NATURAL HAZARDS AND DISASTERS

• Change is the law of nature. It is a continuous
• process that goes on uninterruptedly involving
• phenomena, big and small, material and nonmaterial that make our physical and sociocultural environment. It is a process present
• everywhere with variations in terms of
• magnitude, intensity and scale.

Observe the environment you live in and

prepare a list of changes, which take

place over a long period of time and

those, which take place within a short

period of time. Do you know why some

changes are considered good and others

bad? Prepare a list of changes, which

you notice in your daily life and give

reasons why some of these are

considered good and others bad.

What is a Disaster?

“Disaster is an undesirable occurrence resulting from forces that are largely outside human control, strikes quickly with little or no warning, which causes or threatens serious disruption of life and property including death and injury to a large number of people, and requires therefore, mobilization of efforts in excess of that which are normally provided by statutory emergency services”.

Natural Hazards are elements of circumstances in the Natural environment that have the potential to cause harm to people or property or both

Some Natural Disasters Since 1948

• 1948 The Soviet Union (now Russia) Earthquakes 110,000
• 1949 China Floods 57,000
• 1954 China Floods 30,000
• 1965 East Pakistan (now Bangladesh) Tropical Cyclones 36,000
• 1968 Iran Earthquakes 30,000
• 1970 Peru Earthquakes 66,794
• 1970 East Pakistan (now Bangladesh) Tropical Cyclones 500,000
• 1971 India Tropical Cyclones 30,000
• 1976 China Earthquakes 700,000
• 1990 Iran Earthquakes 50,000
• 2004 Indonesia, Sri Lanka, India, etc. Tsunamis 500,000*
• 2005 Pakistan, India Earthquakes 70,000*
• 2011 Japan Tsunami 15,842*

Classification of Natural Disasters

• Atmospheric Terrestrial Aquatic Biological
• Blizzards Earthquakes Floods
• Thunderstorms Volcanic Eruptions Tidal Waves
• Lightning Landslides Ocean Currents
• Tornadoes Avalanches Storm Surge
• Tropical Cyclone Subsidence Tsunami
• Drought Soil Erosion
• Hailstorm
• Frost, Heat Wave or
• Loo.Cold Waves, etc.

Yokohama Strategy and International Decade for Natural Disaster Reduction (IDNDR)�Yokohama Strategy and Plan of Action for a Safer World

• (I) It will note that each country has the sovereign responsibility to protect its citizens from
• natural disasters;
• (ii) It will give priority attention to the developing countries, particularly the least developed,
• land-locked countries and small-island developing states;
• (iii) It will develop and strengthen national capacities and capabilities and, where appropriate,
• national legislation for natural and other disaster prevention, mitigation and preparedness,
• including the mobilisation of non-governmental organisations and participation of local
• communities;
• (iv) It will promote and strengthen sub-regional, regional and international cooperation in activities
• to prevent, reduce and mitigate natural and other disasters, with particular emphasis on:
• (a) human and institutional capacity-building and strengthening;
• (b) technology sharing: the collection, the dissemination and utilisation of information; and
• (c) mobilisation of resources.
• It also declared the decade 1990-2000 as the International Decade for Natural Disaster
• Reduction (IDNDR)

NATURAL DISASTERS AND HAZARDS IN INDIA

• It was discussed in one of the previous chapters that India is vast and diverse in terms of its physical and socio-cultural attributes. It is largely due to its vast geographical area, environmental diversities and cultural pluralities that scholars often described it using two meaningful adjectives like the ‘Indian-subcontinent’ and the ‘land of unity in diversity’. Its vastness in terms of natural attributes combined with its prolonged colonial past, continuing various forms of social discriminations and also equally large population have enhanced its vulnerability to natural disasters. These observations can also be illustrated by focussing on some of the major natural disasters in India.

Earthquakes

• Earthquakes are by far the most unpredictable and highly destructive of all the natural disasters.
• Earthquakes that are of tectonic origin have proved to be the most devastating and their area of influence is also quite large.
• e earthquake zones:
• (i) Very high damage risk zone
• (ii) High damage risk zone
• (iii) Moderate damage risk zone
• (iv) Low damage risk zone
• (v) Very low damage risk zone.

Socio-Environmental Consequences of Earthquakes

• The idea of an earthquake is often associated with fear and horror due to the scale, magnitude and suddenness at which it spreads disasters on the surface of the earth without discrimination. It becomes a calamity when it strikes the areas of high density of population. It not only damages and destroys the settlements, infrastructure, transport and communication network, industries and other developmental activities but also robs the population of their material and socio-cultural gains that they have preserved over generations.

Earthquake Hazard Mitigation

• (i) Establishing earthquake monitoring centres (seismological centres) for regular monitoring and fast dissemination of information among the people in the vulnerable areas. Use of Geographical Positioning System (GPS) can be of great help in monitoring the movement of tectonic plates.
• (ii) Preparing a vulnerability map of the country and dissemination of vulnerability risk information among the people and educating them about the ways and means minimizing the adverse impacts of disasters.
• (iii) Modifying the house types and building designs in the vulnerable areas and discouraging construction of high-rise buildings, large industrial establishments and big urban centers in such areas. (iv) Finally, making it mandatory to adopt earthquake-resistant designs and use light materials in major construction activities in the vulnerable areas.

Tropical Cyclone

• (i) Large and continuous supply of warm and moist air that can release enormous latent heat.
• (ii) Strong Coriolis force that can prevent filling of low pressure at the centre (absence of Coriolis force near the equator prohibits the formation of tropical cyclone between 0° -5° latitude).
• (iii) Unstable condition through the troposphere that creates local disturbances around which a cyclone develops.
• (iv) Finally, absence of strong vertical wind wedge, which disturbs the vertical transport of latent heat.

Floods

• the causes of floods are well-established.
• Floods are relatively slow in occurrences and often, occur in well-identified regions and within expected time in a year.
• Floods occur commonly when water in the form of surface run-off exceeds the carrying capacity of the river channels and streams and flows into the neighboring low-lying flood plains. At times, this even goes beyond the capacity of lakes and other inland water bodies in which they flow.
• Floods can also be caused due to a storm surge (in the coastal areas), high intensity rainfall for a considerably longer time period, melting of ice and snow, reduction in the infiltration rate and presence of eroded material in the water due to higher rate of soil erosion.

Droughts

• Drought is a complex phenomenon as it involves elements of meteorology like precipitation, evaporation, evapotranspiration, ground water, soil moisture, storage and surface run-off, agricultural practices, particularly the types of crops grown, socio-economic practices and ecological conditions

Types of Droughts

• Meteorological Drought : It is a situation when there is a prolonged period of inadequate rainfall marked with mal-distribution of the same over time and space.
• Agricultural Drought : It is also known as soil moisture drought, characterised by low soil moisture that is necessary to support the crops, thereby resulting in crop failures. Moreover, if an area has more than 30 per cent of its gross cropped area under irrigation, the area is excluded from the drought-prone category.
• Hydrological Drought : It results when the availability of water in different storages and reservoirs like aquifers, lakes, reservoirs, etc. falls below what the precipitation can replenish.
• Ecological Drought : When the productivity of a natural ecosystem fails due to shortage of water and as a consequence of ecological distress, damages are induced in the ecosystem.

Consequences of Drought

• Droughts have cascading effects on various other aspects of environment and society.
• Crop failure leading to scarcity of food grains (akal), fodder (trinkal), inadequate rainfall, resulting in shortage of water (jalkal), and often shortage in all the three (trikal) is most devastating.
• Large-scale death of cattle and other animals, migration of humans and livestock are the most common sight to be seen in the droughtaffected areas.
• Scarcity of water compels people to consume contaminated water resulting in spread of many waterborne diseases like gastro-enteritis, cholera, hepatitis, etc.

Landslides

• It happens due to landslide, which is the rapid sliding of large mass of bedrocks. Disasters due to landslides, are in general, far less dramatic than due to earthquakes, volcanic eruptions, tsunamis and cyclones but their impact on the natural environment and national economy is in no way less severe.

Landslide Vulnerability Zones

• Very High Vulnerability Zone :
• High Vulnerability Zone :
• Moderate to Low Vulnerability Zone :
• Other Areas :

DISASTER MANAGEMENT

• There are three stages involved in disaster mitigation and management:
• (i) Pre-disaster management involves generating data and information about the disasters, preparing vulnerability zoning maps and spreading awareness among the people about these. Apart from these, disaster planning, preparedness and preventive measures are other steps that need to be taken in the vulnerable areas.
• (ii) During disasters, rescue and relief operations such as evacuation, construction of shelters and relief camps, supplying of water, food, clothing and medical aids etc. should be done on an emergency basis.
• (iii) Post-disaster operations should involve rehabilitation and recovery of victims.