UGC NET NTA Exam Preparation| Natural Hazards and Disasters & Their Mitigations|Unit-9|part-9|

 UGC NET NTA Exam Preparation| Natural Hazards and Disasters & Their Mitigations|Unit-9|part-9|


Natural hazard is a natural phenomenon that might have a negative effect on humans or the environment.different types of natural hazards and their mitigation are given below:

1. Earthquake: It is a sudden release of energy accumulated in deformed rocks of earth crust the ground to tremble or shake. it can occur suddenly any time of the year without any warning causing severe loss of life and property. Earthquakes are caused due to disequilibrium in any part of the crust of the earth such as, volcanic eruptions, faulting and folding, hydrostatic pressure of man-made water body etc.

Mitigation of Earthquakes:

  • Follow the certain building codes and guidelines for safe construction of buildings against earthquakes.
  • Educating the public about causes and characteristics of an earthquake.
  • Preparedness measures helps to a certain extent in mitigating the natural disaster.

2. Tsunamis: when an earthquake originates on the sea floor it causes waves of very high magnitude that lead to ocean water surge inland as very high waves for several kilometers sometimes.

Tsunamis destroy everything in their way and cause huge damages to all kinds of structures and causes deaths in large numbers.

pacific coastal area that are more prone to volcanic activity and earthquakes are more prone to hazard of tsunamis also.

East Asian and Western North and South American coasts experience this hazard the most.

Mitigation of Tsunamis

  • Find out if your house is in danger and know the height of your street above sea level.
  • Be familiar with warning signs
  • Make evacuation plans with more than one route and pick an elevated inland location.

3. Volcano: It is a landform at the end of a conduct or pipe which rises from below the crust and vents to the surface. volcano is usually in the form of a peak which may be cone-shaped or dome-shaped.

The margin of the pacific ocean is the area where the largest no. of active volcanoes are situated. india is not prone to this hazard. the only active volcano in india is the barren island in adman Nicobar island.
It damage human settlements and its dust injects into the atmosphere can be hazardous to aviation as the particulate matter can damage aircraft engines.

The liquid magma erupting from volcano may bury human settlements and all kinds of structures. Large areas of cultivable land may be covered by this debris and rendered uncultivable.

Mitigation of Volcanoes

  • The best way to protect oneself against harm volcanic eruptions is to move away at first warning or sign of eruption in a volcano.
  • Generally, there are signs of eruption much before the actual eruption in most volcanoes and monitoring agencies issue warnings for likely eruptions. one must follow these warnings to stay away from harm's way.

4. Cyclones: Cyclone are meteorological hazards that cause immense damages, especially near the coasts where their fury is the greatest. High wind velocity accompanied by heavy rains are the chief characteristics of these storms.

Coastal region of Andhra Pradesh, Odisha and west Bengal are among the areas that experience maximum damage due to cyclone. tropical cyclone are known by different names in different pats of the world, such as typhoons (south china sea), depressions or storm (Bay of Bengal ), and willy-willy (Australia).

Another variant of tropical storms is a tornado that typically an American storm.

Mitigation of Cyclones

  • Efforts can be made to reduce the fury of waves by creating some structure along the coast.
  • Planting mangroves along the coast.
  • An early warning system about the movement and development of cyclones must be installed.
  • Preparedness against cyclones also requires suitable measures in construction of houses.
  • Belts of trees can help in reducing wind velocities by acting as wind breakers.

5. Flood: A flood is a general and temporary condition where two or more acres of normally dry land or two or more properties are inundated by water or mudflow.

Flooding occurs most commonly from heavy rainfall when natural water source do not have the capacity to convey excess water. however, floods are not always caused by heavy rainfall.

They can result from other phenomena, particularly in coastal areas where inundation can be caused by a storm surge associated with a tropical cyclone.

Mitigation of Floods:

  • Aforestation can check the frequency and intensity of floods.
  • Flood can be prevented by making embankments and dykes.
  • Monitoring of the flow of water in the rivers during the rainy season and timely warning to people and evacuation of those areas can help in reducing the damages caused by floods,.
  • preparedness for such disasters and good communication networks can help reduce damages due to floods significantly.

6. Drought: It is an event that results from lower than normal expected rainfall over a season or period. the low rainfall is insufficient to meet the needs of human beings, plants, animals and agriculture.

shortfall in rainwater results in drying of rivers, lakes, reservoirs and drying of wells due to excessive withdrawal and poor recharge of groundwater and loss of crop yield due to shortage of water are some of the main indicators of  drought.

Mitigation of Drought

  • A regular monitoring of rainfall, water availability in reservoirs, lakes and rivers.
  • use of efficient methods of irrigation and sowing low water consuming crops are some important measures to overcome drought.
  • Rain water harvesting increases the water availability.

7. Cloudburst: A cloudburst is an extreme amount of precipitation in a short period of time, sometimes accompanied by hail and thunder, which is capable of creating flood conditions.
The term cloudburst arose the notion that clouds were akin to water balloons and cloud burst resulting in raid precipitation.
Uttarakhand is one of the example for seeing cloudbursts, causing death of thousands of people.

Mitigation of Cloudbursts

  • To organise a cloudburst master plan coupled with containerisation plan.
  • To build the canals and combined these canals with sewer system to level out the excess rainfall.
  • To cope with the effects of climate change and chiefly aims at fixing acceptable limits of flooding on the street.

8. Landslide: Landslides are a hazard in the mountainous regions. 
A landslide is a rapid down slope movement of rocks and soil along with vegetation growing there.
They occur in large numbers in mountain areas especially in the rainy season. The soil and rocks become saturated with water in rainy season and become heavier.
Landslides may be triggered by earthquake also. they may destroy not only forests and settlements in their path, they might cover large tracts of cultivated land with debris.

Mitigation of landslides

  • Techniques of slope stabilisation can help in checking the occurrence of landslides
  • landslide prone zones along highways etc, can be identified an structures like retaining walls can be constructed to prevent movement of rocks.
  • Maintaining a good tree cover on mountains can also help in checking the frequency of landslides.

9. Avalanches: A avalanche is a down-slope movement of snow and rocks similar to fall of debris in a landslide. however, avalanches are a hazard confined to high altitude areas where large amounts of snow accumulate.
Though, many such movements of ice result from accumulation of large amounts of snow on steep slopes and movement there of under gravity, some are triggered by factors like earthquakes, large mases of snow thus move at very high velocity and bury settlements and vegetation in their path.

Mitigation of Avalanches

  • Monitoring the amount of snow accumulation on steep slopes and development of any cracks therein can be checked and precaution can be taken to continue the likely damage.
  • Planning and creation of any infrastructure or settlement in such areas should take into account the extent of this hazard.
10. Forest Fires: They are a very common hazard in forested areas. since, there is a l large amount of combustible material in the forest, the forest fires spread to large areas very rapidly.
Some of the forest fire may be caused due to natural reasons such as friction between trees and lightening, more of them are a result of human activities

Forest fires after become difficult to control any endanger infrastructure and habitations.

Mitigation of Forest Fires

  • To keep a vigil in forest areas against fire.
  • To maintain fire lines in forest is very important
  • Scientific methods should be employed to control fire in forest areas whenever such an event occurs so that the damage is maintained and confined to the smallest possible area.

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