25 August 2015

Class 9th : Disaster Management

CBSE NCERT Class IX (9th) | Social Studies | Geography

Chapter 2  : Disaster Management

A disaster is a destructive event that occurs suddenly and involves loss of life and property.
Disasters can be of two types, natural and man-made.

Earthquakes, volcanic activity, tsunamis, floods, cyclones, landslides, avalanches and droughts are natural disasters and man has no control over them.

The man-made disasters are triggered by human beings. Some of the man-made disasters are: bomb explosions, terrorism, war or civil war, leakage of poisonous chemicals, breach in dams, air or water pollution, industrial accidents and epidemics.

Whether natural or man-made, these disasters hamper normal routine of the society and usually affect a large number of people. Disasters can also lead to huge loss of life and property.
When a disaster strikes a society, external help is usually needed in the form of aid to cope with its impact.

Disaster Management refers to the measures taken for the safety and protection of life and property from natural or man-made disasters.

This means being prepared for disasters, fighting disasters effectively, ensuring the safety of life during disasters and helping in rebuilding society after the disaster.


An earthquake is a sudden tremor or movement of the earth's crust, which usually originates at or below the surface. The outer layer of the earth is solid and is divided into many sections known as plates. These plates, float over the molten magma that flows beneath the earth’s crust. Many of the earthquakes occur on the edges of these plates along fault lines where the plates collide or try to slide past each other.

Apart from natural causes like the movement of the Earth's tectonic plates and volcanic eruptions, there are other man-made causes of earthquakes.

These include vibrations caused by big rocks falling down hills because of erosion, hollow parts of mines falling down due to dissolution of minerals by water and, in the present times, due to nuclear explosions.

The point of origin of the earthquake within the crust or mantle is called the seismic focus. Since the focus is often deep below the surface, the location of the earthquake is often referred to as the point on the surface of the earth, vertically above the seismic focus. This point is called the epicentre.

Scientists, who study earthquakes or seismology, measure earthquakes with a device called the seismometer; a device which also records is known as a seismograph. They use an instrument to measure the magnitude of the earthquake, called a ‘Richter Scale’.

Such under-sea earthquakes, give rise to giant waves called the tsunami, which cause great deal of destruction along the coasts.

Measures for protection against earthquakes:
  • Proper early warning system,
  • The information about earthquakes and their intensity should be shared with the public through radio, television and newspapers
  • Construction of buildings based on earthquake-resistant techniques
  • Construct buildings over pillars made of concrete and iron that are built deep in the ground
  • Water, ration, first-aid kits, radios, flash lights, battery, blankets, jackets and fire extinguishers should be stored in safe places.

Measure on the personal front:
  • Remain calm
  • If inside a building or a house, take cover under a solid surface like a table, or stand in the doorway
  • If one is outside, move to an open space away from trees, electric poles and buildings
  • Switch off the gas and electric supply in the house during a quake and do not use elevators
  • After the quake is over, the affected people should be given immediate medical help
  • People should be vaccinated to stop epidemics from spreading
  • Transport and communication facilities should be restored as soon as possible
  • Police and paramilitary forces should be deployed to protect properties which had to be abandoned from theft.

Volcanoes, Tsunamis and Cyclones

The earth is filled with molten magma at very high temperature. This molten magma is under enormous pressure and is on the constant lookout for an opening. When it finds one, all the molten rocks or lava, along with gases and steam flow out on to the earth’s surface. This is called a volcano.

When extraordinary levels of pressure develop within the earth, the lava and gases explode causing great destruction to the surrounding areas. Such violent eruptions are also accompanied by earthquakes.

Depending on their activity, there are three types of volcanoes: active, dormant and extinct. The active volcanoes erupt from time to time.

The dormant ones were active in the past, though they have not shown any activities for a long time.
The extinct ones on the other hand, do not have any recorded history of being active.

Earthquakes and volcanic eruptions cause a sudden disturbance at the base of the ocean, causing abrupt displacement of water. Such activities produce very high waves which are called Tsunamis, also known as killer waves or tidal waves.

A cyclone is an egg-shaped air formation that moves in the form of swirling winds. It has low air pressure at its centre but very high pressure at the surface. Since air moves from a region of high pressure to a region of low pressure, cyclones cause high winds and heavy rainfall. Since satellites help us in tracking the course of cyclones, the Indian Meteorological Department issues cyclone warnings in India. 

All About Floods

Flooding damages crops and contaminates sources of fresh water thus leading to shortage of food and drinking water.

Apart from damaging life and property, floods can also lead to epidemics.

Any flood is preceded by a threat period known as the Probability Period, which allows the authorities to issue warnings and plan evacuation.

Floods occur when land gets submerged under water due to various causes like excessive rain, overflowing rivers, increase in water in reservoirs, cyclones, tsunami, sea tides and melting of glaciers. Floods caused by cloud bursts, bursting of dams, or tsunamis are called flash floods. Any flood is preceded by a threat period known as the Probability Period. This allows the authorities to issue warnings and plan evacuation.

Artificial reservoirs should be built with sluice gates and sand bags should be used to block the flow of water. Low grounds or viaducts can be created to carry water in a certain direction or underground. Trees should be planted in the catchment areas to stop soil erosion.

Land Slides and AvalanchesDroughts

A drought occurs when there is acute shortage of water. Droughts that happen in India can be broadly divided into two categories. They are severe and general droughts.

Droughts are severe when rainfall in an area is below 50% of the average rainfall. When an area receives rainfall that is 25% less than the average rainfall, it is termed as a General Drought.

Based on their features and causes, droughts have been divided into three types. They are the Seasonal Drought, the Water Drought and the Agricultural Drought.

Seasonal Drought occurs when there’s little rain for a prolonged period. Lack of water in water resources such as rivers, lakes and ponds is called a Water Drought and lack of crops is called an Agricultural Drought.

The most common factor for a drought is scarce rain or no rain at all. Destruction of forests is another reason for droughts.

Over use of agricultural land is another cause of droughts. Less vegetation also leads to droughts. Depleting ground water level accompanied by the absence of rain also leads to a drought. We can store rain water to prevent droughts. We should plant more trees to avoid droughts. Nearly 35% of land should be earmarked as green belts.

Water supply to the agricultural fields in the parched regions can be increased by rainwater harvesting, canal irrigation and building contour bunds. Planting trees, harvesting rainwater, building dams to store excess rain water and crop insurance are some of the measures that we can take to cope with droughts.

Atomic, Biological and Chemical Disasters

Human disasters are man-made and involve elements of human intent, negligence, or the failure of a man-made system. Since weapons are created by man, disasters linked to it are called man-made disasters.

The government plays an important role in managing such attacks. It tries to solve the problem of the terrorist attacks  through discussions at the national and international levels. When the government receives intelligence about possible terror attacks, it issues warnings to the general public.

It also educates the people on a national scale about the dos and don’ts of avoiding as well as handling such attacks.

Another type of man-made disaster is biological disaster. Such disasters are caused by microorganisms that cause epidemics. These have spread due to man-made conditions. Most of these have been infectious diseases such as malaria, plague, diphtheria, tuberculosis and influenza. 

People can control the spread of these diseases by ensuring hygienic conditions and taking preventive measures. The government has taken a number of steps to contain the spread of these diseases such as fumigation to control the spread of the malarial mosquito.

In addition to biological disaster, chemical disaster is another man-made disaster. Chemical and radioactive leakages are also the result of human error and result in far reaching damages.

While natural disasters may be difficult to control, human disasters can be easily controlled if some stringent measures are taken up to prevent them on time.

General Human Disasters - 1

Fires disasters are mostly man-made and caused due to negligence and lack of maintenance. Fires can occur both indoors and outdoors. Fires are not restricted to buildings only. Forests are also prone to man-made fires which occur due to the carelessness of man.

It is possible to take measures to prevent fires and limit the damage caused by them.
  • Not keep inflammable matter at home and always keep a fire extinguisher handy.
  • Remember to switch off all the electrical gadgets as well as the gas before going outside.
  • Keep match boxes out of reach of children and restrain smoking in the house.
  • Call the fire brigade immediately so that not a single moment is wasted.
  • Try to crawl because smoke is always less near the floor.

The government has its own share of do’s and don’ts. It contributes to the safety of its people through stringent checks against violation of safety norms.

Disasters Involving Modes of Transport

Human disasters include accidents that occur while traveling by road, rail and air. Accidents mostly occur when rules are broken by people.

However, road accidents can be prevented by following traffic rules. The legal age to start driving is eighteen.

Once you get your license, strictly follow the rules which were ingrained in you during the training. Another mode of transport in India is the Indian Railways, which has the largest rail network in Asia and the second largest in the world.

Train accidents are usually caused by derailment, signal failure or fires caused by inflammable material. One should always pay attention to signals, and look out while crossing unmanned level crossings. Air travel has gained popularity in recent years in India due to the introduction of low cost carriers. Plane accidents occur due to human error as well as extreme climactic conditions.

Some human-made air disasters can be caused by poor maintenance of the aircraft, fire outbreaks and tired or inexperienced pilots. There are also eventualities like hijacking.

Disasters involving road, rail and air are usually caused by human errors and can be easily avoided by following rules and regulations.

Stages of Disaster Management

Disaster management prepares us to deal with such situations by preventing any calamity, minimising the effects, and taking timely action for normalising the situation.   

Disaster Management is a chain of activities carried out before, during and after the disaster occurs.

To effectively deal with disaster in all its stages, disaster management is broken down in to four important stages. These are advance preparation, relief to the victims, restoration of normalcy and prevention plan for the future.

Role of Administration

On the national level, the role of the administration is to initiate rescue and relief operations depending on the gravity of the disaster.

At the Central level, the Government has nominated nodal ministries to manage various types of disasters which help in streamlining rescue operations.

There is a National calamity management committee which is presided over by the Cabinet Secretary. The calamity management group also deals with Disaster Management responsibilities and functions under the Central Aid Commissioner.

In addition to these administrative committees, technical support is provided by organizations like the Central Weather Science Department (for cyclone and earthquake), Defence Research and Development Organisation and the Civil Defence General Director. At the State Level, a committee under the Chief Minister or the Chief Secretary views and takes care of relief operations.

At the district level, the District Magistrate and the District Administration are responsible for executing relief operations.

The Block Development Officer manages the operations at the block level in case of any disaster. At the village level, the Sarpanch of a village heads the disaster management committee and assists the various organizations working in the field.

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