and other rigid structures. The severity depends upon the complex combination of the earthquake magnitude and distance from the epicenter. Earthquake on 26th January 2001 called as in Kutch District of Gujarat, it was India's 52nd Republic Day at 8:46 AM. It is also called as Bhuj-earthquake. The magnitude of the earthquake was 7.7 on the Richter scale. Earthquake magnitude higher than 6 on Richter scales are very dangerous.

• Tsunami

Tsunamis are long wavelength, long-period sea waves produced by the sudden of abrupt. Movement of large volumes of water including when an earthquake occurs at sea.

Generally, Tsunami arises at Pacific Ocean, where Alaska, Japan, Philippines other Islands of South-East Asia, Indonesia and Malaysia included. Tsunami also occur in Myanmar, Sri Lanka and other coastal areas of India in Indian Ocean. On 26th December, 2004 a magnitude 9.1 earthquake whose epicenter was located in Indonesia's, Sumatra coast recorded most powerful tsunami in history. It killed around 230000 people of 14 countries. India was also affected on the Andaman and Nicobar Islands and Southern coastal areas.

• Volcano

It is a circular vent or fissure in earth's crust through which lava, ash, rock and gases erupt. Volcanoes are found in three states' extinct, dormant and active. These are as follow :-

(i) Extinct Volcano: An extinct volcano will never erupt again e.g. Mt Kulal in Kenya, Mt Buninayong in Australia, etc.

(ii) Dormant Volcano: A dormant volcano has not erupted in last 2000 years e.g. Kilimanjaro (Tanzania), etc.

(iii) Active Volcano: An active volcano has erupted recently and is likely to erupt again e.g. Kilanea (Hawaii), Mt Etna (Italy), Nyamuragira (Congo), Mt Fuji (Italy).

Note:

Ring of Fire: It is a volcanic chain surrounding the 'Pacific Ocean'. It is famous for its regular earthquake and volcanic activity. More than half of the world's active volcanoes above sea level form part of the ring.

Reason of Volcanic Eruption: Volcanic eruption is not related with any artificial reasons, this is only result of plate movement and other related reasons like magma rises through cracks of Earth's crust.

• Cyclone

It is a large-scale air mass that rotates around a strong center of low atmospheric pressure. 30° North and 30° South is the region of cyclone. A cyclone can be widespread up to 500 to 1000 km and height of up to 12-14 km. A fully mature cyclone develops a calm center, called eye of the cyclone. The eye is an area of very low air pressure. There are generally no clouds in the eye and the wind is calm. Diameter of eye is about 10-50 km.

Cyclones have different names around the world which are given below,

• Hurricane in the Atlantic Ocean and North-Eastern Pacific Ocean.

• Typhoon in South East Asia.

• Cyclone in Indian Ocean.

Effects of Cyclone

The destruction from a tropical cyclone depends mainly on its intensity, its size and its location. The main effects are: cloud, heavy rain, strong wind, flooding large storm and tornadoes. There is high rise in sea-line hence sailors have risk of life. These cyclones show most effect in Odisha, Andhra Pradesh and Bengal.

• Flood

Usually, dry land submerges with over flow of water for several day is called flood. Sometimes water resources (river, lakes and ponds) receives too much extra water, either from heavy rain or other natural disasters. Flood can happen gradually or can happen suddenly due to heavy rains, breach of the water storage and control structures, spillover.

Effects of Flood

• Casualties: Human and livestock death due to drowning, serious injuries and outbreak of epidemics like diarrhea, cholera, jaundice or viral infections.

• Structural damage

• Material loss: Household articles including eatables, electronic goods, beds, clothes, furniture get submerged in water and get spoilt.

• Crop loss: Apart from the loss of human and cattle life, floods cause severe devastation of standing agricultural crops. Floods water spoils the stored food-grains or harvested crop.

• Drought

It is a situation when the mean annual rainfall is less than 75% of the normal rainfall. A severe drought situation is when the deficiency of rainfall exceeds 50% of the normal rainfall and moderate drought when the deficiency of rainfall is between 25-50% of the normal rainfall.

Drought in India

There is a history of drought in India. In India between year 1877 to 1987 (110 years) 23 droughts were faced by Indian population.

In general, about 16% area and 12% population is affected by drought every year according to data.

1.3 Man-made Disasters

Such type of disaster are the consequences of technological hazards. e.g. fires, transport accidents, industrial accidents, oil spills and nuclear explosions and radiation. War and deliberate attack are also in this category.

• Fires

Fires are events of burning something. They are often destructive taking up toll of life and property. It is observed that more people die in a fire than in a cyclone, earthquake, floods and other natural disasters combined. Fires are a great threat to forests and wildlife because they spread speedily and cause tremendous damage in a short time.

Causes

• Throwing burning matchsticks or cigarettes irresponsibility.

• Heating sources can cause fire in houses e.g. clothes may catch fire while cooking on kerosene stove or gas stove.

• Cooking accidents are a major cause of fire at home.

• Storage and transportation of inflammable material or explosive chemicals without proper precautions may cause fires.

• Road, rail and air traffic accidents

(i) Road:

Increased number of vehicles, violation of traffic rules, speeding, drunken driving and poor maintenance of vehicles as well as of roads are some of the main causes of road accidents.

(ii) Rail

The most common type of rail accident is derailment due to human error, sabotage or natural landslide in a hilly track, or fire. Rail accidents lead to large number of casualties and material damage. Indian Railways incur heavy loss due to such accidents every year.

(iii) Air Accidents

Air accidents may occur due to technical problems, fire, poor landing and take-off, weather conditions, hijacking, bombing etc.

• Nuclear War

In World War II, United States dropped nuclear weapons on Japanese cities-Hiroshima and Nagasaki on 6th and 9th August, 1945. This bombing killed at least 129000 people, it is only use of nuclear weapons in war history.

About 18 km height long ashes and fumes arises by nuclear bomb. The bomb dropped on Hiroshima was known as Little Boy, about 350000 population was live in Hiroshima at the time of bombing. Between 90000 to 166000 people are believed to have died from the bomb. The bomb dropped on Nagasaki was named as Fat man.

• Industrial Accidents

Industrial accidents can be due to explosion, fire and leakage of toxic or hazardous chemicals and lead to heavy loss of life and material. Leakage of chemicals and explosion may be due to human error, technological failure or geological hazards like earthquakes, flood etc. Fire in an industry may result from human error or electrical faults (short circuit).

• Bhopal Gas Tragedy

This was considered as the world's worst industrial disaster. Bhopal gas tragedy caused the single biggest air pollution tragedy. It occurred on the night of 2nd-3rd December, 1984 at Union Carbide India Limited, pesticide plant in Bhopal. There was leakage of Methyl isocyanate (MIC) gas and other gases resulting around 500000 people suffered in this incident. The Bhopal gas tragedy polluted drinking water, soils, tank and pond water and adversely affected fetus, newly born babies, pregnant woman, young and old people alike. It killed thousands of animals and micro-organisms.

• Noise Pollution

'Sound' is a necessary feature of our life. A low sound is pleasant where as a loud sound is disturbing and commonly referred as 'noise'. Noise is 'unpleasant and unwanted sound'. It can be recorded in Decibel meter. Different Decibel (dB) units for various activities,

• Total silence 0 dB
• A whisper 30 dB
• Normal conversation 60 dB
• Car horn 110 dB
• A rock concert/jet engine 120 dB
• A fire cracker/gunshot 140 dB
• Any sound above 85 dB can cause hearing loss.

• Green Muffler

With the help of this technique, we can control noise pollution by planting green plants, normally 4-5 rows of plants are grown near noisy areas like roadsides and industrial areas so that these trees can create some obstruction for noise to reach to residents.