Paper 1 Section A Flashcards
What are natural hazards
Natural hazards are sudden, severe events which make the natural environment difficult to manage.
What 4 factors affect risk
Urbanisation,poverty,farming and climate change
What are the 2 types of crust and their characteristics
Oceanic-Dense and thin
Continental-Less dense and thicker
Describe the movements of plates at plate margins
Constructive-Plates separate forming new crust, causing volcanic eruptions
Destructive-Plates collide causing subduction, earthquakes, volcanic eruptions and fold mountains
Conservative-Plates slide by each other causing earthquakes
Hot spots is where….
some volcanoes occur due to the crust being thin allowing magma to break through the surface
Cause of the Chile earthquake
Subduction of one plate beneath another just off the coast of central Chile
Cause of Nepal earthquake
Plates colliding
Magnitude of Chile earthquake
8.8 shallow focus
Magnitude of Nepal earthquake
7.9 very shallow focus
Chile primary effects
.500 killed
.12,000 injured
.800,000 people affected
.$30bn damage
Nepal primary effects
.9,000 killed
.20,000 injured
.8m affected
.$5bn damage
Chile secondary effects
.Communities cut off by landslides
.Chemical plant fire near Santiago forced evacuations
Nepal secondary effects
.Communities cut off by landslides and avalanches
.Avalanches on Mount Everest killed 19 people
Chile immediate responses
.Key roads repaired within 24hrs
.Most power and water restored within 10 days
.$60m national appeal built 30,000 emergency wooden shelters
Nepal immediate responses
.Overseas aid included widely active NGOs-Oxfam
.300,000 people migrated from Kathmandu for shelter and support
Chile long-term responses
.Government reconstruction plan to help 200,000 households
.Full recovery within 4yrs likely
Nepal long-term responses
.International conference to seek technical and financial support
.Indian blockade in 2015 caused crippling fuel, medicine and construction material shortage
Why do people live at risk from tectonic hazards
.No experience or knowledge of the risks
.Volcanoes bring fertile soils, rich mineral deposits and geothermal energy
.Effective monitoring of hazards allow evacuation warnings to be given
How can risks from hazards be reduced
.Monitoring-Remote sensing(V) and microquakes(E)
.Prediction-Monitoring of volcanoes allows accurate prediction,accurate predictions for earthquakes are impossible due to a lack of clear warning signs but historical records can help determine possibility
.Protection-Earth embankments and explosives used to divert lava, drills for earthquakes helps keep people alert and prepared as well as strong infrastructure
.Planning-Risk assessment(V+E)
What do sinking and rising air create
.Sinking air-High pressure
.Rising air-Low pressure
Describe the movement of surface winds and what it creates
Surface winds move from high to low pressure, transferring heat and moisture from one area to another
What does the tilt and rotation of the earth cause
.Surface winds to curve and change seasonally
.Causes relative changes in the position of the overhead sun
Why is it cloudy and wet in the UK
Because 60 degrees north is close to where cold polar air from the north meets with the warm subtropical air from the south.Surface winds bring warm and wet weather as rising air cools and condenses forming clouds and rain.
Why is it hot and dry at deserts
Because most deserts are found at about 30 degrees north and south where sinking air means high pressure, little rain, hot daytime temperatures and cold nights
Why is it hot and sweaty at the equator
Because low pressure marks where the sun is directly overhead, hot humid air rise cools and condenses causing heavy rain hence the tropical rainforests
What is the lithosphere
The solid outer part of earth includes the brittle upper portion of the mantle and crust
What is the asthenosphere
The mechanically weak and ductile region of the upper mantle of earth
What is the quaternary period
The period of time that stretches from 250m years ago to the present day.
What is climate change
Refers to long-term shifts in temperature and weather patterns-Side effects of global warming
What is global warming
Refers only to the earths rising surface temperature
What is a rift valley
A long narrow valley lying between two normal geologic faults. Usually form where the earths lithosphere has become thin through extension associated with plate tectonic processes
What are some of the required conditions for tropical storms to form
.Water temperature has to be 27 degrees or above
.Cluster of thunderstorms
.Coriolis effect
Light wind sheer
.40-60m depth
How do tropical storms form
. Warm ocean water causes air to rise, drawing up water vapor that forms towering thunderstorm clouds.
. Condensation of water vapor releases heat, powering the storm and drawing up more moisture.
. Multiple thunderstorms combine to form a giant rotating storm.
. The Coriolis effect spins the storm, creating winds over 120 km/h and a large cloud spiral with a calm central eye.
. Prevailing winds move the storm across the ocean, strengthening as it picks up more heat energy.
. On reaching land, the storm loses its energy supply (evaporated water) and weakens.
Typhoon Haiyan primary effects
.6,300 killed
.Over 600,000 displaced
.40,000 homes destroyed or damaged
.Over 400mm of rain caused widespread flooding
Typhoon Haiyan secondary effects
.14m affected-6m jobs lost
.Infrastructure including schools destroyed
.Flooding caused landslides blocking roads and restricting aid
Typhoon Haiyan immediate responses
.Over 1,200 evacuation centres set up
.Rapid overseas aid-NGOs
.Field hospitals for injured
Typhoon Haiyan long-term responses
.More cyclone shelters built
.Rebuilding of infrastructure
.Homes rebuilt in safer areas
Extreme weather faced by the UK
.Thunderstorms
.Prolonged rainfall
.Drought and extreme heat
.Heavy snow and extreme cold
.Strong winds
Somerset levels causes
.Rivers had not been dredged in 20yrs
.High tides and storm surges
.Depressions brought by a record rainfall
Somerset social, economic and environmental impacts
.Over 600 houses flooded and 16 farms evacuated
.Villages cut off
.£10m damage
.14,000 ha of farmland flooded
.Massive debris clearance required
Somerset immediate responses
.Cut off villagers used boats for transport
.Huge media interest
.Community groups and volunteers supported
Somerset long-term responses
.£20m Flood Action Plan
.8km of rivers Tone and Parrett dredged
.Possible tidal barrage at Bridgwater by 2024
Evidence for climate change
.Shrinking glaciers and melting ice
.Rising sea levels-Thermal expansion,low lying islands such as the Maldives in danger of flooding
.Seasonal changes-Tree flowering and bird migration advances
What are the 3 main natural causes of climate change
.MILANKOVITCH CYCLE:
-Eccentricity=every 100,000yrs the orbit changes from almost circular to mildly elliptical and back again
-Axial tilt=Every 41,000yrs the tilt of the earths axis moves back and forth between 21.5 and 24.5 degrees
-Precession=Over a period of around 26,000 years the axis wobbles from one extreme to the other
.SOLAR ACTIVITY-surface of the sun has dark patches called sunspots which mark short term regions of reduced surface temperature, usually accompanied by explosive, high energy solar flares increasing heat output.Over a period of 11yrs sunspots increase from a minimum to a maximum and back again,
.Volcanic activity-Volcanic ash blocks the sun, sulphur dioxide is also emitted acting like mirrors to reflect solar radiation back into space, over many years this reduces temperature.
What is the greenhouse effect
.A natural process where greenhouse gases (CO2, water vapor, methane) trap heat in the Earth’s atmosphere.
.Keeps Earth’s temperature suitable for life.
.Sun’s energy reaches Earth, some is absorbed, and the rest is emitted as heat, which is trapped by greenhouse gases.
What is the enhanced greenhouse effect?
.Caused by human activities (e.g., burning fossil fuels, deforestation).
.More greenhouse gases (CO2, methane) are released, intensifying the natural greenhouse effect.
.Leads to global warming and climate change.
Managing the impacts of climate change methods
.Carbon capture
.Afforestation-Timber Act of 2014-requires a licence to harvest and trade timber
.International agreements-Paris agreements 2015 aimed to limit global temperature increases to 1.5 degrees above pre-industrial levels
.Agricultural adaptation-Crop rotation, drought resistant crops and plant trees for shade
