• Soil: Soil is a thin surface layer of the earth mixed with minerals and vegetative materials. Agricultural activities and growth of plants and trees depend on the fertility of soil
• Formation of the Soil: Formation of soil is a very long process. Due to the heat of the sun, the force of winds and rains break big rocks into tiny pieces which came together to form soil. The growth of vegetation depends on the type of soil.

                                Sunlight                                                  Living creatures    

                                                               Wind                    Rain               

• Major types of soil: Alluvial soil, Black soil, Red soil, Laterite soil, Forest and hilly soil and Desert soil are the important types of soil found in India. It takes 1000 years for a centimeter of soil to be formed.

• Dwarf Planets :Pluto, Charons, Ceres, Eris were newly Grouped as Dwarf Planets in the Year 2006.They are very small in Size .Their size is smaller than our moon, so it is called as Dwarf Planets.
• Leap Year: The Earth does not exactly take 365 days to complete one revolution around the sun. It takes the approximately 365 ¼ days to complete one revolution. We consider only 365 days for one year and the remaining 1/4 day is added as one whole day to every fourth year.
• When this is added, that year has one extra day which is called the Leap year. During the Leap year the Extra day is added to the month of February which will have 29 days.
• Physiography of Earth: A continuous stretch of Mountain range in the world is Himalayas. The land that is higher than the surrounding region with a flatted top is called A relatively flat and low lying surface with almost no difference between its highest and lowest points is called plain. There are seven continents like Asia, Europe, North America, South America, Africa, Australia and Antarctica. Large Land masses are called Continent.

6. The Seven Continents:
7. Asia: It is the largest continent. It is situated in the Northern Hemisphere .Our Country India is situated in Asia. The cold desert and the Himalayan Mountain are located in this Continent.
8. Africa: It is the second largest continent in the world .The continent is situated in both the Northern and southern hemisphere. The Equator divides the continent into two equal halves. Nile River: (6695): The longest river in the world and the SAHARA, thelargest desert in the world is found in this continent. This continent is rich in Mineral resources, and has dense forest.
9. North America: The Rocky Mountain situated along the west coast is a very long chain of
10. South America: This continent lies almost entirely in the Southern Hemisphere .The Andes, the world’s longest mountain range and river Amazon (6586 km) the world’s largest river is situated in this continent.
11. Europe: This continent lies almost in Asia. The Alps mountain range is situated in this continent.
12. Australia: Australia is referred to as “island” because it is surrounded by ocean on all four sides. The Great Barrier Reef, world’s largest reef coast of Australia.
13. Antarctica: This continent lies in the South Pole and is entirely covered with snow. Penguins, seals and other living creatures live here.

Island: A piece of land surrounded by water on all sides is called Island; group of Island is called Archipelago.

Oceans: 71% (two third) of earth is covered by water. A large stretch of the water covering a huge area is called an ocean.

There are five oceans on the Earth

1. Pacific ocean
2. Atlantic ocean
3. Indian ocean
4. Arctic ocean
5. Antarctic ocean

The sea to the east of Tamil Nadu is called the Bay of Bengal and the sea to the west of Kerala is called Arabian Sea.

1. Pacific ocean: It is the deepest ocean in the world. The volcanic mountains surrounding the Pacific Ocean is called the Pacific Ring of fire. The Mariana Trench is located in this ocean.

2.Atlantic ocean: It is the second largest Ocean in the world. Hurricanes are very common in this ocean.

3.Indian ocean: It is the third largest ocean in the world. India receives Rain fall from the monsoon which originates in this ocean.

4. Antarctic Ocean: This Ocean surrounding the continent of Antarctica is called the Southern Ocean.
5. Arctic ocean: This is the smallest ocean in the World. It is surrounded by the North pole. The ocean is full of icebergs.

Elements of the Earth:

• The peaks of the Himalayan Arctic Circle and Antarctic Circle are covered by snow and not with water. The atmosphere is filled with water vapour, cloud and moisture. The Water on the earth is found in three forms namely solid, liquid and gas. Apart from that air is present. Though we are always surrounded by air we feel its presence only when the wind and cyclone is present.
• The zone in which living organization exist is called Biosphere.
• The combination of the Lithosphere, hydrosphere, and atmosphere is called Biosphere. Hence if any one of these is polluted, the living organisms are affected. Many species of plant and animals are present on land

Maps: A map is a representation of the Earth or part of it and is drawn to scale on paper or on cloth.

• A map without a scale is called a sketch map. A blue print is commonly called as a plan. Conventional signs and symbols help us to understand direction different features on map. The direction is indicated on top right hand corner of every map.
• Scale: Scale is indicated at the bottom of the map. Scale is the distance between the two point places on the map to the corresponding distance on the ground.

Classification of maps: Physical features like mountains, plateaus, rivers and oceans are on a Physical map. Countries states, districts, cities, villages and other’ boundaries are drawn on a Political map. Maps that show temperature, forest, and minerals resources are drawn based on a theme, hence they are called Thematic map. E.g. The Transport map of India and the Industrial map of Tamil Nadu which are given.

Use of Maps:

• It is used to locate places
• It is used to locate resources that are found in the earth
• It helps the military to move its troops.
• It helps in planning
• It helps us to know the movement of the satellite and planets in the sky
• Globe: A Globe is small true model of the earth. Globe is also made to an inclined axis like the rotating earth which is inclined at an angle of 23 1 /2 ⁰ on its axis

Latitudes and Longitudes:

• We draw few imaginary lines on the earth’s surface, when we want to locate a place; we try to find out between which two lines this place is found.

• The Earth is a sphere and it consists of 360⁰. The equator is the 0⁰ This is important latitude. Similarly it is indicated as 10 W and 10⁰E. Greenwich meridian is considered as central longitude. ‘W’ stands for places west of the Greenwich meridian and ‘E’ the places east Greenwich meridian.

Our Home Planet Earth:

6. Structure and Tectonic Movements:

• The Earth our home land, mother planet, is the important member in the solar system. The Egyptians visualized that earth was a floating sphere on the sea.
• Formation of Continents and Oceans: A few million years ago, all the present continents were clustered together around the South Pole. This Super continent was called Pangea. In Greek, it means “all earth”. The ocean called the Panthalassa or the Super Ocean. In Greek, it means “all water”. The Pangea was broken into a number of plates known as the lithosphere Plates.
• The Pacific plate is the largest plate and it covers about 1/5^th of entire Earth’s surface. The Himalayas is rising by about 5mm per year, to the movement of Indo-Australian plate, and the plate is still moving at 67 mm per year. The scientists expect that, in another 10 million years, the plate will travel about 1,500 km into Asia.

7. Earth’s Interior :

• Three main layers or shells exist within the Earth. The part of the earth we live is a very thin layer is relative to the inner earth.

They are the crust, mantle and the core.

Crust:

• The upper layer of the earth’s surface is called the “crust or lithosphere”. The continental crust is composed of a layer called the”SlAL” which is made up of Silica and Aluminium. The oceanic crust is composed of basaltic layer called the ‘SIMA” which is made up of Silica and Magnesium. Crust is thicker on the continents and thinner on the ocean floors .The SIAL layer is floating on the SIMA layer. The average depth of SIAL is about 20 km and the average depth of about 25 km. They average density of the crust is about 3 km.

Mantle:

• It is made up of plates that move and create continental drift. Beyond 900km this layer is completely homogeneous. Upper mantle is known as “asthenosphere” It extends up to depth of 700km.Lower mantle is semisolid and is plastic in nature. The average density of the mantle is about 8.

Core:

• The inner most layer of the earth is called “core of barysphere”. It is otherwise known as NIFE, because of the presence of Nickel and ferrous (iron).This layer produces earth’s magnetic field. The density of the core is about 12.The experience of volcanic eruption, hot springs and mines heat increases as we move downwards into the earth.
• The temperature is estimated at the centre of the Earth to be, as high as 5000°C. The normal gain rate of temperature is 1°C for every 32 meters of descent. The Tethys Sea was a shallow sea between the Angara and Gondwanaland. The Great Rift Valley of East Africa and the Narmadha valley in India are the best examples of such basins bounded by faults.

8. Earthquakes :

• An earthquake is a sudden shaking or trembling of a part of the earth’s crust which results in tremors or vibrations. They are classified as volcanic earth tectonic earthquakes. The volcanic earthquakes occur along with eruption and the tectonic earthquakes are caused by their deformation or displacement in the rocks. There are annually 8000-10,000 earthquakes occurring in the world. The Richter scale is used to measure the intensity of an earthquake

Types of Earthquake Waves:

• Basically it is divided into body waves and surface waves. Body waves are produced by the release of energy at the focus and move in all directions through the body of the earth. There are two types of body waves:
• Primary waves
• Secondary waves
• Primary waves or P-waves move faster and are the first to be recorded by the seismograph. It is similar to the sound waves and travel through gaseous, solid materials.
• Secondary waves or S-waves are slower than the P-waves. It can travel through solid materials. During the occurrence of secondary waves, particles move in the direction of wave travel. These waves cause most of the damages on the surface. They are also known as L-waves. They travel at a speed of 4km / sec.

9. Volcanoes:

• A volcano is a vent or an opening on the earth’s crust, through molten materials erupt from the interior.

When the magma erupts out of the earth on to the surface, it is called Lava

• The materials erupt from the interior of the earth’s crust with huge explosions or quiet in nature.

Types of Volcanoes:

Volcanoes can be classified into three types based on the eruption.

• Active
• Dormant
• Extinct

Active volcano: It erupts lava frequently. Most of the active volcanoes are formed along the mid-oceanic ridges.

Northwestern part of the Deccan plateau of India has been made up of volcanic lava.

Dormant Volcanoes: They are also called sleeping volcanoes. These volcanoes have been active in the past, stopped ejecting lava now, but it can erupt at any time in the future.  The Vesuvius of Italy and Mauna kea in Hawaii are the best examples.

Extinct Volcanoes: Extinct volcanoes are also called as dead volcanoes. They erupted in the past but they did not do so recently and in future it is expected there will not be any eruptions.  Mt. Kilimanjaro in Africa and Narcondam Island near the north-east of North Andaman Island of Indian territory are some examples of extinct volcanoes. The famous Tiruvannamalai hills of Tamil Nadu and Panaka hills of Andhra Pradesh are also considered as extinct volcanoes.

Dynamic Earth Surface:

10. Weathering :

Weathering is the process of disintegration or decomposition of rocks

 Weathering can be classified into

• Physical (or mechanical)
• Biological weathering.
• The Government of India banned the tanneries around Tajmahal due to acid rain caused by these industries which affects the marble wonder of the World.

Weather and Climate:

Weather:

• Weather refers to the physical state of the atmosphere within 24 hours described by weather elements such as temperature, atmospheric pressure, humidity, rainfall, cloudiness, wind, speed and Wind direction.

Climate:

• The word climate is commonly defined as the weather average over a long period of time and over a large area. The standard averaging period is 30 years.

Determinants of Climate and Weather:

• Latitude: The equator receives vertical sunrays which fall, over a contrast, the Polar Regions receive slanting sunrays and they fall over a wider area. As a result of this, the places near the equator are hotter than the poles. For example, Madurai in Tamil Nadu is hotter and Moscow, Russia is colder.
• Altitude: The weather and climate are modified by the mountains and hills. The places located on higher altitudes are ‘always cooler than those on the plains. This is because the air becomes thinner and they absorb only less heat. For example Ooty and Kodaikanal are cooler than Thiruchurapalli. Temperature decreases at the rate of 6.5⁰C for every 1000 metres high on the Earth’s surface.
• Distance from the Sea: The empty vessel is compared with the sea. The sea absorbs and retains heat for long duration like the vessel with water. The coastal areas experience the cool, wet air from the sea throughout the year which modified weather along the coast to have uniform weather both in the winter and summer.
• Ocean Currents: Based on temperature the ocean currents are classified as Warm Ocean Currents and Cold Ocean Currents. Warm currents make coastal areas warm, wet and free from ice and cold currents make them cool, dry and to have icebergs. The meeting places of warm and cold ocean currents are the areas of major fishing grounds because the conditions are suitable for the growth of the fish food, plankton. At that same time, these areas are dangerous for shipping as they are suitable for the formation of dense fog and low clouds.

El Nino Effect:

• El Nino means “The Christ Child” in Spanish. It is formed around Christmas time and continues for a few months. During this period, once in five or six years the temperature rises rapidly and low pressure system is formed along the coast of Peru and Equator. It attracts winds from all directions. So the trade becomes very weak over the Pacific Ocean and Indian Ocean and these winds are deflected causing a prolonged dry period in India.
• Human influence: Industrial revolution brought changes in our lifestyle. Terrestrial radiation is referred to as heat energy emitted from the Earth.

11. Earth’s atmosphere :

• The atmosphere of the Earth is surrounded by gases which are retained by Earth’s gravity. Earth’s atmosphere is made up of a combination of gases. The Argon, Neon, Ozone, Helium, Krypton, Carbon di oxide and so on are the other gases found in little quantities. Based on the characteristics of the atmosphere, it is divided into four major layers, as troposphere, stratosphere, ionosphere and exosphere.

Troposphere:

• Troposphere begins at the surface of the ‘earth and extends up to 8 km at the poles and 18 km at the equator. This layer is known for all kinds of weather changes such as temperature, pressure, winds, clouds formation and rainfall. In this layer alone, the temperature decreases with increasing altitude. The tropopause is a thin layer lies between the troposphere and the stratosphere.
• Meteorology is the scientific study of the atmosphere focusing on weather processes and short term and it is study of lower layer of the atmosphere.

Stratosphere:

• Stratosphere extends for about 80 km. Temperature increases with height. This is the layer where most jet planes fly. The top edge of the stratosphere is rich in ozone. Ozone is very important to all living things on earth. It captures the ultraviolet rays of the sun and takes the harmful effects out.

Ionosphere:

• Ionosphere stretches from 80 km to 500 km. It is called ionosphere because, in this part of the atmosphere, the sun’s radiation is ionized. It reflects the radio waves back to the earth’s surface which are useful for modem communications. This zone is also called isothermal layer and ozonosphere.

Aerology is a branch of meteorology involves observation and research of the atmosphere using air balloons, radio transponders and airplanes.

Exosphere:

• The exosphere is the uppermost layer of the atmosphere. The main gases within the Earth’s exosphere are the highest gases, mainly hydrogen and helium. The instrument used to measure the temperature is called thermometer. The imaginary lines join different places with same temperature on the map is called Isotherms.

Measurement of Temperature:

• There are three scales to measure temperature. They are:

1. Celsius
2. Fahrenheit and
3. Kelvin

Air Pressure

• Air pressure is defined as the pressure thrust by the weight of the air on the earth’s surface. The average air pressure at the sea level is 1,013 millibars. The horizontal distribution of the air pressure is highly influenced by the temperature of a given place. Barometer is the instrument used to measure the atmospheric pressure.

12. Pressure Belts of Earth:

• Equatorial Low Pressure Belt: This belt lies between 5°N and 5°S.The sunrays are vertical over here throughout the year. Since temperature is high the air becomes lighter and ascending. It causes low pressure conditions. This Zone is otherwise called as “a belt of Calm” or”Doldrums”.
• Sub-tropical High Pressure Belt: This zone lies between 25⁰ and 35⁰ latitudes in both the hemispheres. The ascended air from the tropics is getting cooled due to low temperature at about 30° – 35° latitudes. In ancient times, the merchants carrying horses in their ships had to throw some of them out while passing through this zone of the calm in order throw lighten the ship. Hence, this zone is called “horse latitudes”.
• The imaginary lines joining different places with the same pressure on map are known as isobars.
• Sub-polar Low Pressure Belt: This belt lies between 60° – 65° latitudes in both the hemispheres and the air spreads outward from this zone due to the rotation of the earth so the low pressure is produced.

Polar High Pressure Belt:

• This pressure belt persists at the poles. The sunrays fall at the poles and as a result the temperature is low and heavy air produces high pressure.

 Anemometer is an instrument used to measure the velocity of wind.

Wind vane is used to indicate the direction of the wind.

• All moving objects including-winds and ocean currents tend to get deflected towards right in the Northern hemisphere and left in the southern hemisphere due to the rotation of the earthThis changing principle is called the Ferral’s law or coriollis force

Winds Classification:  The winds are classified on the basis of the duration of winds and place of Origin Planetary winds: The winds that blow from a particular direction throughout the year is known as the planetary winds.

• The major trade winds are given below: The trade winds blow within the tropics, as southeast trades and Northeast trades. They are called so because once it was favorable for sailors. They are regular and constant especially over the sea. These winds are getting deflected due to Ferral’s law.
• The Westerlies blow from the subtropical high pressure to the Sub polar low pressure belt in both the hemispheres. In the northern hemisphere, they blow as south westerlies and in the south it blows as the north westerlies. These winds blow along the Earth’s rotation from west to east.
• The Polar winds blow as easterlies from polar high pressure to the sub-polar low pressure. They are bitterly cold winds and they penetrate into many parts of the interior areas. Example, USA but in India they are blocked by the Himalayas.

Seasonal and periodic winds:

• These winds are mainly caused due to the differences in heating and cooling of the surface of the earth. These winds blow only at specific time.

Monsoon wind :

• The monsoon is derived from the word”Mausim”, which means Seasons. The monsoon wind is further divided into Southwest Monsoon and Northeast Monsoon. The Southwest Monsoon winds blow from the south Indian Ocean and South Pacific Ocean towards Asia whereas the Northeast Monsoon winds blow from the Asian high pressure areas to the Indian Ocean and Pacific Ocean.

Sea breeze:

• During the day lime, the land becomes warmer than the adjoining water bodies. As a result, a low pressure on the land and a high pressure on thewater body is formed; this leads to the cool wet breeze from the sea blow towards land in the late evening.

Land Breeze:

• During the night time the land becomes cooler than the adjoining water bodies. So that there is a high pressure on the land and the low pressure on the water body is formed followed by that the cool dry breeze from the land blow towards the sea in the early morning

Variable winds:

• The variable winds have no definite location or direction. These winds are getting fluctuated by means of its direction and speed.

13. Cyclones :

• The cyclones are the centers of a low pressure system. They attract winds from all direction. Moreover, they are associated with heavy rain and high speed winds. The centre of the cyclone is vacuum area which is termed as “the eye of the cyclone”
• According to its origin and its location it is called by different names such as cyclones, typhoons and hurricanes. They move in anti-clockwise in northern hemisphere and clock wise in the southern hemisphere.

Anticyclones:

• The anticyclones are the centers of the high pressure systems from which the wind movement takes place outward. These winds are associated with clear weather and no rainfall. The anti-cyclones move clock wise in the northern hemisphere and anticlockwise in the southern hemisphere.

14. Clouds :

• A cloud can be defined as a mass of small water droplets or ice crystals formed by the condensation water vapour in the atmosphere.  Clouds are formed by very minute suspended water particles present in the atmosphere.
• According to the shape and altitude, the clouds are classified as Cirrus, Stratus, Cumulus and nimbus.
• Cirrus clouds high clouds because they are formed above 5,000 meter above sea level. Stratus clouds are low clouds because they are formed within 2,000 meter above the sea level. They have uniform base and look like a dark gray sheet. They may cause snow and drizzle.
• Cumulus clouds are often described as “puffy” or “cotton-like” in appearance which are medium clouds. Cumulus clouds may appear alone in lines or in clusters. These clouds are associated with rainfalls, lightning and thunder. They are otherwise called as thunder clouds. They extend up to 12,000 metres high above the sea level.
• Nimbus clouds are vertical clouds. They are thick dark or gray or black clouds. They cause continuous rainfall so they are known as storm or rain clouds.

15. Rainfall :

• Rainfall may be defined as the water drops that fall from the clouds to the earth.
• The mechanism of rainfall begins from evaporation and then it continues condensation at considerable heights.
• Later on, the clouds are formed which may cause rainfall.
• The rainfall types are classified into three as: Conventional,  relief or Orographical,    
• Hygrometer is an instrument used to measure rainfall. The imaginary lines joining different places having same amount of rainfall on a map are known as isohyets.

Convectional rainfall:

• Since the equatorial regions receive vertical sunrays they become hot, so that the hot air expands and rises vertically upwards. As the temperature reduces gradually, the air gets cooled and forms clouds. When the clouds reach the dew point, they cause rainfall. This is known as the convectional rainfall. This type of rainfall is accompanied with thunder and lightning. Usually, it occurs around 4‘O clock; hence, it is called 4’O clock rainfall.

Cyclonic rainfall:

• Due to Earth’s rotation, the wind gets deflected and a circular motion of wind develops. The air rises upward in the form of a funnel. The rising air gets cooled and condensation takes place. This brings heavy rainfall in the low pressure centers. Example during October, November and December, the Northeast Monsoon season period, there are a number of cyclones caused along the coast of Tamil Nadu, Andhra Pradesh and Orissa.

Lightning:

• Lightning can be defined as the atmospheric discharge of electricity. It is accompanied by thunder. It travels at a speed of 96,560 miles. The study or the science of lightning is called Fulminology. The person who studies lightning is referred to as Fulminologist.

Thunder storm:

• Thunderstorms are produced by cumulonimbus clouds. They are usually of short duration. They are accompanied by lightning, thunder, strong wind gusts, heavy rain and sometimes hail. Since the thunderstorms are accompanied by many weather elements Meteorologists referred to these as weather factories. The formation of the thunderstorms ranges from 4 to 20 km.

16. Disaster and Disaster Management:

• The definition of the United Nations is: “A serious disruption of the functioning of society, causing widespread human, material or environmental losses which exceed the ability of affected society to cope using only its own resources.

Mitigation:

• It means to make less severe. Therefore, it can be defined as taking action to reduce the effects of a hazard.

Earthquake:

• As we know, the trembling of the earth is known as earthquake. Earthquakes may cause multiple fires, trigger floods through failure of dams and landslides. The vibration causes damage and collapses structures. Tidal waves and tsunamis are also caused. It may cause breakdown in sanitary conditions, water supply, electricity, failure of all transport system. Apart from all these earthquake results in loss of life.
• It is divided into four seismic zones. They are listed in the following table:

Mitigation Plan during Earthquake:

• The most important thing to do during an earthquake is to be calm. If you are inside a building, stand at the door way or crouch under a desk or table, away from windows or glass fixtures. If you are outdoor, stay away from objects such as electrical poles, buildings, trees, telephone and electric wires. If you are in automobile drive away from under passes or over passes and stop at a safest place possible. Encouraging the people to build earthquake prone houses.
• People living in the multistoried building should never use the lift to come out of the building instead they should use the staircase. Switch off the cooking gas stove, electrical lights, candles, and other lamps to avoid fire accidents. Check the soil type before construction and do not build structures on low quality, soft solid.

Volcanic Eruptions:

• Unlike earthquakes, volcanic eruptions can be predicted well in advance because, earlier to eruptions, smoke, outflow of gas and slight tremors are caused. Due to volcanic eruptions, the forests are cleared; snow melts and leads to floods, affect human settlements. Though volcano is a destructive force, it also produces benefits. The volcanic materials are useful for industrial and chemical purposes.

• Rocks formed by lava are used for building roads; weathered volcanic ash greatly improves soil fertility. Steam and hot springs from a volcano is used to generate geothermal energy. Likewise, the most recent volcanic eruption occurred on April 14, 2010, which erupted with a large ash – plume( due to magma coming out under ice) More than 20 airports have been shut down in Europe because of the event .

Mitigation plan:

• Volcanoes rarely kill people should stay away from volcanoes. All transport facilities should be avoided especially air transport near volcanic regions. Volcanic eruptions may cause earthquakes. So people should take precautionary measures. From the snow covered mountains, the volcanic eruptions may cause melting and flooding and therefore embankments must be build. People should be aware of the results of tilt meter which measures the expansion of a volcano.

Tsunamis:

• They are killer waves or Giant waves generated by earthquakes, volcanic eruptions or underwater landslides. It can reach 15 meters or more in height. When earthquakes occur in the sea or ocean, the sea waves rise to several meters and may reach the coast within a few minutes. The danger period of Tsunami can continue for many hours, after a major earthquake. The term “Tsunami” has been coined from the Japanese word.

• “Tsu” means harbor and “nami” means waves. Tsunami waves travel at a speed of 320 kilometer per hour and speed increases when it approaches the continents. A killer Tsunami hit South East Asia countries on the 26^th of December of 2004, killing more than 1,50,000 lives.   In India Tsunami warning centers has been set up at Hyderabad

Mitigation plan:

• People should be aware of the information given by the Tsunami Warning Centre located at Hyderabad in India. People should vacate the coastal area as soon as the tsunami warning is released. Seriously injure persons should be given immediately First Aid. Fisherman should not go for fishing. We should not assume that the first wave is dangerous whereas the successive waves would be more dangerous.

Landslide:

• Landslide may be defined as the mass of rocks and debris move down a slope. Debris flow is also known as mudslide. Landslides are caused due to instability of the slope, heavy rainfall, earthquake, volcanic eruption, deforestation and also indiscriminate construction activity. Landslides affect agricultural production, destroy settlements, damage roads and railways and change the direction of surface run off.

Mitigation Plan:

• If houses are built on soft solids and slide prone areas, should be prepare alternative path for sliding soil to deviate. The warning signals of landslides are; the doors and windows become tightened. When chances are there for the closure of road mudslide, two or three Alternative planned routes may be planned for escaping quickly.

• If at home when a landslide occurs do not come out of the house. When there is no escape any you are trapped in a landslide, kneel or sit close to the floor and place your hands at the back of the neck. Look out for people trapped and give them first aid for serious injuries and evacuate them to safer places.

Avalanche:

• An avalanche can be defined as a large mass of snow or ice, descending down the mountain slope. It occurs in the high latitudes and at the high altitudes. Avalanches are provoked by earthquakes, extreme precipitation, and manmade disturbances such as loud noise, heavy movement of the skiers and use of explosives. The avalanches become severe when more accumulation of snow takes place at the time of avalanches. The effects of Avalanches are destruction and blockage of the roads, destroying a small hamlet, vegetation and wild life.

Mitigation plan:

• It is difficult to check or stop the avalanches but the power of avalanches can be reduced to minimize its effects. Hill resorts, mountain towns, roads and railways are to be avoided in the areas of avalanches. People should be instructed to not to use explosives. People who live on hill slopes should be encouraged to plant trees around their houses. In areas of avalanches, travelling of transport should be avoided. 

Cyclones:

• South Indian coastal are mostly affected by cyclones than by any other disaster. Every year, cyclone claims a few deaths along the Coromandel Coast, especially in Andhra Pradesh and Orissa. The Indian Coastal regions are among the six major cyclone prone regions of the world. The Cyclones are the strongest winds generated by the meeting for the cold and warm fronts in the centre of low-pressure systems.
• When they are all formed over the sea and oceans they become violent due to the fact that there are no barriers to check these winds. The cyclones are always associated with strong winds, torrential rains, may lead to floods, uprooting of trees, affecting the drainage systems, breaking down of electricity, transport, water logging spreading of diseases, destruction to the crops, soil erosion, collapse of old buildings along with these loss of life.

• On October29, 1999, Super cyclone with winds of 260-300 km/ hour hit the 144 km coast of Orissa with a storm surge. It created the Bay of Bengal water level rise 8 meter higher than normal. The super storm travelled more than 250 km inland and within 36 hrs ravaged more than 20 million hectares of land, devouring trees and vegetation, leaving behind huge trail of destruction.

Mitigation plan:

• People are to be instructed to shift from low lying areas to nearby elevated areas. In the areas of water logging, temporary pits to be built to drain the water. People, who are living in old building, have to change their places, at least temporarily.  People have to safeguard their belongings such as important documents and jewels. 

• We need to have secure drinking water pipelines. People have to watch out while going out to see into whether any breakages, leakages in electricity from the nearby post. Fishermen must be advised not to go for fishing.  All have to listen to the local Radio and TV for instructions. All have to drink boiled water to avoid spread of diseases.

Floods:

• Floods are a temporary inundation of overflow of water. They are caused due to very heavy rainfall, cyclones, melting of snow, tsunami or a dam burst. Floods are the common features in Tamilnadu, Andhra Pradesh, and Orissa due to very heavy rainfall during the Northeast Monsoon season and in Mumbai during the Southwest Monsoon season.

• Floods destroy sewage system; pollute water, cause soil erosion, silt deposition, water logging, and destruction to agricultural fields, livestock, and damage to the fishing equipments, building structures and to the loss of life. Floods and droughts are the two problems caused due to the vagaries of monsoon.

Mitigation plan:

• To avoid overflow of water many measures are required, to drain, especially near the agricultural fields and low lying areas. River embankment, desilting are needed especially in the ponds and lakes. Sand bags are to be kept in front of houses in the low-lying areas to block the water reaching inside. Afforestation must be encouraged and to follow any one of the rain water harvesting methods. People from the low-lying areas are to be shifted to elevated areas. Students are to be trained to take part in the social activities at the time of floods.

Drought:

• Drought refers to the prolonged dryness of weather due to lack of rainfall. It is difficult to indicate the time of its onset and end. According to the Indian Meteorological Department, the country is declared as drought affected when overall rainfall deficiency is more than 10% over a long period. The major reason for the drought is the scarcity of rainfall.
• Scarcity of rain can be listed due to failure of monsoons, vagaries of monsoons, deforestation, environmental degradation, high rate of evaporation, poor land management, over grazing and soil erosion. The Rain fed crops are mostly affected due to droughts. Other effects are:

1. Scarce drinking water supply
2. Shortage of food
3. Lack of water to the livestock
4. Nutrition deficiency diseases and
5. Soil erosion

Mitigation Plan:

• Planned land use development through alternate cropping and drip irrigation. Proper storage and usage of a Arrangement for cattle fodder and drinking water in the drought regions. Drought relief planning is needed at village level. Importing and transporting required food to the needy areas is important.

Tornadoes:

• Tornadoes refer to the violently rotating columns of air. They extend to from a funnel shaped cumulonimbus cloud to the earth. Their width varies from a few meters to more than a kilometer and it rotates at a speed between 64 km and 509 km per hour. They are caused due to extreme low pressure. They originate inland, generating a rapid whirl wind. They are formed when hot air and cold air are mixed.
• They cause heavy destruction to both life and property like a cyclone, On March 24, 1998: Violent tornado or tornadoes killed 160 people and injured 2,000 when they streaked through 20 coastal villages on the eastern states of West Bengal and Orissa. Ten people were killed when the boat they were travelling in about. Thirty-five children were crushed to death when a school building being used as a shelter collapsed at Goborghata in the Balasore district in Orissa. The tornadoes flattened 15,000 homes and left more than 10,000 people homeless.

Mitigation plan:

• As soon as tornadoes are observed, people should be inside their houses (or) storm cellar if not lie in the low- lying area. Help injured or trapped persons and give first aid immediately.

Common Mitigation Strategy:

• First every individual should know how to safeguard themselves from disaster. People should be given the demonstration program on “keeping safe’ at the time of disaster and after disaster. Listen to a battery operated radio for emergency information and relief measures.