I. Choose the correct answer
1. The major reason for the drought is the_______________ .
(a) Scarcity of rainfall (b) environmental degradation (c) A forestation (d) Industry
2. Tornadoes are common in
(a) India (b) Bangladesh (c) China (d) U.S.A
3. Landslides often occur in
(a) Desert region (b) Forest region (c) Tundra region (d) Hilly region
4. The word Tsunami has been derived from
(a) Tamil (b) French (c) Japanese (d) Latin
5. Of the following which is not a natural disaster
(a) Nuclear explosion (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.
It means “to make less severe”. Therefore, it can be defined as “taking action to reduce the effects of a hazard”.
2. What is Landslide?
Landslide may be defined as the mass of rocks and debris move down a slope.
Debris flow is also known as mudslide.
3. Differentiate floods and droughts.
· 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.
4. Differentiate Tornadoes and Cyclones.
· The cyclones are the strongest winds generated by the meeting of 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.
· Tornadoes refer to the violently rotating columns of air.
· They extend from a funnel shaped cumulonimbus doud to the earth.
· Their width varies from a few meter to more than a 36 kilometer and it rotates at a speed 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 are broadly classified into Natural and Man- made. The natural disasters occur due to the natural forces whereas the man-made disasters occur due to human negligence, carelessness and ignorance.
2. Write about Tsunami and its effects on environment.
v They are killer waves or Giant waves generated by earthquakes, volcanic eruptions or underwater landslides.
v It can raise to 15 metres 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.
v The danger period of Tsunami can continue for many hours after a major earthquake.
v 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 Asian Countries on the 26th December of 2004 killing more than 150000 lives.
v The emotional, economic and ecological toll of the disaster cannot be calculated. Many villages have lost entire generation.
v This was the biggest earthquake to hit the world in 40 years.
v No one could have thought that its effects would ripple worldwide overnight.
2. What are floods? List out the Mitigation measures of flood affected areas.
v 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.
v Floods are 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.
v Floods destroy sewage system, pollute water, cause soil erosion, silt deposition, waterlogging, destruction to agricultural fields, livestock, damage to the fishing equipments, building structures and to the loss of life.
v Floods and droughts are the two problems caused due to the vagaries of monsoon.
v To avoid overflow of water, many channels are required, to drain, especially near the agricultural fields and low-lying areas.
v River embankment, desilting are needed especially in the ponds and lakes.
v Sand bags are to be kept in front of houses in the low-lying to block the water reaching inside.
v Afforestation is to b e encouraged to follow any one of the rain water harvesting methods.
v People from the low-lying areas are to be shifted to elevated areas.
v Students are to be trained to take part in the social activities at the time of floods.
3. What is called drought? Write about its effects.
v Drought refers to the prolonged dryness of weather due to lack of rainfall.
v 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.
v The major reason for the drought is the scarcity of rainfall.
v Scarcity of rain can be listed due to failure of monsoons, vagaries of monsoons, deforestation, environmental degradation, high rate of evaporation, poor land management, overgrazing and soil erosion.
v The rainfed crops are mostly affected due to droughts.
v Other effects are:
(i) scarce drinking water supply,
(ii) shortage of food,
(iii) lack of water to the livestock,
(iv) nutrition deficiency diseases and
(v) soil erosion.
4. Write about the seismic zones of India.
India is divided into 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 set up at HYDERABAD.
4. Debris flow is also known as MUDSLIDES
5. Avalanches occur on the high and high LATITUDE AND ALTITUDE