Study Material Natural Hazards

8/22/2019 Study Material Natural Hazards

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Top Careers & YouGeneral Studies

Natural Hazards and Disasters1

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Natural Hazards and Disasters

A natural hazard is a threat of a naturally occurring event (for example floods, tornadoes, hurricanes,

volcanic eruptions, earthquakes, heatwaves, or landslides) that will have a negative effect on people or the

environment. A natural disaster is the effect of the earth's natural hazards. Many natural hazards are

interrelated, e.g. earthquakes can cause tsunamis and drought can lead directly to famine or population

displacement. It is possible that some natural hazards are intertermporally correlated, as well. A concrete

example of the division between a natural hazard and a natural disaster is that the 1906 San Francisco

earthquake was a disaster, whereas earthquakes are a hazard.

A natural disaster can lead to financial, environmental or human losses. The resulting loss depends on the

vulnerability of the affected population to resist the hazard, also called their resilience. If these disasters

continue it would be a great danger for the earth. This understanding is concentrated in the formulation:

"disasters occur when hazards meet vulnerability." Thus a natural hazard will not result in a natural disaster in

areas without vulnerability, e.g. strong earthquakes in uninhabited areas. The term naturalhas consequently

been disputed because the events simply are not hazards or disasters without human involvement.

Types of Natural Disaster: There are many types of Natural Disaster in this amazing world. They can be

grouped as six major types. They are explained below with some examples:

1) Land Movement Disasters

i) Earthquakes

ii) Avalanches

iii) Lahars

iv) Volcanic Eruptions

2) Water Disasters

i) Floods

ii) Tsunami

3) Weather Disasters

i) Cyclonic Storms

ii) Blizzards

iii) Droughts

4) Disasters caused by Fire

i) Forest Fire

5) Health and Diseases

i) Epidemic

ii) Famine

6) Space Disasters

i) Supernovae and Hypernovae

ii) Solar Flares

iii) Gamma Ray Bursts


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Natural disasters in India

Natural disasters in India, many of them related to the climate of India, cause massive losses of Indian life

and property. Droughts, flash floods, cyclones, avalanches, landslides brought on by torrential rains, and

snowstorms pose the greatest threats. Other dangers include frequent summer dust storms, which usually

track from north to south; they cause extensive property damage in North India and deposit large amounts of

dust from arid regions. Hail is also common in parts of India, causing severe damage to standing crops such

as rice and wheat.

Earthquakes: Earthquakes take place due to sudden release of energy through the earth's crust in the form

of seismic waves. Seismic zonation map shows that India is highly vulnerable for earthquake hazards. India

has witnessed more than 650 earthquakes of Magnitude >5 during the last hundred years and earthquake

disaster is increasing alarmingly here.

The occurrence of earthquakes can be explained with the concept of "Plate Tectonics" Based on this, three

broad categories of earthquakes can be recognized: 1) those occurring at the subduction/collision zones

(Inter-plates), 2) those at mid-oceanic ridges and 3) those at intra-plates. Seismic events in India mainly

belong to the first category though a few third category events are also known. Earthquake events are

reported from the Himalayan mountain range including Andaman and Nicobar Islands, Indo-Gangetic plain

and Peninsular region of India.

Subduction/collision earthquakes in India occur in the Himalayan Frontal Arc (HFA). This arc is about 2500km

long and extends from Kashmir in the west to Assam in the east. In constitutes the central part of the Alpine

seismic belt and is one of the most seismically active regions in the world. The Indian plate came into

existence after initial rifting of the southern Gondwanaland in late Triassic period and subsequent drifting in

mid-Jurassic to late Cretaceous time. The force responsible for this drifting came from the spreading of the

Arabian Sea on either side of the Carisberg ridge. It eventually collided with the Eurasian plate in Middle

Eocene after NNE drifting along counter clockwise path. The NNE ward movement of the Indian plate caused

continental collision with the rates of convergence varying from 44 - 66mm per year. This led to the creation of

Himalayan mountain range. The present day seismicity of this is due to continued collision between the Indian

and the Eurasian plates. The important earthquakes that have visited HFA are tabulated below:

Place Year Magnitude Casualty

Kangra Valley April 4, 1905 8.6 >20,000

Bihar-Nepal border January 1, 1934 8.4 >10,653

Quetta May 30, 1935 7.6 About 30,000

North Bihar 1988 6.5 1000 Approx.

Uttar Kashi October 20, 1991 6.6 >2,000

Chamoli March 29, 1999 6.8 >150

Hindukush November 11, 1999 6.2 no death reported


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This seismic hazard status of Peninsular India, which was once considered as a stable region, has increased

due to the occurrence of damaging earthquakes. The recurrence intervals of these are, however, larger than

those of the HFA and their magnitude is also lesser. These belong to intra-plate category of earthquakes. The

following are the important events that have rocked the Peninsular India.

Place Year Magnitude Casualty

Kutch June 16, 1819 8.5 No record

Jabalpur June 2, 1927 6.5 ------

Indore March 14, 1938 6.3 ------

Bhadrachalam April 14, 1969 6.0 ------

Koyna December 10, 1967 6.7 >200

Killari (Latur) September 30, 1993 6.3 >10,000

Jabalpur May 22, 1997 6.0 >55

Koyna event is a classic example of earthquake activity triggered by reservoir. Seismicity at Koyna has close

correlation with the filling cycles of the Koyna reservoir. The most puzzling event in the Peninsular India is,

however, the Killari earthquake, which occurred in the typical rural setting. This event was least expected from

the tectonic consideration, as it is located in the Deccan Trap covered stable Indian shield. There is no record

of any historical earthquake in this region. This has been considered as the most devastating SCR (Stable

Continental Region) event in the world. Jabalpur event, which occurred in the urban centre, though moderate,

is an important one because it is the first major earthquake in India to be recorded by the newly establishedbroadband digital station in the shield region. Moreover, its spatial association with the Narmada Son

lineament has triggered a lot of interest from the seismo-tectonic point of view.

Earthquake Hazards In The North Eastern Region

Northeastern region of India lies at the junction of the Himalayan arc to the north and the Burmese arc to the

east and is one of the six most seismically active regions of the world. The other five regions are Mexico,

Japan, Taiwan, Turkey and California. Eighteen large earthquakes with magnitude >7 occurred in this region

during the last hundred years. High seismic activity in the northeastern region may be attributed to the

collision tectonics in the north (Himalayan arc) and subduction tectonics in the east (Burmese arc). The

Syntaxis Zone (The Mishmi Hills Block) is the meeting place of the Himalayan and Burmese arcs and is

another tectonic domain in the region. The Main Central Thrust (MCT) and the Main Boundary Thrust (MBT)are the two major crystal discontinuities in the Himalayan arc of the Northeastern region. In the Burmese arc,

the structural trend of the Indo-Myanmar Ranges (IMR) swing from the NE-SW in the Naga Hills to N-S along

the Arakan Yoma and Chin Hills. Naga Thrust is the prominent discontinuity in the north. It connects the Tapu

Thrust to the south and Dauki Fault to the east. This fold belt appears to be continuous with the Andaman-

Nicobar ridge to the south. The Mishmi Thrust and the Lohit Thrust are the major discontinuities identified in

the Syntaxis Zone. The following is the list of important earthquake events in this region:


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Has the earthquake frequency increased?

Seismologists seem not believe that there is upheaval in the occurrence of earthquakes. However, these often

occur in uninhabited areas or virtually uninhabited areas. Unfortunately, these have now hit thickly populated

areas and killed thousands of people. This does not mean that the earthquake frequency has increased.

Increase in the loss of life and property damage is not due to increase in number and strength of earthquake

frequency but for the rapidly increasing vulnerability of human civilization to these hazards. This can be

understood by the fact that Kangra event of 1905 (Ma=8.6) and Bihar-Napal of 1934 (Ma=8.4) killed

respectively about 20,000 and 10,653 people whereas 1897 and 1950 events of the northeast (Ma=8.7 each)

could kill only about 1542 and 1520 people. This is because Kangra and Bihar-Nepal events struck densely

populated areas of Indo-Gangetic plain whereas the northeastern region was sparsely populated in 1897 and

1950. Population concentration and physical resources have increased many times in this region since the

last great event. Therefore, if the earthquake of matching magnitude visits the region now, the devastation

would be enormous.

Earthquake Prediction

Research on earthquake prediction started since early sixties. Intensive work is going on all over the world in

this regard involving expenditure of billions of dollars. The precise prediction of seismic events remains

elusive and unattainable goal as yet in spite of these efforts. According to R.R. Kelkar, Director General of

Indian Meteorological Department (IMD), "Earthquake cannot be predicted by anyone, anywhere, in any

country. This is a scientific truth". But seismologists continue their efforts in the hope of a major breakthrough

in prediction technology in the near future. The seismologists are, however, in a position to indicate the

possibility of recurrence of earthquakes in potentially large areas based on palaeo-seismicity, micro seismic

activities and precursors.

It has been found that earthquakes are generally, but not necessarily, preceded by some signals like ground

tilting, foreshocks, change in ground water levels, variations in the discharge of springs, anomalous oil flow

from the producing wells, enhance emanations of radon and unusual animal behaviour. Monitoring and

analysing animal behaviour can help to forecast earthquakes.

Earthquake Hazard Zonation, Risk Evaluation And Mitigation

The importance of seismological studies lies in the fact that information generated can be used to mitigate the

earthquake hazards. Preparation of seismo-tectonic/seismic zonation maps is the first step in this direction.

The basic data required for the preparation of these maps are (i) A carefully compiled earthquake catalogue

incorporating details about magnitude, location of epicenter, depth of focus etc., (ii) Delineation of seismic

source zones from all possible sources like recurrence relation, tectono-geological consideration,

palaeoseismicity etc., (iii) Estimation of upper bound magnitude through statistical procedure, cumulative

seismic energy release, active fault length etc. and (iv) Attenuation of ground shaking for better results.

Seismic micro-zonation is recommended for better result. These maps give an idea about the possibility of

occurrence of earthquakes in the region and are very useful for evaluating the risk involved before designing

and constructing the heavy engineering structures like dam, bridges, flyovers and large towers etc. These are

also useful for planning human settlements that would remain safe during the occurrence of an earthquake.

Seismic risk evaluation is also possible from these maps.


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Earthquake Resistant Structures

It is necessary to design and construct earthquake resistant dwellings in the seismic prone zones. The

principles of a seismic design should be kept in mind in this regard. The important earthquake resistant

features which are recommended in the latest BIS codes (IS 13828:1993) should be followed. Normally

houses are built to withstand vertical load only and as a result they collapse when subjected to horizontal

stresses produced by earthquake waves. The main requirements for preventing the collapse are a lateral load

carrying system of enough residual capacity to safely resist lateral forces, a monolithic roof with sufficient in-

place rigidity and a strong and durable vertical load carrying system. It is said that the buildings made after

1981 basically had no damage due to Kobe event of 1995 in Japan because these fulfilled earthquake

standards of construction. Besides, good quality construction materials should be used.

Awareness Campaign

Awareness campaign needs to be launched to educate the people about the disastrous effects of earthquakes

and to prepare them to face these in a better way. Prevention and mitigation begins with the information.

Moreover, public education and community participation is the key to the success of the implementation of

reduction and mitigation programmes.

A large number of specialised as well as popular articles have been written about earthquakes in research

journals and conference proceedings, which are not available to common man. The newspapers and

magazines usually do not show interest in publishing articles about mitigation and hazard reduction, however,

they give extensive coverage after earthquake takes place. Information and popular articles should be written

in simple language and be made readily available to common man. There has to be a close interaction

between the seismologists and the administrators, which would greatly help the execution of seismic

mitigation programmes. Earthquake related curricula should be introduced in the school stage of education

itself. Audio-visual programmes, preferably in the local languages have to be prepared and made available to

the public. Voluntary organisation and college students may be approached to take up the responsibility of

awareness campaign.


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Tsunami

A tsunami is a series of water waves caused by the displacement of a large volume of a body of water,

typically an ocean or a large lake. Earthquakes, volcanic eruptions and other underwater explosions (including

detonations of underwater nuclear devices), landslides, glacier calvings, meteorite impacts and other

disturbances above or below water all have the potential to generate a tsunami.

The principal generation mechanism (or cause) of a tsunami is the displacement of a substantial volume of

water or perturbation of the sea. This displacement of water is usually attributed to earthquakes, landslides,

volcanic eruptions, glacier calvings or more rarely by meteorites and nuclear tests. The waves formed in this

way are then sustained by gravity. Tides do not play any part in the generation of tsunamis.

Natural Hazard Map - India


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Tsunamis cause damage by two mechanisms: the smashing force of a wall of water travelling at high speed,

and the destructive power of a large volume of water draining off the land and carrying all with it, even if the

wave did not look large.

Although tsunami's impact is only limited to the coastal areas, it can be enormously destructive. It can It can

also affect the entire ocean's basins. In 2004, the Indian Ocean tsunami was marked as the deadliest natural

calamities in the history of human. During this disaster, 14 countries having Indian Ocean as their border

witnessed more than 2, 30,000 people killed. The first tsunami to struck India was back in December 31,

1881. However, the government of India indicated that around 11,000 people died and more than 5,000 were

missing and were assumed dead by the Home Affairs Ministry. An estimation points out that about 380,000

Indians displaced by this tsunami. It is expected that reconstruction of these affected places would cost over

1.2 billion dollars from the World Bank.

On December 26, 2004, most of the countries located around the Indian Ocean and Bay of Bengal were

struck by tsunami. During this time, the Richter scale measured the earthquake at 8.9 with an epicentre near

Sumatra's west coast in Indonesia. The Andaman Island was said to be extensively damaged due to this

tsunami. The regions affected the most by tsunami were the Andaman and Nicobar Islands and south-eastern

coast.

India is the third country to be severely affected with tsunami after Sri lanka and Indonesia. Indian states

affected by tsunami were Tamil Nadu, Puducherry, Kerala, Andhra Pradesh, and Andaman and Nicobar

Island.

Tsunami Mitigation and Management

In India, Indian Nation Centre For Ocean Information Services (INCOIS) has a data warehouse of ocean

related information gathered from various institutions in India, which are involved in Marine Data Collection,

Ocean Observation and Ocean/Atmospheric sciences. INCOIS will then translate it into deliverable products

to a range of users - Fishing community, State Fishery Department Officers, Planning Commission, Ports and

Harbours, Shipping Industry, Navy, Coast Guards, NHO Central Pollution Control Board, MHR - Ministry of

HR etc

An Early Warning System is imperative for the Indian Ocean to mitigate the loss of life and property due to

Tsunamis and Storm Surges. The Indian Tsunami Early Warning System incorporates the needs of storm

surge forecast too. The System design is based on end-to-end principle encompassing:

Setting up a dedicated Tsunami Warning Centre(include Storm Surge) in India and operating it on

24x7 basis for generation of timely advisories and Dissemination

Near-real time determination of earthquake parameters in the two known Tsunamigenic zones of

Indian Ocean region.

Establishing a comprehensive real time Ocean observational network comprising Bottom PressureRecorders around the two Tsunamigenic zones, Tide Gauges, Radar-based Coastal Monitoring

Stations etc.

Developing numerical models for Tsunami and Storm Surges with all associated data inputs

Generating Coastal inundation and Vulnerability maps

Capacity building, training, education of all stakeholders

International connectivity.


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Indian Initiative for the Dual-use Early Warning System covers the two known Tsunamigenic zones that affect

Indian Ocean region.It is an end-to-end system that is scientifically and technically sound.It is comprehensive

and covers the required observations, modeling, data communication, warning centre, capacity building

Droughts

Droughts can be of three kinds:-

(i) Meteorological drought: This happens when the actual rainfall in an area is significantly less than the

climatological mean of that area. The country as a whole may have a normal monsoon, but different

meteorological districts and sub-divisions can have below normal rainfall. The rainfall categories for

smaller areas are defined by their deviation from a meteorological area's normal rainfall

Excess: 20 per cent or more above normal

Normal: 19 per cent above normal - 19 per cent below normal

Deficient: 20 per cent below normal - 59 per cent below normal

Scanty: 60 per cent or more below normal

(ii) Hydrological drought: A marked depletion of surface water causing very low stream flow and drying of

lakes, rivers and reservoirs

(iii) Agricultural drought: Inadequate soil moisture resulting in acute crop stress and fall in agricultural

productivity

Drought in India has resulted in tens of millions of deaths over the course of the 18th, 19th, and 20th

centuries. Indian agriculture is heavily dependent on the climate of India: a favorable southwest summer

monsoon is critical in securing water for irrigating Indian crops. In some parts of India, the failure of the

monsoons result in water shortages, resulting in below-average crop yields. This is particularly true of major

drought-prone regions such as southern and eastern Maharashtra, northern Karnataka, Andhra Pradesh,

Orissa, Gujarat, and Rajasthan. The World Record of Drought was in 2000 in Rajasthan, India.

Impact of El Nio

All such episodes of severe drought correlate with El Nio-Southern Oscillation (ENSO) events. El Nio-

related droughts have also been implicated in periodic declines in Indian agricultural output. Nevertheless,

ENSO events that have coincided with abnormally high sea surfaces temperatures in the Indian Oceanin

one instance during 1997 and 1998 by up to 3 C (5 F)have resulted in increased oceanic evaporation,

resulting in unusually wet weather across India. Such anomalies have occurred during a sustained warm spell

that began in the 1990s. A contrasting phenomenon is that, instead of the usual high pressure air mass over

the southern Indian Ocean, an ENSO-related oceanic low pressure convergence center forms; it then

continually pulls dry air from Central Asia, desiccating India during what should have been the humid summer

monsoon season. This reversed air flow causes India's droughts. The extent that an ENSO event raises sea

surface temperatures in the central Pacific Ocean influences the degree of drought.

Floods

Floods in India destroy and devastate the lives of the citizens in most of the affected regions. Moreover, many

properties and materials are destroyed along with deaths of humans, cattle and other animals. Floods in India

are mainly caused due to rainfall in a large area during the monsoon periods. Flood destructions have always

brought misery to numerous people, especially in the rural areas. When a large portion of the country remains

flooded for a week with few decimeters deep water, it affects the normal life of the people badly. A large

number of houses made of mud collapse; it also tarnishes the stored food grains and fodder and devastates

the standing crops. Railway tracks and roads are breached at several places. Further more, traffic is


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suspended for a number of days on certain affected areas. Huge financial losses are incurred by the railways

and bus transport companies. Floods badly affect the water supply by damaging the sewage plants. It results

in the outbreak of serious epidemics, specifically malaria and cholera. At that time, acute scarcity of water also

arises.

Causes of Floods in India

The areas in the nation which are subjected to serious floods are basically in the plains of northern India. It is

also estimated that more than 90% harm of property and crops is caused by the floods in the plains of this

region of the country. Lower Tapti and Lower Narmada valleys, the deltas of the Godavari River, the Krishna

River and the Mahanadi River are flooded from time to time. It is stated that the major cause of f loods is heavy

downpour of rain in the catchments areas of rivers and in the poorly drained areas. In plains of few states like

Punjab and Haryana, rivers overflow their banks and inundate the adjoining low-level areas. In India, unusual

heavy rains occur during the summer-monsoon rainy season. The chances of flood havoc are also high in

waterlogged and poorly drained areas. In India, Punjab- Haryana plains are one of the worst flood affected

areas and it accounts for more than 15% of the total losses of the country.

Further, in the plain regions of Uttar Pradesh and Bihar, huge areas are inundated where Ganga River

receives its tributaries. Near the convergence of river Ganga with its tributaries, free flow of the water is

interrupted when Ganga itself is in floods. As a result of the congestion of the water in these tributaries, the

water level raises at times causing floods. Owing to such floods, the cultivated lands face total destruction.

Huge fertile lands become wastelands after the deposition of course sands. Assam valley is one such fertile

belt that has been seriously affected by flood havocs. In Assam, heavy rainfall (more than 200 cm) in the rainy

season is the principal reason of floods in Assam Valley. Interestingly, earthquakes that are not very

uncommon in this north-eastern state also cause floods in a number of ways. The shift in the level of land also

causes the change of the course of the river. Southern part of West Bengal also suffers heavy floods that are

caused by poor drainage system and heavy rains. Moreover, floods are a regular feature in the coastal

lowlands of Orissa.

Major causes of floods are deforested catchments area of the rivers and secondly, the offshore bars that

obstruct the mouths of the rivers, eventually obstructing the free flow of water into the ocean. The deltas of

Godavari River and Krishna River have also suffered floods in the country. Comparatively, in the plateau of

peninsular India floods are far less destructive. Further, they are far less recurrent than in other parts of the

country.


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Map of India Flood Prone Areas

Effects of Floods in India

Floods in India also have a drastic effect on the agricultural sphere. Occasionally water remains standing over

large areas for a long span of time hampering the Rabi crop plantation. Destruction of Kharif crop as well as

Rabi crop in various places result in dearth conditions that may quite serious similar to that caused by severe

droughts. Moreover, roadways and infrastructure is damaged, properties are destroyed along with numerous

loss of lives. In the recent years, the most devastating floods in India have occurred in Assam from 1998, in

the city of Mumbai in 2005, flood in 2008 which mostly affected Maharashtra, Andhra Pradesh and Bihar;

flooding in South India in 2009 and the Leh floods in 2010 in the largest town of Ladakh. Several people lost


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their lives in the 2010 Leh floods which occurred as a result of cloudburst and heavy rainfall which triggered

flash floods and mudslides.

Government of India spends a huge some of money on relief and rehabilitation for the people every year.

Several flood control measures have been taken in the country such as construction of storage dams, making

of proper drainage channels etc.

Cyclones

Cyclones are caused by atmospheric disturbances around a low-pressure area distinguished by swift and

often destructive air circulation. They are usually accompanied by violent storms and bad weather. The air

circulates inward in an anticlockwise direction in the northern hemisphere and clockwise in the southern

hemisphere. Cyclones are classified as: (i) extra tropical cyclones (also called temperate cyclones);

and (ii) tropical cyclones.

Indian Context

The Indian subcontinent is one of the worst affected regions in the world. The subcontinent with a long

coastline of 8041 kilometre is exposed to nearly 10 per cent of the worlds tropical cyclones. Of these, the

majority have their initial genesis over the Bay of Bengal and strike the east coast of India. On an average,

five to six tropical cyclones form every year, of which two or three could be severe. More cyclones occur in the

Bay of Bengal than the Arabian Sea and the ratio is approximately 4:1. Cyclones occur frequently on both the

coasts (The west coast Arabian Sea; and the east coast Bay of Bengal). An analysis of the frequency of

cyclones on the east and west coasts of India between 1891 and 1990 shows that nearly 262 cyclones

occurred (92 severe) in a 50 km wide strip on the east coast. Less severe cyclonic activity has been noticed

on the west coast, with 33 cyclones occurringin the same period, out of which 19 of these were severe.

Tropical cyclones occur in the months of May-June and October-November. The cyclones of severe intensity

and frequency in the north Indian Ocean are bi-modal in character, with their primary peak in November and

secondary peak in May. The disaster potential is particularly high at the time of landfall in the north Indian

Ocean (Bay of Bengal and the Arabian Sea) due to the accompanying destructive wind, storm surges and

torrential rainfall. Of these, storm surges are the greatest killers of a cyclone, by which sea water inundates

low lying areas of coastal regions and causes heavy floods, erodes beaches and embankments, destroys

vegetation and reduces soil fertility.

Cyclones vary in diameter from 50 to 320 km but their effects dominate thousands of square kilometers of

ocean surface and the lower atmosphere. The perimeter may measure 1,000 km but the powerhouse is

located within the 100-km radius. Nearer the eye, winds may hit 320 kmph. Thus tropical cyclones,

characterized by destructive winds, torrential rainfall and storm surges disrupt normal life with accompanying

the phenomena of floods due to the exceptional level of rainfall and storm surge inundation into inland areas.

Cyclones are characterized by their devastating potential to damage structures, viz. houses; lifeline

infrastructure-power and communication towers; hospitals; food storage facilities; roads, bridges and culverts;

crops etc. The most fatalities come from storm surges and the torrential rain flooding the lowland areas of the

coastal territories.

Disaster Management in India

Disaster is a very common phenomenon to the human society. It has been experienced by them since time

immemorial. Though its form may be varied, it has been a challenge for society across castes, creeds,

communities and countries. The latest development which has been discovered in the World Disaster Reports

recently is that the disasters have increased in frequency and intensity.


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People are becoming more and more vulnerable to disasters of all types, including earthquake, flood,

cyclones, landslides, droughts, accidents, plane crash, forests fire, etc. With the technological advancements

and progress, the force of disasters is also changing. When they occur they surpass all preparedness and

eagerness of society and pose bigger challenge to them. This is quite true in case of both developed and

developing countries. The floods in UK, France, and heat wave in Europe, particularly in France in 2003,

claimed more than 35000 lives. In the year 2006, America had to face bigger disaster in the form of tornadoes

and other cyclones. They caused great loss of lives and property. All these are sufficient to prove that

technological mechanisms are inadequate.

There is a direct correlation between higher human development and higher preparedness. The countries

which have lesser human development are more vulnerable to risks of disasters and damage. Of all the

disasters, floods are the most common followed by wind storms, droughts and earthquakes. But the drought is

the deadliest disaster which accounts for 48 per cent of all deaths from natural disasters. The highest

numbers of people die from disasters in Asia. India, China and Bangladesh are the worst affected countries by

flood. Besides the natural disasters, transport accidents and technological disasters are also faced by the

developing countries.

India, due to its geographical locations and geological formations, is a highly disaster prone country. Its long

coastline, snowclad high peaks, high mountain ranges, the perennial rivers in the north all combine to add to

this problem. India, which has only two per cent the total geographical area, has to support 16 per cent of total

world population. Naturally, there is a tremendous pressure on the natural resources, which directly or

indirectly lead to the occurrence of disasters, namely floods, droughts, landslides, earthquakes, etc.

Like human population, India has to support large cattle population, which also heavily depends on biomass

and graze into forest area. The forest cover with more than 0.4 densities is 12 per cent of the land area,

though forest, at present, is 23 per cent. Due to overgrazing the quality of soil is also degrading resulting in

soil erosion, silting of rivers, and removal of fertile soil and heavy silting of cultivable land. We see heavy

rainfall during the monsoon, sometimes 100 cm rain in 36 hours or getting the whole monsoon rain two to

three days like the ones in Maharashtra, Gujarat, and Kolkata. From the region wise analysis, it is clear that

northern region of India is faced with problems of avalanches, landslides, floods, drought and earthquakes

because this region fall under the seismic zones III to V.

The Eastern region is confronted with the heavy floods in the perennial rivers of Brahmaputra, Ganga, etc.

Drought, heat wave, hailstorm, cyclone, heavy wind and earthquake are also common in this region. The

Northeastern region faces the natural disaster in the form of flood, landslides, wind outrage, earthquake as

most of this part of the country comes under the seismic zones IV and V.

The Western region is widely known for severe drought, wind erosion of land and soil, flood and cyclone. This

area is also prone to earthquakes. The Southern region, particularly the coastal region is vulnerable to

cyclones, sea erosion, tsunami, landslides. The islands of Andaman & Nicobar and Lakshadweep are

confronted with the problems of sea erosion and tsunami. Indian coastal areas faced some of the severest

cyclones both in Eastern coast and Western coast. One of the natural disasters, namely the volcanoes is in

the barren island in Andaman group of islands which periodically become active.


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In recent times, it was active in 2005. Among all the disasters, tsunami is the latest phenomena, which was

never seen or heard earlier. Due to having no adequate warning system, it devastated a large portion of

coastal region of Tamil Nadu, Kerala and Andhra Pradesh besides Andaman & Nicobar Islands and claimed a

large number of innocent lives and destroyed property worth crores of rupees.

India has faced a number of disasters, ranging from flood, earthquakes, cyclones, tsunami, drought,

landslides. A few recent disasters faced by India include Uttar Kasha earthquake in UP in 1991, Later

earthquake in Maharashtra in 1993, Chama earthquake in Gujarat, super cyclone in Orissa in 1999, Buhl

earthquake in Gujarat in 2001, Tsunami in 2004 and Mumbai-Gujarat flood in 2005. Besides, India has a bad

experience of technology-related tragedy in the form of gas tragedy in Bhopal in 1984. India also faced the

problem of Plague in Gujarat.

The direct or indirect impacts of disasters, either natural or technological, are always damage, destruction and

death. They cause loss of life of both men and animals and properties as well. At the occurrence of disaster,

everything goes haywire in view of the destruction of lifeline support systems, namely communication, power

supply, water supply, drainage, etc. In this situation the health care and hospitals are also put under severe

stress. Commercial and economic activities are badly affected. Life almost comes to a standstill.

The impact is almost same, in case of man-made disasters like riots. The worst affected group is the poor

sections of society, who are daily wage-earner. They are the most vulnerable and they suffer the loss of their

livelihood. The psychological traumas caused by the disasters are sometimes so severe that they span the

whole of life of the victim. Besides other rehabilitation works, psychological rehabilitation is of great

importance.

In some natural disasters like cyclones, tsunami and earthquake, it is the building structure which becomes

the cause of destruction and death. It is due to this fact that in building construction, building codes are not

followed property. In developing countries only 30 per cent of built infrastructures are constructed as per the

building codes, while semi-permanent and other buildings do not follow the plan. Besides, the low quality of

building material, liberal flouting and lack of master plan are some of the major constraints in this regard.

The UNDA with Government of India has jointly prepared an action plan for cities and towns vulnerable to

earthquakes. The need in the vulnerable zones is that the existing buildings be technically assessed and

evaluated and individual owners and group housing authorities should be informed about the weaknesses in

their construction. Presently, in India, it is estimated that around 10 lakhs buildings which are constructed

every year, an equal number of them get damaged as a result of disasters. It is required that a monitoring

mechanism should be set up in disaster prone areas and it must act in proper coordination with the concerned

to ensure fulfillment of building codes.

Disaster is a state subject in India; it is, therefore, the responsibility of the state to provide every kind of

support and assistance to the victim. The Central Government has a facilitating role. It, with proper

coordination with various ministries, extends all required support and helps to the states, namely defence

services, air dropping, rescuing, searching, transport of relief goods, availability of rail and ferry services,

health personnel and medical support, etc. In the State, the Relief Commissioner or Disaster Management

Secretary is the specific authority responsible for handling and management of the disaster.


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At the state level there is a State Level Disaster Management Committee consisting of senior secretaries of

various departments and representatives of the NGOs. At national level, there is a Crisis Management

Committee headed by the Cabinet Secretary and secretaries from major departments of governments. In

1999 a high powered Committee on Disaster Management was set up by the Government of India to look into

the existing disaster management system in the country and to suggest measures to improve it. Besides, a

Calamity Relief Fund has been constituted with contribution in ratio 3: 1 between the Centre and the

respective State Government. The Eleventh Finance Commission has recommended nearly Rs. 11,000 crore

for the period spread over five years, while the Twelfth Finance Commission has also recommended a Rs

23,000 crore assistance for the states.

Rehabilitation is an integral part of disaster management. When disasters occur administrative measures are

terribly inadequate and perhaps this is the most difficult period for a victim. The role of administration does not

end with end of disasters. In fact its effort and commitment get more complex. It requires proper coordination

among various agencies. In this context it is very important to note that disasters are non-routine events that

require non-routine response. Government cannot rely on normal procedures to implement appropriate

responses- the rescue teams require learning special skills, technologies and attitudes in dealing with

disasters.

Disaster Management has assumed great importance in recent times. To handle the situation efficiently, we

need to be well-equipped with latest technologies. It cannot avert the situation, but can mitigate its impacts.

Documents

Study Material Natural Hazards