Hazardous earth Flashcards
Oceanic vs continental crust
continental froms on land and is mostly made out of granite which is a low density igneuous rock it is also much thicker.
Oceanic crust-forms under the ocean. it is much thinner and is much denser. Formed out of the igneous rock basalt
What are the different layers of the earth in order
lithosphere(consists of crust), mantle(asthenosphere then lower mantle), outer core,inner core
Explain the properties of the asthenosphere
partially molten and 900-1600 temp
Explain the properties of the lower mantle
solid and 1600-4000 temp
Explain the properties of the outer core
liquid iron and nickle 4000-5000
Explain the properties of the inner core
solid iron and around 5200 temp
Destructive plate boundary
Collision plate boundaries
Divergant plate boundary
Conservative plate boundary
Explain convection currents
causes plates to move
What are plumes?
part of convection current where the heat is rising. Concentrated zone of heat where the crust is weakened and volcanoes can occur.
What is the evidence for continental drift?
fossil evidence and places like india looking like they were once part of a larger body of land
What is subduction?
denser oceanic crsut sinks below continental crust at a convergent plate boundary. THhe subducted crust melts and new crust is formed at divergent plate boundaries which means the age of the crust varies greatly.
What are tectonic hazards?
natural hazards caused by the movement of the earths plates that effect people and property
Explain the features of a volcano
Composite volcanoes
Shield volcanoes
What do the richter scale and volcanic scale go up in?
time by 10 each time
What is the volcanic explosivity index?
measures the explosivity of volcanic eruptions on a scale of 1-8. It looks at the level of material ejected by the volcano and the scale is logarithmic
Explain a map of an earthquake
What is the Richter scale?
The strength or magnitude of an earthquake is measured using the Richter scale. The Richtor scale is numbered 0-10. It is a logarithmic scale..
Explain the process of an earthquake
- movement of the earth’s tectonic plates
- concentrated along fault lines(fractures in earths crust)
- Friction builds up along plate boundaries as they move against eachother until finally the energy is released
- This energy is sent out as seismic waves
How can earthquakes be protected against?
building designs and early warning systems.
What is a tsunami?
earthquakes beneath the sea bed can generate tsunami waves that aproach the coast and get bigger as the friction slows them down(shallow water)
How are tsunamis formed?
How is the suns energy concentrated?
mostly at equator and least concentrated at the poles. This is because it strikes the equator directly but at a low angle. This differenc in energy os redistributed by air pressure differences and ocean currents. This makes the world habitable.
What is the global atmospheric circulation
What is the hadley cell
warm air rises at the equator creating low pressure, this air goes outwards and then sinks creating high pressure
What is the ferrel cell
sinked air from hadley cell goes more outwards to 60 rather than 30 and then heats up and rises where it goes back to 30 and sinks again
What does the polar cell do
Low pressure air at 60 travels towards the poles(90) where it sinks(high pressure), This air then travels back along the surface to 60
What are ocean currents
They redistribute warm water around the equator the poles and vice versa. A good example is the Gulf stream which warms up the UK from across the atlantic in the Gulf of mexico. Parts of Canada colder but more south.
Explain air pressure
at the surface, air travels from high pressure to low pressure. This is because low preessure air rises and high pressure air sinks. As the low pressure air rises the sinking air rushes to fill the the gaps. This movement of air creates wind and spreads heat across the surface
High pressure
no cloud formation and calm
low pressure
wind, precipitation and clouds
What is the ITCZ?
Inter-tropical convergance zone. The name for where 2 hadley cells meet. High rainfall caused by low pressure. It moves around to follow the most direct energy from the sun.
Enhanced greenhouse effect
Humans causing more greenhouse gasses to be added to the atmosphere than natural
Climate graphs
average precipitation and temp for each month in a year for a location.
line graph=temp
bar graph=precipitation
What is the evidence for past climate change
Ice cores – contains bubbles of the atmosphere trapped up to 400,000 years ago. We can see the CO2 concentrations and infer the temperature. Long term evidence but only from areas where there is ice.
Tree rings – the rings on a tree represent a year of growth. The thickness of the ring can tell us a lot about the climate. Thicker rings mean better growing conditions (warmer and wetter) detailed but shorter term
Historical sources- historical paintings and diary records can give us insights about the past climates however these can be subjective and not always reliable.
what wind speeds in mph isa hurricane?
74mph
Where do tropical cyclones develop?
large, still warm ocean with a surface temp above 26.5 degrees over long periods. Form in late summer.
Strong winds in troposphere around 10-12km above the earths surface
A strong force created by the eraths rotation called corriolis force
do not form near the equator. Between 5 and 30 degrees latitude
Map
What scale is used to measure tropical cyclones?
saffir simpson scale
What hazards do tropical cyclones bring?
strong winds
storm surges
coastal flooding
intense rainfall
landslides
Describe the process of a tropical cyclone forming
- warm air currents rise from the ocean, as it rises more air rushes to replace it
- updraughts of air contain huge volumes of water vapour from the oceans which condense to produce cumolonimbus clouds
- coriolis force causes rising currents of air ti spiral around the centre of the tropical cyclone so it resembles a whirling cylinder. Some of it descends to form the clear, still and cloudless eye of the storm
- as it tracks away from its source it is fed new heat and moisture which makes it more powerfull
- Once it reaches a landmass it loses its energy source from the ocean. Air pressure rises as temperature falls. Winds drop, rainfall decreases and it decays to become a more storm
What was the size, date and location of the Japanese earthquake?
March 11 2011
9 magnitude earthquake
off the east coast of Japan
What were some of the long and short term impacts on people for the Japanese earthquake?
short:
15,894 people died
332,395 buildings were damaged
4.4 million households left with no electricity
long:
economy(cost 235 billionUSD)
Japans transport network suffor huge disruptions
tsunami
What were some of the short and long term environmental impacts of the Japan earthquake?
short:
land fall
tsunami that was 40m high
800 earthquakes of 4.5 or more were recorded following the main one
long:
plate shifts(pacific plate shifted 20 to 40 metres west)
250 mile stretch of coast dropped by 0.6(bad for stopping the tsunami)
land movement
What are some of the preperations for earthquakes in Japan and strategies?
rescue services and healthcare
shelter and rebuilding
tsunami barriers and international aid
earthquake prediction
earthquake proofing the buildings
warning systems
What was the size, date and location of the Haiti earthquake
12th of january 25km from the capital with a magnitude of 7
What were some of the short and long term effects for the Haiti earthquake?
230,00 deaths
250,000 dwellings destroyed
8 hospitals and presidential palace destroyed
disease and cholera outbreak due to poor sanitation
1 in 5 lost their jobs
people emigrating out of the country
responses to the Haiti earthquake
damaged port so slow
USA sent rescue team and 10,000 troops
bottled water and purification tablets provided
UK government donated 20 million pounds
Haiti became dependant on overseas aid from China and other countries
new homes built new airport built
When where and what magnitude was Hurricane katrina?
magnitude 5 that weakened to 3 at landfall in New Orleans and coastal Loisiana in august 2005.
What were the impacts of hurricane Katrina?
1,800 died
300,00 homes destroyed
300 billion USD of damage
tourism decreased
80 percent of New Orleans flooded
so crops destroyed
habitats destroyed
What were the responses
criticism
50 billion USD in aid was given by the government
UK sent food aid
national guard mobilised to restore law and order
When where and of what magnitude was cyclone aila?
Bay of bengal on 25th may 2009
What were some of the impacts of cyclone Aila?
190 people died
750,000 made homeless
crops flooded with salty water which killed the crops
by mid 2010 200,000 people still living in temporary shacks
loss of 59,00 animals
sickness and typhoid were problems
What were the responses of cyclone aila?
What were the responses of cyclone Aila?
weather forcasting(bad as not many people had access to broadcasts) did not change too much
satellite tech, did not have it prior but announced it was going to spend 150 million USD on developing their satellite technology(expensive)
warning systems increased with campaigns and posters and leaflets and film and volunteers
Evacuation strategies improved such as shelters built in coastal districts
