P1 The Challenge Of Natural Hazards Flashcards
Definition of a natural hazard
A natural event that threatens people or has the potential to cause damage destruction or death
4 examples of tectonic hazards
Earthquake
Volcanic eruption
Landslides
Tsunami
2 types of geomorphological hazards
Floods,landslides
3 types of atmospheric hazards
Tropical storms
Droughts
Tornadoes
2 types of biological hazard
Pests
Diseases
Factors affecting hazard risk(and why)
- Population density, more people live in high risk areas as it is cheaper and they cant afford to move away
- Frequency and magnitude
- Wealth as hic’s are more prepared and able to cope than lic’s and nee-hics have strict construction laws in hazardous areas
- Climate change as rising temps can cause drought and tropical storms and wetter conditions can cause floods
- Human activities such as urbanisation and deforestation
What causes convection currents in the mantle
Hot core causes magma to rise in the mantle and sink when it cools,convection builds pressure and carries plates with it.
Explain the process of ridge push and what boundary it occurs at
- Magma rises as the plates move apart at constructive plate margins
- magma cools to form new plate material
- as it cools it becomes denser and slides down away from ridge
- this causes tectonic plates to move away from each other
Explain the process of slab pull and which plate boundary it occurs at
- Two plates converge towards each other at destructive plate margins
- Where the denser oceanic crust subducts under the continental crust
due to gravity pulling the rest of the plate with it
Global distribution of earthquakes and volcanic eruptions in relation to plate margins
-NOT random
-they occur on narrow bands along plate margins
-found on land AND sea
-earthquakes found at all 4: constructive,destructive,collision,conservative
-anomalies occur at hotspots where the crust is thinner
Physical processes that occur at constructive plate boundaries and an example
Example-Eurasian and North American plates
Hot molten magma rises between the plates
Tectonic plates move away from each other due to ridge push
Magma cools to form a new plate
This is where land rift valleys form
Physical processes that occur at destructive plate boundaries(+ example)
(Example:pacific and Philippine plates)
- Where tectonic plates converge, pressure builds between them
- the rock eventually fractures(causing earthquakes)
- when oceanic and continental plates collide,the denser oceanic plate is subducted,under the continental plate and into the mantle where it melts
- hot magma can rise through the lithosphere and erupt as lava through (cone)volcanoes
Give a named example of a tropical storm
Tropical storm Haiyan
What date did tropical storm haiyan happen?
8th November 2013
Where’re did tropical storm haiyan occur
The Philippines
describe the formation of a tropical storm
1) the suns incoming solar radiation to earth warms our oceans especially at the tropics
2) this warms the ocean to a criticle 27 degrees or above
3) this causes moist air to rise through the air in thermals, this gives low pressure at the cetre of the storm
4) this air cools as it rises causing cindensation to occur clouds to form and precipitation fall
5) some cool air sinks back diwn helping to create the eye
6) air rushes in from higher pressure areas outside of the storm to lower pressure areas at the centre ,creating winds.
7) the whole storm rotates because of the earthspin
What were the causes of tropical storm haiyan?
.water evaporates from the ocean
.most people live vulnerably along the coast and are unaware of the surge
.rising sea levels
What is a surface wind
Caused by air rushing from areas of high pressure to areas of low pressure
What is a pressure belt
These are caused by cool air sinking in some areas resulting in a belt of high pressure. Warm air rises in areas resulting in a belt of of low pressure.
Physical processes that occur at conservative plate boundaries(+example)
(Example:pacific and North American plates)
-sliding parallel past each other at different directions or at different speeds
-pressure builds at the margin of the tectonic plates as they are pulled along behind a plate subducted else where
-as friction is overcome rock fractures in an earthquake