I.Choose the correct answer
1. The major reasonfor the drought is the_______________ .
(a)Scarcity of rainfall (b) environmental degradation (c) Aforestation (d) Industry
2. Tornadoes arecommon in
(a) India (b)Bangladesh (c) China (d) U.S.A
3. Landslides oftenoccur in
(a) Desert region (b) Forest region (c) Tundraregion (d) Hilly region
4. The word Tsunamihas been derived from
(a) Tamil (b)French (c) Japanese (d) Latin
5.Of the following which is not a natural disaster
(a) Nuclearexplosion (b) Deforestation (c) Forest fire (d) Lightning
II.Match the following
1. Tornadoes – Rotating air 1
2. Molten rocks – Volcanic eruption 2
3. Landslide – Heavy rainfall 3
4. Drought – Scarcity of rainfall 4
5. Earthquake – Tsunami 5
III.Answer the following questions briefly
1.Define Mitigation.
Mitigation
It means “to makeless severe”. Therefore, it can be defined as “taking action to reduce theeffects of a hazard”.
2.What is Landslide?
Landslide
Landslide may bedefined as the mass of rocks and debris move down a slope.
Debris flow is alsoknown as mudslide.
3.Differentiate floods and droughts.
Drought
· Droughtrefers to the prolonged dryness of weather due to lack of rainfall.
· Itis difficult to indicate the time of its onset and end.
4.Differentiate Tornadoes and Cyclones.
Cyclones
· Thecyclones are the strongest winds generated by the meeting of the cold and warmfronts in the centre of low-pressure systems.
· Whenthey are all formed over the sea and oceans they become violent due to the factthat there are no barriers to check these winds.
Tornadoes
· Tornadoesrefer to the violently rotating columns of air.
· Theyextend from a funnel shaped cumulonimbus doud to the earth.
· Theirwidth varies from a few meter to more than a 36 kilometer and it rotates at aspeed between 64 km and 509 km per hour.
IV.Answer the following questions in detail
1.What do you meant by disaster? Explain the natural and man made disaster.
The disasters arebroadly classified into Natural and Man- made. The natural disasters occur dueto the natural forces whereas the man-made disasters occur due to humannegligence, carelessness and ignorance.
2. Write about Tsunami and its effects onenvironment.
Tsunamis
v Theyare killer waves or Giant waves generated by earthquakes, volcanic eruptions orunderwater landslides.
v Itcan raise to 15 metres or more in height. When earthquakes occur in the sea orocean, the sea waves rise to several meters and may reach the coast within afew minutes.
v Thedanger period of Tsunami can continue for many hours after a major earthquake.
v Tsunamiwaves travel at a speed of 320 kilometer per hour and speed Increases when it approachesthe continents.
A killer Tsunamihit South East Asian Countries on the 26th December of 2004 killingmore than 150000 lives.
v Theemotional, economic and ecological toll of the disaster cannot be calculated.Many villages have lost entire generation.
v Thiswas the biggest earthquake to hit the world in 40 years.
v Noone could have thought that its effects would ripple worldwide overnight.
2. What are floods? List out the Mitigationmeasures of flood affected areas.
Floods
v Floodsare a temporary inundation of overflow of water. They are caused due to veryheavy rainfall, cyclones, melting of snow, tsunami or a dam burst.
v Floodsare common features in Tamilnadu, Andhra Pradesh, and Orissa due to very heavyrainfall during the Northeast Monsoon season and in Mumbai during the SouthwestMonsoon season.
v Floodsdestroy sewage system, pollute water, cause soil erosion, silt deposition,waterlogging, destruction to agricultural fields, livestock, damage to thefishing equipments, building structures and to the loss of life.
v Floodsand droughts are the two problems caused due to the vagaries of monsoon.
Mitigation
v Toavoid overflow of water, many channels are required, to drain, especially nearthe agricultural fields and low-lying areas.
v Riverembankment, desilting are needed especially in the ponds and lakes.
v Sandbags are to be kept in front of houses in the low-lying to block the waterreaching inside.
v Afforestationis to b e encouraged to follow any one of the rain water harvesting methods.
v Peoplefrom the low-lying areas are to be shifted to elevated areas.
v Studentsare to be trained to take part in the social activities at the time of floods.
3. What is called drought? Write about itseffects.
Drought
v Droughtrefers to the prolonged dryness of weather due to lack of rainfall.
v Itis difficult to indicate the time of its onset and end. According to the IndianMeteorological Department, the country is declared as drought-affected whenoverall rainfall deficiency is more than 10 % over a long period.
v Themajor reason for the drought is the scarcity of rainfall.
v Scarcityof rain can be listed due to failure of monsoons, vagaries of monsoons,deforestation, environmental degradation, high rate of evaporation, poor landmanagement, overgrazing and soil erosion.
v Therainfed crops are mostly affected due to droughts.
v Othereffects are:
(i) scarce drinkingwater supply,
(ii) shortage offood,
(iii) lack of waterto the livestock,
(iv) nutritiondeficiency diseases and
(v) soil erosion.
4. Write about the seismic zones of India.
India is dividedinto four seismic zones. They are listed in the following table:
V)Fill in the blanks
1. A hazard is an EVENT .
2. India is divided in to FOUR seismiczones.
3. In India Tsunami warning centre has been setup at HYDERABAD.
4. Debris flow is also known as MUDSLIDES
5. Avalanches occur on the high and high LATITUDE AND ALTITUDE