What is a hazard
An event that has the potential to cause damage or destruction to people their property and settlements
What is a natural hazard
An event produced by environmental processes that has the potential to cause damage or destruction to people their property and settlements
What is a disatser
a sudden accident or a natural hazard that causes great damage or loss of life, environmental degradation and or socio - economic desruption
What is risk
The probability of a hazard event causing harmful consequences
What is vulnerability
The geographic conditions that increase the susceptibility of a community to a hazard or the impacts of a hazardous event
What is a tropical storm
a rapidly rotating storm that begins over tropical oceans and they can vary in speed size and intensity
What is the coriolis effect
The deflective force caused by the earths rotating that causes developing storms to spin
What is wind sheer
The change in direction or speed of winds over the surface of the ocean
What is the saffir - Simpson scale
a 1-5 rating of hurricanes based on sustained wind speed at that time
What is the eye
a region of 20 - 50 km in diameter found at the centre of a storm where skies are often clear winds are light
What is the eye wall
a ring of cumulonimbus clouds that swirl around the eye. The heaviest precipitation and strongest winds are found here
What is a storm surge
Increase in ocean water levels above normally dry land that results when a tropical storm lands land fall
What are the four types of natural hazards
Geological - earthquake, volcanoes
Cliimatic - cyclones, droughts
Biological - fire, diseases
Technological - pollution, nuclear explosion
Explain why tropical cyclones form over warm oceans but never over cold oceans or land
- they use the warm oceans for energy which acts as fuel for the hurricanes
- as water evaporates from the tropical oceans it rises and condenses, this change from water vapour to liquid water releases energy
- over cold water the tropical cyclones do not have sufficient energy causing them to dissipate
What factors cause a cyclone to dissipate and why do they tend to weaken once hitting land
- landfall - cyclones lose energy as it loses its primary fuel source, warm water
- cold water below 26.5 degrees c
- encountering other weather systems with winds blowing in different directions, disrupting the cyclones structure
What is another name for constructive plate boundaries
Divergent
Explain what happens at a constructive plate margin
- the plates move apart from eachother
- this causes magma from the mantle to rise up to make (construct) new land in the form of a shield volcano
What is formed at a constructive plate margin
- chains of underwater volcanoes
- volcanic islands
- earthquakes
- shield volcanos
- mid ocean ridges
- rift valley
What is another name for a conservative plate margin
Passive or transform plate margin
What happens at a conservative plate margin
- The plates slide past eachother or are side by side moving at different speeds
- as plates move friction occurs and plates become stuck, pressure builds up because the plates are still trying to move
- when the pressure is released, it sends out huge amounts of energy causing an earthquake
What landforms are formed at a conservative plate margin
- very destructive earthquakes
- NO VOLCANOES
What is another name for a destructive plate margin
Convergent
What happens at an oceanic continental destructive plate margin
-When an oceanic and continental plate move towards eachother the heavier denser oceanic plate subducts the lighter, thicker continental plate
-when t epilate sinks into the mantle it melts to form magma
- the pressure of the magma builds up beneath the earths surface, which then escapes through weaknesses in the rock and rises up to form a composite volcano
What is formed at an oceanic continental destructive plate margin
- earthquakes
- ocean trench
- composite volcano
