P1A - The Challenge of Natural Hazards

The Challenge of Natural Hazards

Types of natural hazards (4)

tectonic (earthquakes, tsunamis)

atmospheric (tropical storms)

geomorphological (flooding)

biological (forest fires)

factors affecting hazard risk (2)

wealth

population growth

why do people live near hazardous areas (4)

can’t accurately predict - location, magnitude, timing.

can’t move - poverty or lack of knowledge

its worth staying - resources or jobs

don’t want to go - overconfident in defences or optimistic it won’t happen or cultural or generational ties

oceanic crust is … (5)

thinner (5-10km)

more dense

formed of basaltic rock

sinks when it meets continental plate

usually less than 200 million year old

continental crust is … (3)

thicker (20-200km)

composed mainly of granite rock

up to 3.8 billion years old

how do tectonic plates move (2)

convection

ridge push and slab pull

what is convection

magma rises in the mantle

as it rises from the core it get pushed to the side, cools and sinks

convection currents flowing in the mantle carry plates with them

what is ridge push (6)

ocean ridges are tall, raised areas on the ocean floor

hot magma melts beneath these ridges

magma rises and cools to form new crust

as new crust cools it becomes heavier

heavier crust slides away from the ridge

sliding motion pushes plates apart

what is slab pull

at destructive plate boundaries one plate is denser than the other

denser plate sinks into mantle

as it sinks it pulls the rest of the plate with it

what happens at constructive plate margins

tectonic plates move apart

releases pressure

molten magma rises between them

cools down to form solid rock

as rock cools, it becomes denser and sinks

this causes the tectonic plates to move further apart

what type of volcanoes do constructive plate margins create

shield volcanoes which have wide base and gentle slopes

what is a real life example of what is created along a constructive plate margin

the mid atlantic ridge in iceland

what are rift valleys

steep sided valleys

formed at constructive plate margins

what happens at destructive plate margins

tectonic plates moves towards each other and collide

if it is 2 continental plates

• they are both buyant and cannot sink

• therefore compression forces the plates to collide and form mountains

if it is a continental plate and an oceanic plate

• the denser oceanic plate is subducted and sinks under the continental plate

• causing earthquakes, fold mountains, and volcanoes

what is a real life example of what is created along a destructive plate margin

Japan’s volcanoes

• Japan lies on a destructive plate margin

• the ring of fire

what happens at conservative plate margins

tectonic plates move parallel to each other

pressure might build up

pressure is released, sending out huge amount of energy causing an earthquake

magma cannot rise as no gap was created therefore volcanoes are not found here

what is a real life example of what is created along a conservative plate margin

San Andreas Fault

800km

through the state of california

what happens at collision plate margins

2 continental plates meet and collide

they buckle up and form fold mountains

pressure builds up

pressure releases causing earthquakes

here no volcanoes are found

what is a real life example of what is created along a collision plate margin

The Himalayas are fold mountains squeezed between the Indo-Australian plate and the Eurasian plate

why do people continue to live in hazardous areas

• geothermal energy

• farming

• mining

• tourism

• family, friends, feelings and freedom

what are 4 factors that aim to reduce the damage that earthquakes and volcanic eruptions cause

• monitoring

• prediction

• protection

• planning

how do people monitor and predict hazards (4)

seismologists use radon detection devices to measure radon gas in the soil and groundwater

sensitive seismometers are used to measure tremors or foreshocks

earthquake locations are mapped to spot patterns and predict

smart phones have GPS (global positioning system) which can detect movements in the ground which are analysed to warn others further away

how do people protect people from hazards

designing buildings and roads and bridges to withstand earthquakes

how do people plan for hazards (5)

Furniture and objects can be fastened down

residents learn how to turn off the main gas, electricity and water supplies

emergency aid supplies

On 1st September each year, Japan practices earthquake drills on National Training Day, which marks the anniversary of the Tokyo earthquake in 1923 which killed 156, 000 people

American red cross provides earthquake safety checklists

why is it hotter at the equator

sun’s rays are more concentrated

the same amount of thermal energy is acting on a smaller area

draw the atmospheric circulation model

where is the hadley cell found

0°-30° latitude on both sides of the equator

where is the ferrel cell found

30°-60° latitude

where is the polar cell found

60°-90° latitude

what happens at the hadley cell (3)

warm air rises at the equator in an area of low pressure

rising air cools and spreads polewards

air sinks at 0°-30° latitude created areas of high pressure

what happens at the ferrel cell (3)

acts as a link between the hadley and the polar cells

air rises at 60° in areas of low pressure and sinks at 30° in areas of high pressure

produces westerly winds

what happens at the polar cell

cold dense air sinks at the poles in areas of high pressure

air moves towards 60°

air warms and rises in areas of low pressure

produces polar easterlies

what type of climates are at the hadley cell

hot

dry

sahara desert, arabian desert

what type of climates are at the ferrel cell

wet

windy

uk climate

what type of climates are at the polar cell

cold

dry

tundra like

what is a tropical storm

a destructive storm that occurs between the tropic of cancer and the tropic of capricorn

where do they call tropical storms hurricanes

atlantic and eastern pacific

where do they call tropical storms cyclones

indian and south pacific

where do they call tropical storms typhoons

north pacific

do tropical storms occur in areas of high or low pressure

low pressure

conditions needed for a tropical storm to occur (3)

an ocean depth of at least 70m

at least 5°-15° north or south the equator

sea temperature of over 26.5°C

How does a tropical storm form (12)

air is heated above the surface of warm tropical oceans

warm air rises rapidly under the low pressure conditions

rising air draws up more air and large volumes of moisture

causing strong winds

coriolis effect causes the air to spin upwards around a calm centre eye of the storm

as the air rises it cools and condenses to form large towering cumulonimbus clouds

generates torrential rainfall

heat given off when air cools powers the storm

cold air sinks in the eye

so in the eye is it drier and much calmer

tropical storms travel across the ocean in the prevailling wind

when a tropical storm meets the land it is no longer fuelled by the source of moisture and it loses power and weakens

characteristics of tropical storms (5)

strong winds

anticlockwise spin

storm surges

low air pressure

heavy rainfall

features of tropical storms (3)

thick cloud

eye of the storm

eye wall

how might climate change affect tropical storms

higher storm surges

increased heavy rainfall

more destructive flooding

how are tropical storms monitered

satellites

aircraft

how can tropical storms be predicted

in 2013 the national oceanic supercomputers now can give 5 days warning and have a more accurate location of 400km

what kinds of weather events affect the uk (4)

storm events

flooding

droughts

heatwaves

what is the evidence for climate change

ice cores

ocean sediments

what are ice cores

forms of layers of ice

they are drilled

the deeper the ice is drilled the older the snow

records go back to about 800, 000 years ago

natural factors of climate change

solar energy output

orbital changes

volcanic activity

how do humans cause climate change

fossil fuels

agriculture

deforestation

environmental effects of climate change (5)

rising sea levels

more extreme weather events

melting glaciers

loss of biodiversity

ocean acidification

social effects of climate change (5)

increased health risks - spread of diseases like malaria as mosquitos thrive in warmer climates

food insecurity

water shortages

displacement and migration

The fishing industry in east asia is expected to decrease due to sea increasing in pH and acidity

how can the causes of climate change be reduced (4) (explain how IRL)

alternative energy production

carbon capture

planting trees

international agreements

how can climate change be managed through adaptation

change in agricultural systems

• moving production

• increase irrigation in areas

• changing crops and the time of year they are planted

managing water supply

• reducing demand

• increasing supply