CHAPTER 3: HAZARDOUS ENVIRONMENTS Flashcards
What is a hazard?
It is an event that threatens, or actually causes damage and destruction to people their property and settlements.
What is a natural hazard?
A natural hazard is one produced by environments process such as storms, floods, earthquakes and volcanic eruptions.
Why are some places are more hazardous than others?
.Some places experience more than one type of natural hazards events
. Some places experience natural hazards more frequency than others
. In some places the hazards are stronger and more destructive than in others
. Some places are better able to cope with the damaging impacts of natural hazards
What are the four main Hazard categories ?
.Geological
.Climatic
.Biological
.Technological
What are the Hazards created by people (Technological) ?
.Nuclear explosion
. Pollution
. Transport accident
. Industrial explosions
Important point
The important point to remember is that if there were no people there would be no natural hazards - just natural events.
What are the events created by Geological Hazards ?
. Earthquakes
.Volcanic eruptions
.Landslides
What are the events created by Climatic Hazards?
.Storms
.Floods
.Droughts
What are the events created by Biological Hazard ?
.Fires
.Pests
.Diseases
What is Geological Hazards ?
It is when all the events happening in the crust of the earth for example Tsunamis, Volcanos, earthquakes.
They can also be very destructive and aggressive causing damage and harm towards the people , buildings and surroundings.
What is Climate Hazards ?
They are the hazards which threatens the health of any organism, known as biological hazard.
They can cause events such to can cause disasters to humans and their settlements due to climatic (weather) factors and change for example floods, Droughts, storms and tropical cyclones.
What is Biological Hazards ?
Biological Hazards are formed to affect an organism health for example diseases such as cold, flu, malaria , dengue etc and even caused through pests and diseases.
Causes of floods ?
- They are not only caused by heavy rainfall of a tropical cyclone.
- where as a stream of volcanic lava running down the valley can
easily block the river can cause flooding upstream. - Floods in the costal area can caused by tilde waves, for example
tsunamis associated with earthquakes. - storm surges can be caused by flooding.
What are the natural events caused by indirect Hazards ?
- Droughts becomes hazards mainly because of its effect on food
production. - Crops and livestock which lack water will not yield so much food.
- Food shortages mean malnutrition and possibly death by
starvation.
Are diseases natural events or are they caused by humans?
- Malaria is a ‘vector’ or biological hazard carried from humans to the
next by a mosquito.
There many contagious diseases associated with human pollution of the environment. (Typhoid and cholera are just two examples.)
- An interesting aspect of all disease is that hazard threat is very focused on people. The outcomes are illness and death for people.
- Tropical cyclones are a climate hazard in which two weather elements, wind and rain, threaten human life and property.
- Earthquakes and volcanic eruptions are geological or tectonic hazards.
How does Tropical cyclones starts?
- A tropical cyclone starts when high temperatures cause air to rise
from the surface of the sea. - The rising causes local thunderstorms.
- Occasionally these small storms come together and create a
strong flow of warm. - Later air would rapidly rise.
- Producing an area increasingly low pressure.
(refer the diagram in pg 67)
What are the number conditions that have to be met if these local thunderstorms are to be developed ?
-A deep layer of humid with warm and unstable air (>27 degrees)
- a supply of energy from the surface of the sea (the energy would
have to be heat and moisture)
-The sea must be at its warmest
- A circulatory motion of air (anti- clockwise in the northern
hemisphere encourage by the Coriolis force )
- Small changes in the wind speed and directions with increasing
altitudes. (encourages the circulatory motion within the cyclone)
Key word : Coriolis force - (its when the force created by the earths rotation that deflects any object moving at the earth surfaces.)
What are the physical features of a cyclone ?
- it rotates vigorously upwards in the spiral of humid.
- warm air at its very center of its eye.
- There is an area of subsiding air with calm conditions and clear
skies. - Surroundings the eye is the eye wall, where the most destructive
energy of the cyclone occurs.
What is the global distribution of tropical cyclones?
STUDY FIGURE 3.4 IN PG 68
