Paper 3 (2023) Flashcards
(29 cards)
Explain two factors that might influence rates of erosion along coastlines
Nature of the coastal geology, rock type and structure leading to areas that are more or less resistant to erosional and weathering processes
The morphology of the coastline
Different characteristics of the waves will have an influence such as wave type and energy
Varying strength of winds and fetch on wave characteristics
Marine processes related to wave action
Human activity including hard and soft engineering and coastal management
Threats to coral reefs
Warming sea surface temperatures
Acidification of the oceans
Rising sea level
Pollution from land
Physical damage
Overfishing and methods of fishing
Sedimentation from river input
Crown of Thornes starfish
Tourism and coastal developments
Management strategies to reduce threats to coral reefs
Reducing carbon emissions to slow climate change
Limiting harmful human activities
Designation of MPAs
Development of regulations for fishing such as quotas
Effective monitoring of reefs
Preventing harmful coastal development
Controlling pollution from the land and sea
Eradication of Crown of Thornes starfish
Sea level rise affecting depositional and erosional coastal landforms
A small rise in sea level on a rock coast will only affect the erosional landform slightly. Sea level rise may affect cliffs as the coastal area may no longer be protected by beaches and other features. Rising sea level on coasts where deposition is occurring will affect the movement of material and the associated landforms such as offshore bars and tombolos
Explain why volcanoes can have greater impacts than earthquakes
Earthquakes have a maximum magnitude which can limit their impacts
Volcanoes could involve a greater variety of hazardous events such as pyroclastic flows, lava flows, ash clouds and lahars
Volcanoes have the potential to have a global impact while earthquakes affect a more limited area
Earthquakes are short-lived whereas volcanic activity can continue for months
Many countries have a greater ability to prepare for earthquakes than volcanoes
Hazards of large-scale atmospheric disturbances
Storm surges, coastal flooding, intense rainfall and high winds. These give rise to secondary hazards including severe river floods and mass movements
Suggest two reasons why coastlines lose of gain land
Balance of erosional and depositional marine processes
Wave approach and energy leading to either erosion or deposition
Nature of the coastal areas with differing resistance to erosion
Human development affecting coastal processes
Hard and soft engineering to hold the line or managed retreat
Sea level change
Assess the extent to which the characteristics of coastal cliffs are the result of marine processes
Marine processes are largely erosional processes
Also controlled by other factors such as climate and wave energy
Sub aerial processes of weathering and mass movement will also be factors
Exposure to waves and storms is important
Geology and rock type
Human impact such as engineering to protect cliffs
To what extent is hard engineering more successful than soft engineering in coastal management?
How permanent such as need for replacement
Reducing coastal erosion
Increasing coastal deposition where needed
Increasing stability of cliffs
Protecting vulnerable infrastructure
Enhancing tourism
Cost-benefit analysis
Stakeholder satisfaction
Protection or creation of wildlife habitats
Suggest reasons for the difference in duration of precursors for natural hazards
Earthquakes are the sudden release of stress and there is little to no indication of potential movement prior
Hurricanes take time to develop in open oceans and can be identified by satellite imagery and other sensors
Tsunamis occur quickly after the trigger but timing depend son distance of travel and strength of earthquakes
Volcanoes usually have a build-up of magma pressure before the main eruption. Also varies with the type of volcano. Shield volcanoes show signs well in advance of eruption
Prediction methods for mass movements
Based on assessment of the environment at risk and is mainly hazard mapping and monitoring. Requires an understanding of the causes of mass movements including rock types, slope angles, trigger events and potential earthquakes. Some mass movements such as mudflows which follow a similar path each time might be easier to predict. Old landslides may be reactivated which aids prediction
Preparation for mass movements
Includes prevention measures. By understanding the location and causes it may be possible to prepare
Putting in retaining structures, bolting, pining, netting, shotcrete for rockfalls
Draining (mudflows) and regrading slopes for landslides
Snow avalanche fences and deflectors triggering unstable snow slopes
Building regulations and similar procedures
Assess the extent to which it is possible to prepare for the impacts of earthquakes
Earthquakes are difficult to predict but prone areas are easier. Prediction may provide enough time for impacts to be lessened. Areas subject to earthquakes can adopt measures to minimise impacts such as structural engineering, earthquake drills and education. Once an event occurs efficient resource allocation will reduce impacts on people. Secondary impacts can be prepared for
Explain why the rates of erosion and deposition vary along a stretch of coastline
Wave energy and wave type. High energy waves lead to erosion and low energy waves to deposition
Wind speed and direction influence wave energy
Tidal currents
Resistance of coastal geology to processes of erosion and its ability to yield sediment through weathering and mass movement
Sediment input from rivers
Installation of sea walls limit erosion while groynes increase deposition
Vegetation such as mangroves
Assess the influence of sub-aerial processes in the formation of coastal landforms
Includes weathering and mass movement. Other processes such as erosion and deposition may be more importance. Sub aerial processes contribute to landform formation by weakening coastal rocks enabling them to be eroded more easily. They also modify coastal landforms after their formation. May have less effect on the formation of depositional landforms but can contribute to sediment supply
Evaluate the view that sea level rise is the greatest threat to coral reefs
Creates deeper water over the coral so they receive less sunlight and insolation. Many reefs can grow at a rate that equals the rate of sea level change and so the water depth does not increase. Greater threats may come from increased acidity, sea surface temperature rise, pollution from agricultural and industrial sources, physical damage from increased storminess and damage from human activities
Explain the factors which influence the hazard of soil liquefaction
Largely related to the geological characteristics of the landscape. Most likely to occur in areas of loose, unconsolidated materials found in coastal areas of marine deposits and river valleys with fluvial deposits. May also occur in areas of glacial and aeolian deposits such as former lake beds. Occurs when sediments are shaken such as by an earthquake. Location of epicentre and magnitude of event are also important
Monitoring to manage mass movements
Purpose is to aid prediction and preparation. It can involve monitoring water content, slope angle, strain and visual signs of movement such as tree bending and wall bulging
Methods of managing mass movements
Land use zoning
Education and evacuation drills
Drainage of slopes
Afforestation
Hard engineering
Hazard mapping
To what extent are high winds the most significant hazard of small scale atmospheric disturbances?
High winds can cause primary and secondary damage to lives and property. Can remove or damage obstacles. Rotational movement can twist objects from their fixings and strong uplift can carry objects up to heights from which they then fall. Other hazards include intense precipitation which can cause localised flooding, mass movement and pressure imbalances which cause building walls and roofs to explode outwards
Explain the changes in waves as they move towards the shore
Enter shallower water which subjects the orbiting molecules at the waves base to friction and their speed of movement is slowed. This causes waves to bunch up and reduces their wavelength. The faster moving water near the sea surface piles up, increasing wave height. Eventually the crust of the advancing wave starts to spill over the lower part and eventually the wave breaks.
Assess the role of sea level change in the formation of coastal landforms
Sea level change includes rise and fall, isostatic and eustatic and historic and recent
Landforms influenced by sea level change include raised beaches, relic cliffs, rias, fjords, Dalmatian coasts, tombolos and barrier beaches
It has little or no influence on the formation of others
Threats to coral reefs
Global warming
Sea level rise
Acidification
Crown of Thornes starfish
Pollution
Physical damage
Management of coral reefs strategies
Global reduction in greenhouse gas emissions
Limiting human activities such as fishing and blasting
Protection
More sustainable tourism
International cooperation and funding of initiatives
Education
Monitoring and enforcement
