AS Mass movement: Carson and Kirkby’s classifications of mass movements

Although this is not directly needed, this diagram may appear in an insert and you may be required to interpret it in an exam.

AS: Droughts

•        The hydrological cycle accounts for 1% of the total water on the planet
•        The hydrological cycle is a closed system because water is neither added nor lost
•        Over the last 300 years the world’s population has increased x7 and demand for water has increased x40.
•        Severe water stress is experienced by 1.1 billion people in 80 countries

Reliability of rainfall

•        Few homes in LEDC’s have piped water
•        Few developing countries have the money or the technology to build dams to store water. If they have it was mostly like built with foreign aid
•        Torrential downpours give insufficient time to infiltrate the ground. Instead surface runoff create flash floods
•        The most vulnerable areas are desert margins and tropical interiors where average annual rainfall is low and rainy seasons are short
•        Many countries just experience wet/ dry seasons. If rain fails one year, the result of produce can be disastrous

Clean Water

•        1.1 billion people lack clean water
•        Rural areas use local rivers for drinking as well as washing and sewerage disposal
•        Shanty towns lack proper drainage for sewerage which may pollute water ways
•        Disease can break out
•        Villagers can help themselves out though by: building wells to reach a permanent supply, lining wells with concrete, using pumps and teaching about proper hygiene

AS: Atmosphere & Weather - Global Warming case study

Global warming

·      The concern about global warming is the build-up of gases within the atmosphere.

·      Deforestation has meant that the extra CO₂ that has been produced, can not be absorbed by trees and converted in oxygen.

·      An increase in greenhouse gases has meant that there is an increase in long-wave radiation being absorbed by these gases. This has meant the earth has gotten warmer.

Impacts of Global warming

·      Climatic

o   Increased storm activity

§  Tornadoes in the mid west

§  Hurricanes

§  Typhoons

§  Cyclones

o   Temperature increases

§  With no action, temperatures will increase by 2.5⁰C in the next 50 years.

o   Reduced rainfall

§  Leads to droughts

o   Rise in sea temperatures

·      Other

o   Forest fires

§  Increase of fires because of dry forests

o   Coral bleaching

§  From a rise in sea temperatures

§  For example reefs on the Great Barrier Reef

o   Water shortages

§  4 billion could face water shortages if temperatures increase 2⁰C.

o   Changes in agriculture

§  Samoln fishing could become obselte

§  A 35% decrease in yields if temperatures increase 3⁰C

§  However there could be an increase in timber yields

§  Increase in growing seasons in temperate and alpine areas

o   Flooding

§  By 2100 an overall 1m rise in sea levels if no action has occurred.

§  Flooding will occur in Delta areas more frequently e.g. New Orleans.

§  4 million km² is threatened

§  200 million could be at risk of loosing their homes from floods by 2050.

o   Changes to Tourism

§  Longer tourist seasons for summer tourist destinations

§  Winter tourism to ski fields and glaciers may decline.

o   Soil erosion

§  Especially in areas such as the amazon that is damaged by slash and burn practices

o   Spreading of disease

§  A 2⁰C rise could increase the number infected by Malaria by 60 million

o   Extinction of wildlife

§  If temperatures increase by 2⁰C, 40 % of species will become extinct

§  Habitats could decrease in range e.g. Polar Bears

§  Range of Species could increase e.g. Butterflies in the UK

AS: Mass Movement

Slope Processes and development

Mass movement

Is the movement of weathered material down a slope under gravity.

The slope is a system with inputs, outputs and flows.  It has exogenetic factors (external factors) and endogenetic factors (internal factors).

The slope as an open system

Humid climate slopes: Convex and concave slope segments (convex, concave, convex, concave formation).

Arid climates slopes:  Resistant jointed vertical rock slope, then a gentler slope with regolith in a concave shape with boulders, mostly rock fall occurs.

Slopes near fault lines: Fault block

AS: A Case study on mass movement MEDC vs. LEDC contrast

Example of a (accelerated by man) Landslide in a MEDC:  Abbotsford Landslide, Dunedin, NZ 1979

Cause:

•              1978 families noticed cracks appearing in their homes.

•              1979 workmen discovered that a leaking water main had been pulled apart. Geologists discovered that water had made layers of clay on the hill soft, and the sandstone above it was sliding on this slippery surface.

•              Construction of the nearby Dunedin southern motorway, an earthquake that occurred in the area in 1974, deforestation (reduced evapotranspiration), increased urbanization (involved cutting into slope and infilling) and quarrying activity on the toe of the slope in the decades before may have further affected the land’s stability.

The landslide:

•              On July 27^th the slide began to accelerate.

•              Early warning system was put in place by Civil defense and a civil emergency was declared on the 6^th of August 1979. This was not thought to have been necessary, as geologists believed the slope would only move slowly.

•              However on the 9^th of August a 7 ha section of East Abbotsford started moving down the slope at a rate of 3m per minute, taking houses with 17 people inside.

•              It was essentially a block of sandstone resting on a bed of weaker clay. Displacement of 50m took place in about 30 minutes, leaving a small rift 30m deep in the head of the slope. In addition the slope was on an angle of 7⁰. Water collected in the impermeable clay, reduced its strength and cohesion, and caused the sandstone to slip along the boundary of the two rocks.

•              The sandstone involved 5.4 million m³ of material. At first the land moved as slow as soil creep, followed by a rapid movement with speeds of 1.7 m per minute.

Impacts:

•              Nobody was killed but 69 homes were destroyed or damaged and 200 people were displaced. The total cost from the destruction of the homes, infrastructure and relief organization amounted to £7 million ($10-13 million NZ today). In total 18 ha was affected.

•              Insurance schemes and government relief to cope with such disasters meant that residents were compensated for any damage.

•              However other impacts such as depressed housing prices, trauma and the cost of a prolonged inquiry were not immediately appreciated.

•              Lessons on landslide preparedness, and the affect human activity has on slopes can be learnt from this.

Case Study on a Physical Landslide in a LEDC: Vargas State, Venezuela  - 1999

Causes:

•              First two weeks of December 1999 saw an unusually high amount of precipitation (40-50% above normal rainfalls).

•              Political corruption – allowing shanty-towns to be built on steep slopes surrounding Caracas. The slopes around the region were changed to accommodate vast squatter settlements.

Landslide:

•              15-16^th December the slopes of the 2000m Mt Avila began to pour forth rock and mud burying 300 km stretch of the central coast.

•              Rains triggered mudslides, landslides and flash floods in between the mountains and the Caribbean Sea.

•              Search and rescue were deployed to search for survivors but very few were found in the first few days.

Impacts:

•              Rains triggered mudslides, landslides and flash floods which claimed the lives of 10,000 -50,000 (unknown accurately as most people were buried under mud or swept to sea) in between the mountains and the Caribbean Sea.

•              150,000 were left homeless by landslides and floods in the states of Vargas and Miranda.

•              Slum dwellings were often buried by mudslides (8-10m deep) or swept out to sea. This is why fatalities are unknown as many went missing and entire families went unreported as missing.

•              Bridges, roads, factories, crops, telecommunications and the tourism industry (in the immediate future) were destroyed. The international airport in Caracas was closed.

•              Containers at the seaport of Maiqueita were damaged. Harzardous material leaked out of these containers. Operations at the port were halted and hampered efforts to bring in emergency supplies. The economic damage was estimated at $3billion.

•              70% of Venezuelan population was living in this small coastal area. The government then made a plan to move some of the population to inland areas.

•              As a result of these landslides a plan to rebuild 40,000 homes was created for Vargas. A $100 million extension was planned for the international airport. The country’s main seaport in Vargas, was also planned to be modernized. Tourist destinations in Macuto and Camuri Chico were also rebuilt. Towns such as Carmen de Uria were not rebuilt, and instead created into parks & bathing resorts.

•              These improvements reduced the number of fatalities to 14 in the next 2005 mudslides in the region.

IGCSE: Case Studies: Trans National Corporations – Wal-mart

•        Wal-mart was first opened in 1962 in Arkansas in the USA
•        Stores opened around across the USA soon after and also opened stores in China, Japan, Canada, Brazil, Argentina, Mexico, India and in the UK (where it’s called ASDA).
•        It owns over 8000 stores and employs over 2 million people

Positive effects:

•        Wal-Mart creates lots of jobs for example, in Argentina three new shops opened in 2008 creating 450 more jobs.
•        Wal-Mart invests money in sustainable development for example; in Puerto Rico 23 stores have solar panels fitted onto their roofs to generate electricity.
•        Wal-Mart donates hundreds of millions of dollars to improve health in countries it is based in. E.g. In 2008 in Argentina the company donated $77,000 to local projects and gave food to help feed 12000 people.
•        Wal-Mart offers more skilled jobs to local people in LEDC’s
•        Local Companies and farmers supply to Wal-Mart, which in Canada created about $11 billion of business per year.

Negative effects:

•        Wal-Mart can cause smaller shops in the area to go out of business
•        Not all Wal-Mart workers are payed the same wages e.g. in the USA workers earn about $6 but in China they earn $1 per hour
•        Some companies that supply Wal-Mart work long hours e.g. In Bangladesh the max a worker can work is 60 hours per week, but the company that supplies Wal-Mart with Clothing work workers around 80 hours per week.
•        These stores take up lot’s of land that would have been used for farming e.g. A Wal-Mart in Hawaii is roughly 21000m².