section A: the challenges of natural hazards

Question 1

What is a natural hazard?

Answer 1

Natural hazards= a natural environmental event that could potentially impact a person

Question 2

What’s a hazard risk?

Answer 2

Hazard risks=the chance of being affected by a natural hazard

Question 3

What’s an example of hazard risk?

Answer 3

Those living near the sea are at risk of flooding caused by tropical storms

Question 4

What factors affect risk?

Answer 4

Urbanisation-densely populated urban areas concentrate this at risk
Poverty- shortage of housing leads to building on risky ground
Farming-the attraction of fertile silt on floodplains puts people at risk
Climate change-global warming raises sea levels and generates more extreme weather

Question 5

How did plate tectonic theory develop?

Answer 5

Alfred Wegener suggested in 1912 that the continents were once joined together and then gradually floated apart

Question 6

What was the evidence for plate tectonic theory?

Answer 6

-Fossils found in parts of the continent
-fit together like a puzzle

Question 7

What are the two tectonic plates and describe them?

Answer 7

Continental-less dense, thicker and older crust
Oceanic-denser, thinner and recently formed crust

Question 8

What are the plate margins called were plates separate?

Answer 8

Constructive-plates pull apart
Destructive-oceanic plate subduct’s continental plate
Conservative-plates move in opposite directions and get stuck

Question 9

What makes tectonic plates move?

Answer 9

Conventional currents

Question 10

Describe how conventional currents works

Answer 10

Heat driven cycles that can move tectonic plates onto their side and gravitational sliding causes the tectonic plate to come back down to the ground.

Question 11

What happens at ridge push?

Answer 11

Ridge push is the result of gravitational forces acting on the raised oceanic lithosphere around mid-ocean ridges, causing it to slide down the similarly raised but weaker asthenosphere and push on lithospheric material farther from the ridges

Question 12

What happens at slab pull?

Answer 12

This is similar to a destructive plate boundary where the oceanic crust subduct’s the continual crust

Question 13

Gravitational sliding:

Answer 13

1)ridge push at divergent margins is caused by rising magma pushing part of the plate on its side
2)slab pull brings the tectonic plate downwards due to gravitational sliding

Question 14

At what two plate boundaries can ridge push and slab pull happen?

Answer 14

constructive (is ridge push) and destructive (slab pull)

Question 15

Constructive margin:

Answer 15

-when two tectonic plates pull apart usually continental plates
-magma is heated becomes less dense causing it to rise
-as it reaches the top it breaks the crust with little force and causes a mild earthquake
-the magma that erupts out of the newly created gap causes a flat shield volcano because of its low viscosity and creates flat shield volcanoes

Question 16

Destructive plate boundary:

Answer 16

-the oceanic plate subduct’s the less dense continental crust
-the continental crust remains but starts to crack
-the oceanic plate starts to melt due to friction and causes hit magma that rises and tries to fit through the cracks of the continental plate
-the magma erupts with force out through the cracks creating a strong earthquake and composite volcanoes

Question 17

Conservative plate boundary:

Answer 17

-two plates move past each other in opposite directions
-they get stuck due to friction
-as they are still trying to move it causes pressure
-this pressure is then realised as the plate slips and releases huge amounts of energy called seismic waves which causes the ground to shake

Question 18

Where do only earthquakes form?

Answer 18

Conservative

Question 19

Primary effect? Example?

Answer 19

Immediate impact- killed, made homeless , a building collapsed

Question 20

Secondary effect? Example?

Answer 20

Long term impact- diseases , lack of natural resources

Question 21

Primary response:

Answer 21

Stop and search for survivors
Receive medical treatment from other countries

Question 22

Secondary response:

Answer 22

Practise drills

Question 23

Why do people live at risk from tectonic hazards?

Answer 23

Poor people have no choice
Not seen as a great threat
Volcanoes can bring wealth from tourists and people do it for the money

Question 24

Monitoring volcanoes:
Monitoring earthquakes:

Answer 24

Scientists use science equipment such as a seismometer to detect and record micro quakes
same goes for volcanoes scientist use seismometers

Question 25

Prediction volcanoes: Prediction earthquakes:

Answer 25

Volcanoes-monitoring is now allowing accurate predictions and effective evacuations even though they still are not 100 precent sure Earthquakes- accurate predictions are impossible due to lack of clear warning signs but historical records help

Question 26

Protection volcanoes: Protection earthquakes:

Answer 26

Volcanoes - earth embankments have been used to successfully diverts lava flow Earthquakes- earthquake proof buildings

Question 27

Planning volcanoes: Planning earthquakes:

Answer 27

Volcanoes- hazard mapping is used to identify areas to control development in at risk areas Earthquakes- shakemaps are used to identify lower risk areas to locate high value buildings

Question 28

What’s global atmospheric circulation?

Answer 28

Atmospheric circulation involves a number of interconnected circular air movements called cells

Question 29

Describe atmospheric circulation:

Answer 29

-sinking cold air creates high pressure and rising warm air creates low pressure -surface winds move from high to low pressure transferring heat and moisture from one area to another -the winds curve due to the earths rotation of the earth causes relative changes in the position of the overhead sun

Question 30

How does global circulation affect the worlds weather?

Answer 30

Cloudy and wet where we live because 50-60 N is close to where cold polar air from the north meets warm subtropical air from the south.The surface winds from the south west usually brings warm and wet weather because riding air cools and condenses CHECK MORE IN TEXT BOOK PAGE 24

Question 31

What are tropical storms?

Answer 31

They are huge storms called hurricanes, cyclones and typhoons in different parts of the world

Question 32

How do they from?

Answer 32

Most form 5-15 North and south of the equator in autumn and summer where ocean temperatures are highest(above 27 degrees).The spinning (coriolis) effect of the earths rotation being very high. Intense heat and humidity make air unstable ,causing it to rise rapidly

Question 33

What is tropical storms formation affected by?

Answer 33

Global atmospheric circulation

Question 34

How does global atmospheric circulation affect tropical storms?

Answer 34

-unstable rising air in the equations, regions(where the two Hadley cells converge) encourages air to rise ,condense and from storm clouds -wind blows from high pressure belts (sub-tropical) to low (equatorial).These trade winds are responsible for the predominantly eats-west storm paths

Question 35

The structure and features of a tropical storm:

Answer 35

Winter-no -the centre of the eye -a column of rapidly sinking cool air where conditions are relatively calm and there are no clouds -at the outer edge of the eye is the eye wall-the most severe conditions with very strong winds including tornadoes and torrential rainfall -cumulonimbus clouds swirling around beyond the eye wall bring additional bands of rain

Question 36

How are tropical storms triggered?

Answer 36

The upward movement of evaporated air and moisture

Question 37

When to tropical storms stop?

Answer 37

When they reach land