Geography Exams Semester 1 Flashcards
Geomorphic hazards:
Hazards concerned with the movement of the earths surface, these can include landslides, earthquakes, tsunamis, volcanoes etc
Earthquakes:
They are associated with tectonic plate boundaries, they also occur where fault lines lie. At the heart of an earthquake is an epicentre from which seismic waves radiate.
What is a seismic wave?
The source of energy required for the earths movement.
Tsunami:
A series of waves usually triggered by an earthquake, volcanic eruption or another cause eg meteorite that causes a rapid displacement of water body.
Volcanoes:
A vent on the earths surface that allows magma to escape the interior, explosiveness is determined by how easily the magma can escape and the gas trapped within it.
What are the 3 types of volcanoes?
- Shield volcanoes: the magma is very hot and runny, eruptions are gentle
- composite volcanoes (strato): the magma is cooler and sticky, explosive eruption
- caldera volcano: no build up of materials, vent unsupported and collapses.
Landslides:
Movement of mass rock, soils and debris down a slope
Lithosphere:
Includes the crust and upper mantle (800km thick)
Continental crust:
25-100 km thick, made up of granite rocks
Oceanic crust:
11-16 km thick, dense basalt rocks
Core:
Outer core: 2900km thick, liquid
Inner core: 5100km thick, solid
Tectonic plate theory:
- Suggests that tectonic forces are produced by slow movement of 12 large tectonic plates of rock within the lithosphere (2-5cm per year)
- rock in mantle moves slowly in series of giant convection currents produced from the core
- currents rise and spread beneath the crust before cooling and sinking.
How do plates move?
Force created by friction isn’t enough to move plates.
Slab pull- the weight of the leading edge of a plate that is being subducted into the mantle due to a collision.
How does the sea floor spread?
- The earths magnetic field reverses polarity from time to time (paleomagnetism- a record of these changes) is preserved in the basalt rock, when material rises through the mid-oceans ridges and cools.
- symmetrical pattern of paleomagnetic stripes in rocks on either sides of the ridges and rocks at a similar distance away from the ridge lines were found to be the same age
Convection currents in the mantle:
Mechanism of how tectonic plates move
Convection currents in the mantle are the force moving tectonic plates and making new hotspots
Divergence:
As plates seperate, magma is forced into the gap creating an oceanic ridge. Earthquakes can occur
Convergent:
Plates move towards each other, forces of compression
When an oceanic plate meets continental plate, the oceanic subducts into the mantle forming an ocean trench in subduction zone.
When two continental plates collide, the surface is force upwards forming mountain ranges
Transform plate boundaries:
Movement of plates past each other, creates tension
Results in horizontal displacement of the surface along the fault line
These result in earthquakes as the built up pressure along the fault lines is released.
Spatial distribution:
Refers to how features or objects are arranged on the earths surface.
How to measure earthquakes?
The Richter scale (not so much anymore)
- How intense was the earthquake (amount of movement and sheer energy released) determined on the moment magnitude scale
- What effects did the earthquake have? (Looks at damage caused) mercalli scale.
Moment magnitude scale:
Measures the amount of energy released. Calculated using a formula that includes the rigidity of the rock affected, the distance moved and fhe size of the area involved
Each magnitude releases approx 32 times more energy than the magnitude before it.
What is temporal distribution?
Concerned with examining the distribution of natural hazards over time
What are the 5 key points of the severity of a hazard?
Magnitude Duration Frequency Probability Scale of special impact
Three basic patterns in examining spatial distribution?
Clustered
Random
Uniform
What is the concept of risk?
Exposure or probability of a hazard event causing harmful consequences to people, property and the environment
6 reasons why people put themselves at risk:
Unpredictability Lack of alternatives Dynamic hazards Cost vs benefits Fatalism Adaptation
What is vulnerability ?
Assesses the level of risk and refers to the way a hazard event will affect human life and property.
What influences vulnerability?
Wealth and level of affluence
Educational awareness of what protection is needed
Levels of organisation
Technical ability to design/construct preventative infrastructure
What is a hazard?
A potential source of harm to a person, community or infrastructure
Natural phenomenon:
Physical event that doesn’t affect human beings
What is risk / hazard management?
Dealing with the short and long term consequences of a hazard and identifying methods to minimise those risks.
3 phases of risk/hazard management:
Predisaster- mitigation, preparedness, prevention
During the disaster- response
Post disaster- recovery, relief, rescue and rehabilitation
What is mitigation?
The ability to moderate the severity of a hazard
3 aspects of mitigation?
- the geographic extent of the hazard
- the spatial variations of the intensity of the hazard
- probability of occurance
What is preparedness?
Focus on guaranteeing that emergency services and people at risk are aware on how to respond during a hazard event
What can be done to deal with a hazard event? (6)
- logistical readiness
- response mechanisms and procedures
- rehearsals and training
- public education
- ensuring reserves of food, water, medicine etc
- development of emergency plans and evacuation plans
What is response?
Directed to the immediate needs of the population affected by the hazard event
List examples of responses to a hazard event:
- fire fighters
- evacuation
- emergency medical response
- decontamination
- transport
What is sustainability?
Meeting the needs of current and future generations through simultaneous environmental, social and economic adaptation and improvement
Stakeholders:
A person/group of people who have a vested interest
4 types of Ebola virus :
Sudan Ebola virus
Tai forest Ebola virus
Bundibugyo Ebola virus
Zaire Ebola virus
Factors effecting morbidity and mortality of Ebola:
1- type of virus
2-outbreak geography (sub factors affecting the spread, ie transport)
3-route of infection (ie through needles 100% mortality)
4-clinical symptoms (ie neurological and haematological symptoms = higher mortality)
5-effectiveness of interventions
What effect did Ebola have on infrastructure, economy and jobs?
- many projects put on ‘hold’ as all funds directed to treatments
- GDP fell, productivity was severely affected ie agricultural markets in Sierra Leone (coffee, cocoa and rice)
- employment lost due to 1. The persons died, 2. The person had to care for a sick relative
3. Fear of catching disease through workplace
Ebola impacts of physical and mental health:
- survivors isolated by communities, people believe they’re still infected
- survivors murdered by communities, as well as health workers being killed
- virus remains in parts of the body ie eyes and semen
Cultural practices that affected Ebola:
- consumption of bushmeat
- burial practices (kissing and touching the dead body)
- traditional medicine (locals preferred traditional healers)
- fear and obstruction of health interventions (cultural fear of western medicines)
Globalisation :
Includes international integration and interactions between people and places, companies, governments etc.
Driven by international trade/investment and aided by information technology
Accessibility:
An evaluation of how difficult it is to move something from one place to another
What is the shrinking world?
Refers to how the world has developed overtime, aided by advances in technology and globalisation, doesn’t directly mean the world is shrinking
What is friction of distance?
Distance usually requires some amount of effort, energy,time and or other resources to overcome. Due to the ‘friction’, spatial interactions will tend to take place more often over shorter distances; amount and intensity of interaction will decay with distance.
What is time space convergence ?
The lessening of the distance between two point.
The process by which places can be said to become closer to eachother as the time taken to travel between them decreases
What is spatial reorganisation?
A process whereby the geographies of production and consumption are transformed
What is centralisation?
The concentration of an activity in fewer locations, and often in larger settlements
What is specialisation?
The concentration of specific activities in these areas which possess the greatest comparative advantage for them
What is comparative advantage?
The ability of an individual, group or country to carry out a particular economic activity (such as making a specific product) more efficiently than other activity.
What is spatial interaction?
The effects of movement or flows of air, water, material, life forms, people, goods or information between different locations on earth
What are transnational corporations?
Companies that have operations in two or more countries.
- growth of TNCs started in 19th century due to development of factories, better storage and efficient transport
- 7,000 TNCs (1970) to 38,000+ TNCs today
What are the 5 stages of development ?
- Traditional society
- Pre conditions for take off
- Take off
- Drive to maturity
- High mass consumption
What is the Brandt line?
Imaginary division which divides the countries into the rich north and the poor south
What is the demographic transition model?
A sequence of changes over a period of time in the relationship between birth and death rates as well as overall population change.
What are the 5 stages of the DTM?
Stage 1- (high fluctuating) High birth and death rates
Stage 2- (early expanding) birth rates high, death rates fall
Stage 3- (late expanding) birth rates fall, death rates fall
Stage 4- (low fluctuating) low birth and low death rates
Stage 5- (decline) death rate slightly exceeds birth rate, population declines
