The challenge of natural hazards Flashcards
What is a natural hazard?
A natural hazard is a natural event that poses a risk to people and property
What are the types of natural hazards?
Tectonic, Geomorphological, Atmospheric, Biological
3 factors that affect the risk hazard
-vulnerability
-capacity to cope
-nature of natural hazard
What is the basics of the plate continental theory?
The earth was one big supercontinent called Pangaea. Continents began to drift apart 300 million yrs ago(continental drift theory)
2 pieces of evidence for the plate tectonic theory?
-fossils
-theory of convection currents: convection currents in the earths mantle caused the plates 2 move
where are earthquakes found?
along all types of plate margins
where do volcanic eruptions occur
-only @ constructive and destructive plate margins
-ring of fire:plate margin of the pacific plate
what happens at a constructive plate margins?
plates are moving away (volcanic eruptions and earthquakes)
example of a constructive plate margin
mid-Atlantic ridge
what happens at a destructive plate margin
-plates are moving 2gether
-oceanic plate subducted under continental
-volcanic eruptions and earthquakes
example of a destructive plate margin
boundary btwn nazca + south american plate
what happens at a conservative plate boundary
-plates move past each other in opposite directions+ different speeds
-only earthquakes
Reasons why people live in areas of tectonic risk.
-can’t move
-concern of their economic stability
-cheap geothermal energy
-magma is mineral rich
-overconfident
3 ways monitoring and planning can can reduce risk
-possible to predict general location of earthquake so evacuation means less people injured
-seismometers used to measure foreshocks
-radon detectors can be used to measure radon gas in cracks in the earths surface
2 ways protection can be done 2 reduce risk
-cross bracing: buildings are reinforced with steel across to provide structural support
-Base isolation: foundation absorbs seismc ssocks
2 ways planning reduces risk
-fasten down furniture
-earthquake drills
What does global atmospheric circulation explain
-location of world climste zones and distribution of weather hazards
Air sinking= pressure, wind direction
-high pressure
-winds moving outwards 30° N & S poles
Air rising= pressure, wind direction
-low pressure
-0°-60° N & S
Coriolis effect on wind
winds are distorted by earths rotation
Surface winds transfer. . .
. . .heat and moisture from one place to another leading to differing weather
Where are Hadley cells located?
Around either side of the equator
Do Hadley cells receive sunlight?
Hadley cells receive intense sunlight from the sun
What is pressure like at a hadley cell?
rising air = low pressure
What is the weather like around a Hadley cell?
-rising air cools to form clouds
-hot humid weather 4rom heavy rainfall
What are trade winds
air that flows back to the equator
what climate is at 0°
tropical climate
what climate is at 30°
desert climate
where is a Ferrel cell found
30°- 60° N&S of the equator
What type of cell causes UK weather
Ferrel cell
ferrel cells wind
-wind travels across oceans so pick up moisture
-warm air from tropics/ cold air from poles
-warm air rises above cold causing low pressure
cold air is __________ than hot air
denser
polar cells wind
flows towards equator
Where are tropical storms formed?
tropics as warm oceans are needed
how many degrees from the equator
5°-15° N&S of equator
heat and spin effect in tropical regions
-intense heat causes rapid air rise
-enough spin from the earths rotation to transfer unstable air into a rotating storm
What is the zone between the two Hadley cells called?
Inter tropical convergence zone
strong tropical storms need:
________ winds
________ spin
________ pressure
great winds, great spin, low pressure
