Safety and Disasters
(Excursions)
Workout
A. Fill in the blanks with the correct answers.
1. The tremors caused by earthquakes are called .....
a. seismic waves. [✓]
b. volcanic activity. [ ]
c. fault lines. [ ]
d. crests. [ ]
2. Japan, Chile and Italy belong to ............ earthquake zone.
a. zone two. [ ]
b. zone one. [ ]
c. zone three. [✓]
d. zone four. [ ]
3. ................. occur within 2 to 6 hours and sometimes within seconds.
a. Droughts. [ ]
b. Flashfloods. [✓]
c. Earthquakes. [ ]
d. Fires. [ ]
4. Electrical hazards cause ....................
a. floods. [ ]
b. fires. [✓]
c. earthquakes. [ ]
d. tsunami. [ ]
5. Earthquakes occur along the ............. of the Earth's crust.
a. oceanic plates. [ ]
b. fault lines. [✓]
c. seismic lines. [ ]
d. earthquake lines. [ ]
B. Answer these questions in brief.
1. Name the major earthquake zones of the Earth.
= The largest number of earthquakes occur in the following zones of the Earth:
❐ Zone One : It extends around the Pacific Ocean, which includes the western coasts of the Americas, Central America and the West Indies.
❐ Zone Two : It is located in the Indonesian archipelago and the Himalayan region. It stretches further to the Hindu Kush Range, some regions of the Caucasus and the Atlas Mountains.
❐ Zone Three : It comprises Japan, Chile, Italy, the Philippines and California.
2. What are seismic waves?
= The shaking caused by earthquakes is called seismic waves.
3. Name two types of mitigation strategies for earthquakes.
= Two types of mitigation strategies for earthquake are -
i) Study the seismic map and find out which seismic zone your area is located in.
ii) Make an evacuation plan as suggested by the disaster management team of your locality.
4. Describe the types of floods.
= Floods are natural disasters. They occur when incessant and heavy rainfall causes water bodies to swell. Excess water overflows and fills in the nearby areas. Buildings, farms and roads are submerged causing destruction.
Floods can also occur due to cloudbursts. Such floods are called flash floods. Flash floods occur within 2 to 6 hours and sometimes within a few seconds. Slow floods occur slowly and can last for days and weeks.
5. What is an industrial fire?
= Industrial fires and explosions cause loss of life and damage to property. Industrial fires mainly occur because of the following reasons.
❐ Combustible dust is a major cause of fire in food processing industries, chemical industries and manufacturing industries.
❐ Fire is also caused by the sparks generated from heavy machinery.
❐ Flammable substances used in the chemical industry lead to fires.
❐ Faulty wiring used in the industries cause fire.
C. Answer these questions in detail.
1. What are the effects of an earthquake?
= Earthquakes cause changes to the Earth's surface. People can neither predict an earthquake nor prevent it. However, seismologists can map earthquake-prone regions of the world. In these regions, special mitigation methods are adopted to reduce the impact of an earthquake.
Some impacts of an earthquake are given below:
❐ Landslides.
❐ Large-scale destruction as buildings collapse.
❐ Serious fires.
❐ Roads and railways cave in.
❐ tsunamis if the earthquake originates below the sea on the sea floor, causing unprecedented damage to life and infrastructure.
2. Write five safety measures one should take during an earthquake.
= Five safety measures one should take during an earthquake are -
❐ Stay calm.
❐ Stand against a wall near the centre of the building.
❐ Stand in the doorway.
❐ Stay away from windows.
❐ Stay away from glass furniture and wall hangings.
3. What are the major causes of flood?
= Some of the causes of floods are :
❐ Heavy rains are the most common causes of floods. Floods are common during the monsoon. Heavy rainfall fills lakes and rivers beyond their holding capacity. As a result, they breach their banks, and water inundates the adjoining areas. For example, Mumbai and Chennai often face the threat of floods during monsoon.
❐ The coastal regions experience frequent and powerful cyclones. The sea water carried by powerful winds enters coastal regions and floods them.
❐ Dams are build on rivers to harness river water for generating hydroelectricity and for irrigation. Sometimes, when the volume of water in the dam increases beyond capacity, the dam can break and submerge surrounding areas. Thus, excess water is released from the dam to prevent it from breaking, which results in flooding of the catchment area.
4. Explain the safety measures one should take during floods.
= The safety measures one should take during floods are -
❐ As soon as flood warning is signals, we should try to move to a safer area.
❐ Turn off all the electrical appliances, gas stoves and heating appliances before evacuating.
❐ Leave the flooded area as soon as possible. Carry a walking stick as the water will have a high undercurrent.
❐ Stay away from power lines or broken power transmission cables to avoid accidents.
❐ Try to keep away from flood water as it may contain other hazardous materials.
❐ Keep yourself updated about the weather report.
❐ Put chlorine tablets to purify the drinking water as waterborne diseases are very common during floods.
5. What are the major causes of fires?
= Industrial fires and explosions cause loss of life and damage to property. Industrial fires mainly occur because of the following reasons.
❐ Combustible dust is a major cause of fire in food processing industries, chemical industries and manufacturing industries.
❐ Fire is also caused by the sparks generated from heavy machinery.
❐ Flammable substances used in the chemical industry lead to fires.
❐ Faulty wiring used in the industries cause fire.