Volcanoes, Earthquakes & Fold Mountains

When plates separate a volcanic eruption occurs.
When plates collide it forms an earthquake.
Fold mountains are formed where plates collide.
Earthquakes take place most commonly where plates collide or slip past each other.

Some effects of earthquakes:

• Buildings close to the epicentre sway and collapse.

• Roads crack and railway lines bend.

• Gas pipes break, causing fires

• Huge tidal waves called tsunamis can result from earthquakes beneath the sea bed.

Iceland is known as the land of ice and fire because it has lots of active volcanoes. Iceland is on the middle of a fault line.

• The crust of the earth is divided into plates. Convection currents in the mantle below cause the plates to move slowly, carrying continents with them. this process is called continental drift. It causes the boundaries of plates to collide with and separate from each other.

• Folding can occur where plate boundaries collide. Compression causes parts of the crust to become raised and buckled into mountains. The rocky mountains, the Andes, and the mountains of Munster are all examples of fold mountains.

• Earthquakes can occur where plates collide or slip and past each other .The compression and cracking of rocks causes shock waves to spread from the focus of an earthquake. When these waves reach the surface, the ground trembles which causes great damage to life and property.

• Mid ocean ridges may be formed where plate boundaries separate beneath the oceans. Magma makes its way to the surface along long cracks to form long ridges, such as the mid Atlantic ridge.

• Volcanic mountains are also formed where plates collide. Magma reaches the surface rapidly through a vent. layers of ash and lave gradually form a volcanic cone.

The world's largest earthquake and volcanic zone lies around the rim of the pacific ocean. It is called the pacific ring of fire.

Rocks & Natural Resources

• igneous rocks are formed when molten volcanic materials cools down.

• Granite, which contains crystals, is formed slowly beneath the surface of the earth.

• Basalt contains no crystals and is formed rapidly on the earth's surface.

• Sedimentary rocks are formed from the compressed remains of animals, plants or other rocks.

• Sandstone is formed from compressed grains of sand

• Limestone – Ireland's most common rock – is formed from the compressed remains of the sea creatures. This permeable, stratified rock is weathered by rain and may contain fossils.

• Metamorphic rocks are formed when other rocks change as a result of great heat or pressure.

• Limestone changes to marble.

• Sandstone changes to quartzite.

Rocks provide us with natural resources. fossil fuels may be extracted by mining (for coal) or drilling (for oils and gas). Rocks used for building materials are usually quarried.

Weathering & Erosion

Erosion

Erosion is the breaking down and movement of rock by water, ice and air.

Weathering

Weathering is the simple breaking down of rocks.

Mechanical weathering

Breaking up of rocks into smaller pieces.

Can be caused by:

• Frost (Freeze-thaw action)

• Sudden temperature changes

• Plants and animals

Chemical weathering

Causes rocks to dissolve or decompose.

Can be caused by:

• Rain

- The Burren in Co. Clare is a karst area of exposed limestone

• Carbonic acid in rainwater passes through and reacts with the calcium carbonate in the permeable limestone. This results in the chemical weathering of limestone.

• The karst surface contains some swallow holes and bare limestone pavements with clints and grikes.

• Beneath the surface are passages and caverns, with stalactites on their ceilings and stalagmites on their floors. Where stalagmites and stalactites meet, pillars exist.

Denudation: Wearing away of rocks.

Mass Movement

• Mass movement is the down slope movement of regolith under the influence of gravity.

• Soil creep is the slowest form of mass movement. It may cause tree trunks, poles and fences to lean over. It may also cause walls to break and terracettes to form.

• Bog bursts happen on a peaty slopes after heavy rain. Saturated peat runs rapidly down slope.

• Mud flows are similar to bog bursts. Inhabitants in the village of Panabaj in Guatemala were killed when heavy rains and the removal of trees resulted in a disastrous mud flow.

• Landslides are the extremely rapid movement of rock or earth down very steep slopes. They may occur  where the sea undercuts sea cliffs or where road-builders make steep-sided cuttings in hillsides.

Rivers

At their youthful stages, rivers usually erode downwards. The main processes of erosion are as follows:

• Hydraulic action - the force of moving water

• Abrasion - erosion by the river load.

• Attrition - erosion of the river load

• Solution - chemical erosion

Landscape features formed by young rivers include:

• V-shaped valleys

• Interlocking spurs

• Waterfalls
  

rivers transport their load in three ways. Very light particles are suspended, heavier particles are bounced and still heavier pebbles are dragged along the shore.

Landscape features formed by mature rivers include:

• valley troughs with wide floors and gentle sides

• broad meanders

At their old stages, slow-flowing rivers deposit much of their loads. Landscape features of old rivers include:

• flat, low-lying flood plains

• horseshoe-shaped ox-bow lakes

• levees at the side of rivers

• deltas at the mouths of some rivers
  

human activities can prevent or cause flooding. The poor maintenance of levees and the drainage of wetlands contributed to disastrous floods in new Orleans, USA, following hurricane Katrina in 2005.

people sometimes change river processes by building dams. Dams provide hydroelectric power. They also create artificial lakes which can be used for water storage and for water sports. But the dammed lakes flood farmland. The building of dams is costly and may disrupt wildlife.

Glaciation

Glaciers are slow-moving rivers of ice. They erode highland areas by plucking (pulling rocks from the ground) and by abrading (scraping the surface over which they pass). Features of erosion include the following:

• Cirques, which are basin-shaped hollows where glaciers began.

• Arêtes, which are knife-edged ridges between cirques.

• Glaciated valleys, which have steep sides and flat floors.

• Ribbon lakes on the floors of glaciated valleys.

• Hanging valleys up on the sides of the glaciated valleys.

• Fords, which are drowned glaciated valleys.
  

Moving ice transports material from highland to lowlands. Some materials are transported on the surfaces of glaciers in the form of moraines. Features of deposition are found mainly on lowlands and include the following:

• Lateral, medial and frontal moraines on the floors of glaciated valleys.

• Drumlins, which are oval-shaped hills of boulder clay.

• Erratics, which are boulders carried from distant places.

• Outwash plains of sand and gravel laid down by meltwater from the ice.

• Eskers, which are long, winding ridges laid down by rivers coming out of ice fronts.
  

The Sea

The sea erodes by means of:

• Hydraulic action (erosion by water)

• Compressed air in the rocks.

• Abrasion (erosion by the sea's load)

• Attrition(erosion of the sea's load)
  

Features of erosion include the following:

• headlands and bays

• sea cliffs

• sea caves

• sea arches

• sea stacks

• blow holes
  

The sea transports its load:

• up and down

• along the shore by longshore drift
  

the sea deposits its load when its force is reduced.
features of deposition include the following:

• beaches

• spits

• bars

• lagoons

• tombolos
  

Sea walls, gabians and large boulders can be used to reduce sea erosion. Groynes are used to reduce longshore drift

Climates & Weather

the atmosphere or air that surrounds our planet is heated by energy from the sun. Solar energy heats the earths surface. Then long-wave energy passes from the earth back into the atmosphere, where some of it is trapped. This process is called the greenhouse effect and it provides enough heat for plants and animals to thrive on our planet.

Human activities increase the greenhouse gases. This results in global warming and climate change which could cause renewable energy sources to combat climate change.

Places near the equator receive sun rays from almost directly overhead. These rays are more concentrated and travel through a lesser depth of atmosphere than sun rays at places near the poles. This is why places in low latitudes are warmer than places in high latitudes.

• Air has weight and exerts pressure. Light, warm air tends to rise and exerts low pressure. Heavy, cold air presses down and exerts high pressure. Air moves from areas of high pressure to areas of low pressure. That is how winds occur.

• Throughout the world, there are general, prevailing patterns of moving air. These are called global winds and they are set up by the unequal heating of the earth at different latitudes. The directions in which global winds blow are also determined by Coriolis force, which is the effect of the rotation of the earth on its axis.

Ocean currents are also caused by unequal heating at different latitudes. Unequal heating sets up convection currents between warm and cool parts of the oceans. The global winds (which are themselves caused by unequal heating) help to drag the ocean currents along in their direction.

Ascending air (in depressions) and descending air (in anticyclones) give very different weather conditions.
Ascending air gives:

• low pressure

• strong winds

• much cloud

• precipitation

• unsettled weather
  

Descending air gives:

• high pressure

• calm

• clear skies

• dry weather

• settled weather

Depressions are born at the polar front where warm tropical air meets cold polar air. They move eastwards over the Atlantic and affect Ireland's climate , especially in winter.

• As a depression approaches, pressure falls, stratus clouds fill the sky and rain becomes continuous.

• When the warm front passes over, temperatures rise, the sky remains overcast and drizzle may fall.

• When the cold front passes over, temperatures drop and blustery showers may occur.

Water constantly enters and leaves the atmosphere through the water cycle. Water evaporates into water vapor. Water vapor condenses into cloud and precipitation. Rivers and soakage return water to the sea.

• The amount of water vapor in the atmosphere is expressed in terms of relative humidity.

• Types of clouds include brush-like cirrus clouds, "fluffy" cumulus cloud and layered stratus cloud.

• When air is forced to rise, its water vapor condenses and rain may result.

• Relief rain occurs when air is forced to rise up the sides of the mountain.

• Convectional rain occurs when air rises from a warm land surface.

• Frontal (cyclonic) rain occurs when air rises on the warm or cold fronts within depressions.

Weather forecasts are important to farmers, pilots and other professionals.

Information is recorded by satellites, at weather stations, etc. The Irish weather center uses the information to make weather reports.

Measure Temperature- Thermometer - Degrees celsius (C°) - Isotherms
Measure Wind direction- Wind vane - Compass directions
Measure Wind speed- Anemometer & Beaufort scale - Kilometres (km) per hour Forces - Isotachs
Measure Relative humidity- Hygrometer - Percentages
Measure Sunshine- Campbell Stokes recorder - Hours per day - Isohels
Measure Precipitation- Rain gauge - Millimeteres  (mm) - Isohels


The factors that influence the climates of large regions include the following:

• Latitude: the further a place is from the equator, the cooler it is likely to be.

• Distance from sea: coastal lands tend to have temperature climates with small annual temperature ranges. Places far from the sea tend to have warmer summers and much colder winters.

• Prevailing winds: Ireland's prevailing south-westerly winds bring moderate temperatures and much rain.

The factors that influence local climates include:

• Altitude: temperatures decrease with height above the sea level.

• Relief:

- The windward slopes of coastal mountains get relief rain.

- Places with southerly aspects tend to be warmer than places with northerly aspects.

Hot Climates

• Hot deserts are situated on the western sides of the landmasses between 15 degrees and 30 degrees north and south of the equator. They include the Sahara, Kalahari and Australian deserts.

• Hot climates are very dry, hot and have large day-night temperature ranges.

• Vegetation is scarce in hot deserts. Plants adapt to hot, dry conditions by widely spaced and having deep roots. The giant cactus has a spongy interior to absorb water and a waxy skin to help keep the water inside the plant.

• Desertification is the process by which land turns to desert. It especially affects the Sahel regions on the southern fringe of the Sahara.

• Unreliable rain supplies and drought have helped to cause desertification. Overpopulation (which has led to deforestation, overgrazing and over-cultivation) is also a cause. Once soil is bare and exposed it becomes eroded by the wind and desertified.

Desertification has caused farmland losses, famine and mass migration in the Sahel. People try to prevent desertification by planting trees, restricting cattle numbers and irrigating land.

Irrigation is the artificial watering of land.

• Summers are hot and dry because of low latitudes and high pressure. Winds from the Atlantic help to make winters mild and moist.

• Natural vegetation adapts well to the climate. Waxy leaves, thick bark and long roots help plants to survive the hot, dry summer conditions. Most natural vegetation is now cleared for agriculture. Irrigation is commonly used. Overgrazing has resulted in soil erosion.

Climate affects human activities. For example, hot, dry and sunny summers are the basis of a huge tourist industry in Mediterranean lands. Deep snow and calm, dry conditions attract winter tourists to Alpine resorts.

Cold Climates

• Cold climates include boreal and tundra types.

• The boreal lands lie between 50°N and the Arctic Circle. Because of their high latitudes, they have long, cold winters and short summers, cold, northerly winds provide very little precipitation.

• Boreal regions are covered in vast coniferous forests called taiga. Conifers have thick bark, needle-like foliage, downward-sloping branches and shallow roots. These features help trees to survive in cold, dry conditions. Logging is an important activity in the taiga.

Natural vegetation is vegetation is vegetation that has not been planted or adapted by people.

• Climate helps to determine natural vegetation. It provides the moisture and heat needed for vegetation to thrive. Climate also influences soil fertility and this is turn influences vegetation.

Soil

• Soil is a natural resource that has several ingredients. It main ingredients is mineral particles, which are the remains of denuded rock. Micro-organisms help to break down plants remains into humus. Other ingredients are water and air.

• Climate is important in the formation of soil. It provides the agents of weathering and erosion that breaks down rock into mineral particles. It provides water for the soil. It also provides the vegetation that decays to humus. Human activities may help to make the soil more fertile or less fertile.

• Humification is the process by which plant litter decays into humus. __Leaching__is the process by which water emerges through the soil.
  

A soil __profile__is a vertical section through the soil. The A horizon is nearest to the surface and may contain much humus. Below that is the B horizon, which has less and is more stony. The C horizon is mainly bedrock.

Brown soils are found in lowland areas of limited rainfall that were once covered with deciduous forests. They are fertile soils and are suited to arable farming as well as to cattle farming. Podzols are found in rainy uplands that were under coniferous forests. Podzols are grey and infertile and suited mainly to rough grazing. Tropical red soils are rusty-red in colour and are found in hot, wet tropical regions. When cleared of natural vegetation, they may become heavily leached and eroded.

• Soil influences vegetation. It provides nutrients that are needed by plants. The depth of soil also influences the type of vegetation that grows.

• Vegetation influences soil. It provides humus to fertilize the soil. It reduces the effects of leaching. It also helps to prevent soil erosion.

Grid Referencing, Maps & Globalisation

How to get a four-grid reference:
Step 1: give the sub-zone letter.
Step 2: give the two-digit number of the easting on the left side of the square.
Step 3: give the two-digit number of the northing on the bottom side of the square.


Locating a factory

1. Site: choose a large empty site for buildings, car parks and any future expansion of the factory. Level or gently sloping ground is best, because it is easier (and cheaper) to develop.

2. Transport: good roads (or a railway station) nearby could bring raw materials to and finished products from the factory. Workers will also use road and possibly rail transport. A large port nearby might make it easier  to import raw materials or to export finished products. A nearby airport might be useful for the movement of management staff or of light, valuable products.

3. Town: a nearby town would provide workers (but a factory within a town might look ugly. It would also add to traffic congestion, noise pollution and air pollution).
   

Other factors: other factories nearby might provide linkages with new factory. This means they might provide it with raw material or with nearby market for its products. Many modern factories are now located in industrial estates on the outskirts of urban areas.

Urban Planning
some urban areas show evidence of being laid in a planned way. Here are some examples of urban planning:

• There may be evidence of traffic management

• Special zones may be set aside for separate functions, such as housing, industry or shopping.

• Streets will meet at right angles. They may sometimes form an orderly grid system between blocks of buildings.

• Buildings will be laid out in an orderly manner.

• There may be parks or other green areas. These give a sense of space and provide places for people to relax.

• Town squares may serve as central, focal points for urban areas.

• Trees planted along the side of streets offer greenery and shade.
  

Maps

• All maps are drawn to a dingle scale, so we can calculate distance from them. Maps use contours and spot heights to show the precise heights of places. Maps give names of places. Maps indicate the grades  of roads.

Photographs

• Photographs show features realistically. Photographs can indicate weather conditions, crop growth, traffic and other day-to-day information.

Population

• World population has increased unevenly over time. In the beginning, it grew slowly and even fluctuated. Over the past century growth became ever more rapid, resulting in population explosion.

• Natural change in population is calculated by measuring birth rates against death rates.

• The demographic transition model shows that as a country develops, death rates decline and births rates remain high. The result is a population explosion. Following further economic growth, birth rates also decline.

The following factors influence population change:

• As food supplies and __public health__improve, more people live long enough to have more children. Population increases as a result.
  

• Technology, such as farm machinery and medical equipment, has helped to reduce death rates and so to increase population growth.

• Wars kill people and separate husbands from wives. Population decreases as a result.

• Education and equality between males and females as a result in more women having careers outside the home. Birth rates decreases as a result.

Some people take a pessimistic view of future population growth. They believe that the population explosion will continue well into the future. The optimistic view is that, as countries develop economically, their births rates will fall. Population growth will then modify.

A population pyramid can be used to show the age structure and the sex structure of an area. Places with different population structures have contrasting population pyramids. Brazil has a rapidly growing population. Its pyramid has a broad base and a narrow top. Germany has an almost static population. Its population pyramid has a much narrower base and wider top than that of Brazil.

Migration

Migrant:

• one who moves from one place to live in another place.

Internal migrant:

• one who migrates from one part to another part of the same country.

Immigrant:

• one who migrates into a country.

Emigrant:

• one who migrates into a country.

Refugee:

• an immigrant who gets special permission to live in a country because they are being persecuted in their own country.

Asylum seeker:

• an immigrant who applies for permission to be accepted as a refugee.

Individual migrations:

• migrations that are planned and carried out by the migrants themselves. Most migrations are individual migrations.

Organised migrations:

• migrations that are planned and carried out by governments or other powerful groups.

• Push factors, such as overcrowding, might persuade people to leave an area.

• Pull factors, such as economic opportunities, might attract people to another area.

• Population density is the average number of people per square kilometre. It is calculated by dividing population by area. It varies from place to place and in the same place over time. Population densities can vary according to the resources or terrain of areas.

Case study 1

The North Italian Plain is more densely populated than southern Italy. The land is flatter and more fertile in the north and agriculture is more productive there. Transport networks are better developed in the north, as is manufacturing industry.

Case study 2

population densities very considerably throughout County Dublin. Dublin city- the commercial, educational and administrative center of Ireland – is very densely populated. West Co. Dublin contains large satellite towns such as Tallaght. Its population has grown very rapidly in recent years and its population density is high. North Co. Dublin has moderate density. The presence of Dublin Airport and fertile land set aside for market gardening has helped to prevent urban growth there. The Dublin mountains keep population very low in the extreme south of Co. Dublin. Social and historical events also affect population densities.

Case study 1

The population of the West of Ireland grew rapidly before the Great Famine of 1847. During the famine, it dropped dramatically. For 100 years after that, it continued to decline due to emigration. In the 1960's, it stabilized because of improved job opportunities. In recent years it has grown somewhat. Population densities vary within the West. Some rural areas have steep terrain, poor soils and few employments opportunities. People migrate from these lightly populated areas to growing urban centres such as Galway city. Such centres provide jobs as well as educational and recreational facilities.

Case study 2

The coast of Brazil is much more densely populated than the Amazon Basin. This is largely because Portuguese colonists settled and brought African slaves to plantations and cities in coastal areas. The Amazon Basin was not heavily settled by Europeans in the past. It contains only seven per cent of Brazil's population.

Factors of very high population densities:

• overcrowding

• lack of open space

• shortage of clean water

• pollution

Factors of low population densities:

• low marriage rates

• abandonment of agricultural land

• Political and economic isolation

The world can be divided broadly into rich and economically developed North and poor undeveloped South. Most people live in the South, but the North controls 85 percent of the world's wealth. Child mortality is much higher in the south than in the North. Poverty is the main cause of child deaths in the South. Poverty results from a lack of clean water, from malnutrition and from inadequate preventative medicine. These problems, in turn, result in many avoidable deaths. Especially among children. Life expectancy rates are lower in the third world than in the North. High levels of child mortality, the effects of poverty, wars and AIDS all reduce life expectancy levels in many parts of the South.

Settlement

Early Normans settled in the following places in Ireland:

• In the east and south of Ireland, which was closest to England and Wales, from where they came.

• On fertile lowlands that provided plenty of food and wealth.

• Near rivers that provided water and sometimes transport routes and defensive moats.

• In defensive sites near castles or in towns.

Some of these towns developed from old Viking trading ports.

Towns and other urban settlements are dispersed throughout the country in different patterns.

Factors that affect settlement:

Historic and social factors:

Viking towns formed linear patterns along the south and east coasts. Norman towns were dispersed, mainly throughout the east and the south. The primacy of Dublin caused several towns to be clustered around it. Other towns are distributed in linear patterns along roads leading to Dublin.

Physical factors:

Rivers were used for food, transport and safety, which attracted early settlers. They avoided areas that were hilly or at high altitudes.