Paper 1 - global hazards Flashcards
What is the epicentre of an earthquake?
the point on the Earth’s surface directly above the focus
What is the focus of an earthquake?
the point inside of the Earth’s crust where the earthquake originates
What is the ‘depth of focus’ of an earthquake?
The depth at which an earthquake occurs (distance from focus to epicentre
What is an example of a composite volcano?
Mount Fuji, Japan
What plate boundary do composite volcano’s form?
Destructive
Compare the eruptions of composite and shield volcanos
Composite volcanoes have more violent but with longer periods between them, where shield volcanos have more frequent eruptions which are less violent
What is an example of a shield volcano?
Mouna Loa, Hawaii
What plate boundary do shield volcanos form?
Constructive
What plate boundary do Fissures form?
Constructive - on fault lines
What is an example of a fissure volcano
The mid-atlantic ridge
What is the lava like in a fissure volcano?
Basaltic lava - hard, volcanic rock
What is extreme weather?
When weather is significantly different tot he norm, depends on where you are
What is the definition of a drought?
A period of time when an area has significantly less water than the norm
What are the 4 types of drought?
Meteorological, agricultural, hydrological and water supply
What is a Meteorological drought?
Lack of rain
What is an agricultural drought?
Low levels of water in soil
What is a hydrological drought?
Low levels of water in rivers and lakes
What is a water-supply drought?
When a drought has an impact on water supply and certain uses are prioritised.
What is the distribution of drought?
Mainly occur in South America, North-Africa, the Middle East and Australia.
What is water stress?
where the demand for water exceeds supply
What is water scarcity?
a limit in availability due to physical shortages or failure of institutions to provide
What is a water shortage?
the lack of sufficient water resources, including lack of safe drinking water
What are the 3 main characteristics of a tropical storm?
Sustained winds (above 120km/h), Torrential rain and storm surges
What are the necessary conditions for a tropical storm?
Ocean temperature above 27 degrees Celsius,
at least 500 km from equator (for Coriolis spin system) and ocean depth over 60m.
Why are these the necessary conditions for a tropical storm?
The storm energy comes from the moist sea air
How do tropical storms form?
When ocean temps are over 27 Degrees (C), warm air rises, creating a low pressure area
More warm air is drawn upwards creating strong winds
Air cools and sinks, water vapour condenses and forms cumulonimbus clouds which form the eye of the storm
The storm eventually dies down when t reaches land as it will on longer get energy from moist sea air
What is the troposphere?
the lowest layer of the atmosphere where weather takes place
What are the 3 cells in the tri-cellular model?
Hadley, Ferrel and Polar
What happens in the Hadley cell?
convectional moist air rises at equator (sunshine overhead), air rises, reaches tropopuase and spreads towards pole. At 30 degrees latitude, the air descends (high pressure) creating trade winds.
What happens at the Ferrel cell?
This is the ‘zone of mixing’ which is driven by the other 2 cells
What happens in the Polar cell?
At 60 degrees North or south, air is almost warm enough to rise. This air spreads to pole at tropopause, air becomes very cools and sinks, spreading outwards from pole
What are the 4 layers of the Earth’s structure?
Inner core, outer core, mantle and crust
What is the inner core made out of?
Solid iron and nickel
What is the outer core made out of?
Liquid iron and nickel
What is the mantle made out of?
Semi-molten rock
What is the crust made out of?
Solid rock - tectonic plates
What are the two types of tectonic plate?
Continental and oceanic
Describe the continental plate
Less dense and thicker
Describe the oceanic plate
More dense, newer and thinner
What are convection currents?
the process in the mantle which moves tectonic plates
How hot is the mantle?
3000 degrees Celsius
What is the process in convection currents?
hot magma rises, cools and sinks
What are the 2 types of constructive plate boundaries?
Constructive and conservative
What are the 2 types of destructive plate boundaries?
subduction and collision
What happens at a constructive boundary?
2 of the same plate move away from each other, allowing magma to flow through the gap to the surface - creating volcanoes and earthquakes
What happens at a conservative boundary?
2 plates moving at different speeds move alongside each other (same of different directions) - creating violent earthquakes
What happens at a subduction zone boundary?
Oceanic plate is forced under continental plate (as it is more dense), the friction causing earthquake activity. Magma breaks continental plate and rises, creating volcanoes
What happens at a collision boundary?
2 continental plates (not dense) move towards eachother - creating fold mountains and earthquakes.
How do caldera volcanoes form?
When a volcano erupts and the magma chamber collapses, the crater falls in on itself - this is a caldera. A new volcano will eventually form as new magma rises.
What is an example of a caldera?
Crater lake, Oregon
How do hotspot volcanoes form?
Hot magma rises up towards crust and forces its way through, this then erupts to surface and causes volcanic islands.
What is an example of a hotspot?
Hawaii
During El Niño, where is the area of high pressure?
Australia
During El Niño, where is the area of low pressure?
South America
During El Niño, What direction are trade winds blowing?
West to East
During El Niño, Where has heavy rainfall?
South America
During El Niño, Where has drought?
Australia
During La Niña, where is the area of high pressure?
South America
During La Niña, where is the area of low pressure?
Australia
During La Niña, what direction are trade winds blowing?
East to West
During La Niña, Where has drought?
South America
During La Niña, Where has heavy rainfall?
Australia
What is the Walker cell?
Normal conditions
How are the walker cell and La Niña related?
La niña is a stronger version of the walker cell
How are the walker cell and El Niño related?
El Niño is the opposite of the walker cell
What is El Niño?
A period of large-scale warming of the pacific ocean
What is La Niña?
A period of below-average temperatures of the pacific ocean
What is an example of technological mitigation in Japan?
The power to trains is cut off when an earthquake is detected
What were the main causes of the Haiti Earthquake?
Shallow focus - more energy when ti reaches surface; conservative boundary;
plates sliding past each other got caught and jolted apart
When was the Haiti Earthquake?
12/1/2010
What was the magnitude of the Haiti EQ?
7.0
How many aftershocks were there in the Haiti EQ?
33
What is Haiti’s development like?
LIDC, poorest country in Western hemisphere, 80% of population live in abject poverty, life expectancy= 65, GNI per capita = $2930
What were 3 main impacts of the Haiti EQ?
- 230000 deaths
- 300000 injuries
- 1.5 million made homeless
- $10 billion of damage
- 2 million left without food or water
What were 3 main responses to the Haiti EQ?
- UK Gov donated £20 million
- bottles water and purification tablets supplied
- new homes built to higher standards
- USA sent 1000 troops
- 235000 people moved out of Port-au-Prince
When was the Uk heatwave?
Summer 2018
What caused the UK heatwave?
High air pressure and weak jet stream (unable to move high air pressure). Climate change and global warming - already increasing temperatures
What is the UK’s development like?
AC- well developed with good infrastructure.
What were 3 Key effects of the UK heatwave?
- stress on local councils
- boost in tourism
- water shortages
- suffering ecosystems
- wildfires
- mass littering
What are 3 key responses to the UK heatwave?
- hosepipe ban reduced water shortages by 5 to 10%
- NHS and public health England heatwave plan
- leveled warning system
What caused the 2010 Iceland Volcanic eruption?
1) constructive plate boundary
2) magma filled chamber, increasing pressure and causing magma to rise, filling fissures in surface
3) increased silica and gas caused magma in chamber to thicken, causing a second eruption
4) reaction of lava and ice caused a tephra cloud
What is Iceland’s development like?
AC - fourth most developed int he world
GNI per capita = over $70000
life expectancy = 83
literacy rate = 99%
What were 3 main impacts of the Iceland 2010 Volcanic eruption?
- all flights, worldwide, cancelled for 3 days after eruption
- $2 billion cost to airlines
- 04% drop in value of holiday companies
- roads destroyed
- health impacts, such as respiratory issues
- flash floods caused 20 farms to be destroyed
What were 3 main responses to the Iceland 2010 eruption?
- National emergency agency were rapid to respond - bridges repaired..
- countries grounding all aircrafts
- no deaths
- coordinated information given to public
What are jet streams
Strong bands of wind which are found just below the troposphere where circulation cells meet
Why is atmospheric circulation necessary?
there is an imbalance of solar energy on Earth’s surface (more at equator), atmospheric circulation redistributes this heat
