Environmental science& Engg: Hazard Any phenomenon that has the potential to cause disruption or damage to people and their environment. For example, an earthquake can cause a tsunami.  Disaster Natural disasters are slightly different. They are the effects of natural hazards on humanity. For example, the tsunami in Indonesia caused a great amount of loss of property and more importantly lives.

1. 1

2. Hazard
 Any phenomenon that has the potential to cause disruption or
damage to people and their environment.
 For example, an earthquake can cause a tsunami.
Disaster
 Natural disasters are slightly different. They are the effects of
natural hazards on humanity.
 For example, the tsunami in Indonesia caused a great amount
of loss of property and more importantly lives.

3. Natural disaster Man-made disaster
 Floods Accidents
 Cyclones Pollution
 Landslides Fire
 Earth-quakes
 Tsunami
 Avalanches
 Volcanic eruptions

4. A flood is an overflow of water that submerges land.
Causes
 Snow melt,
 Heavy rain,
 The failure of a dam,
 An earthquake induced tsunami,
 Accumulation of sediments in river or channel,
 Clearing of forest for agriculture.

5. Effects
 People loss their houses and properties.
 Crops and livestock has been damaged
 Causes widespread contamination and posing serious
threat to human health.

6. Flood management
 Restore wetlands
 Build walls
 Divert the excess water
 Build check dams on small
streams
 River networking
 Flood plains can be used for recreational areas, parks
and wildlife habitats.
 Afforestation

7.  Cyclones form over warm waters in the tropical regions of the
oceans
 A low air pressure presses against the ocean which needs to be
at least 26.5 degrees Celsius.
 The ocean temperature and air pressure push moisture up and
form clouds. The clouds start to rotate faster and faster
creating a tunnel of clouds.
 Depending on its location and strength, a tropical cyclone is
referred to by names such as hurricane or typhoon.

8. Effects
 Causes damage to human life and their properties
 Slow down the developmental activities of the area.

9.  Weather forecasting
 Radar system
 Effect of cyclone can be reduced by
1. planting more trees
2. construction of dams,
3. windbreaks
4. dykes
5. embankments

10.  The movement of earthy material from higher region to
lower region due to gravitation pull
Causes
 Rain
 Movement of heavy vehicles
 Due to earth quakes, cyclones
 Erosion
 Underground caves and mining

11. Effects
 Blocks the road
 Soil erosion increases
 Damage the houses, crops
and livestock.
Landslide management
• Improve cultivation in the sloppy
region
• Concrete support made at the base of sloppy
region
• Unloading the upper part of the slope
• Develop benches to reduce the steepness of the
• slope

12.  An earthquake is a sudden vibration caused on the
earth surface due to sudden release of tremendous
amount of energy in the rocks under the earth.
Occurrence
 Tectonic plates move along their boundaries.
 Due to friction stress develops on the rocks
Causes
 Volcanic eruptions
 Underground nuclear testing
 Decrease of underground water level

13. Effects
 Landslide may occur
 Destruction of buildings
 Deformation of ground surface
 May cause tsunami
Management
 Wooden houses
 Seismologist analyze and indicate the possibility of
occurrence