Hazardous Environments Flashcards
Natural Hazard Definition
A physical event which has the potential to threaten lives, property and the environment
Natural Disaster Definition
A physical event which actually causes damage or destruction to people, property, settlements and the environment.
Natural Event Definition
Something happening in the physical environment, such as a storm, volcanic eruption
Types of Geological Natural Hazards
- Earthquakes
- Tsunamis
- Volcanic Eruptions
- Landslides
Types of Climatic Natural Hazards
- Cyclones/Hurricanes
- Flooding
- Tornadoes
- Droughts
Names for cyclones in different areas
Hurricanes = Americas
Cyclones = India, Africa, Oceania
Typhoons = Japan
Features of Cyclones
Eye - in the middle of cyclone
Eyewall - clouds around the eye
Vortex - central spiral
Cumulonimbus clouds - large clouds filled with water
Frequency of Cyclone Occurrences
North America - 2 annually
Australia - 11 annually
India/Bangladesh - 3 annually
Japan - 20/30 annually
Difference between frequency and Intensity of Cyclones
Frequency = how often the cyclones annually - how many landfalls are made - measure per cyclone annually
Intensity = How strong the cyclone is - measured in windspeed -
118–165 km/h
166–212 km/h
greater than 212 km/h
Cyclone Track
Winds swirl around a central region of low atmospheric pressure. It moves in the direction of the earths rotation. It will build up over the ocean and eventually make landfall where it will decrease in intensity slowly.
How do cyclone change when they makes landfall?
There is a difference in friction from the sea to the land.
Hazard Risk
The probability of a hazard event causing harmful consequences.
Hazard Vulnerability
The ability of the population to prepare and cope with the natural hazards.
6 Factors which affect Cyclones - what is necessary?
- Consistent high temperatures (solar radiation)
- Sea temp higher than 26.5 Celsius
- Sea depth below 70m
- Low atmospheric pressure
- Low wind shear - lower and upper blow in same direction
- Time of year when all is present.
Classification of Impacts of Cyclones
-Amount of damage
-Ability to rebuild from that damage
-Duration
-Magnitude
-Scale
-Direct/indirect effects
Physical Hazards of Cyclones
- Very strong winds
- Torrential rain
- Storm Surges
Direct effects of Cyclones
Death by storm surges
Death by immediate collapse of buildings
Indirect effects of Cyclones
Death by diseases
What is the scale called to measure Cyclones
Saffir-Simpson
Levels of the Saffir-Simpson scale
1) 119-153 km/h
2) 154-177 km/h
3) 178-208 km/h
4) 209-251 km/h
5) greater than 252km/h
When was Cyclone Idai
14th March -> 21st March
Which countries were affect by Cyclone Idai
Mozambique, Zimbabwe, Malawi
Death caused by Cyclone Idai
1,000 killed
Number of those displaced by Cyclone Idai
400,000 homeless/displaced
What did Cyclone Idai cause
Extreme flooding
5,800 cases of cholera
10,600+ cases of malaria
What magnitude was Cyclone Idai
4 at landfall
Deadliest tropical cyclone in the south-west Indian Ocean
How much monetary damage did Cyclone Idai cause
$3.3 Billion
LIC’s = hard to respond
Physical Aspects damaged by Cyclone Idai
177km/h winds
6 meter high storm surges
Floods covered 3,000 sq/km
90% of Beira destroyed
Why do people live in a Cyclone Risk area?
Fatalists - if it happens, it happens and they will deal with it.
There are good opportunities in that area which out weigh the risk of cyclones.
