Unit 2 - Natural Environment: Tectonic landscapes

Question 1

where are earthquakes found?

Answer 1

along the three types of plate boundaries, convergent, conservative and divergent. On the Land and in the sea.

Question 2

Where is the largest plate and the largest belt?

Answer 2

The Pacific plate is the largest plate, home to the pacific ring of fire

Question 3

define hotspots?

Answer 3

volcano centered in the middle of plates because of the weakness of the crust.

Question 4

Summarize plate tectonics and the importance of the earths crust.

Answer 4

the earth is divided into 7 large and 12 small plates that make up the earths crust, they are floating on a sea of magma, its cooler rock floating on warmer rock. the earths crust can range from 10-100km thick. Can be described as a egg and we are living on the shell.

Question 5

How can the earth be compared to an egg?

Answer 5

If you boil an egg and it cracks it will crack into jigsaw like pieces. However the shell will be alot thicker in terms of scale, for an egg it would be like a post stamp.

Question 6

What are the two types of crust and what are they like?

Answer 6

Oceanic crust is between 5 and 10km think so it is fairly thin, how ever it is heavier and more dense the continental crust and it is constantly being renewed or destroyed.
Continental crust is between normally 25-100km thick, alot thicker that oceanic. However it is less dense so weaker, so it does not sink down into the magma. it is not destroyed

Question 7

how do the move?

Answer 7

they move in the three types of plate movement.

Question 8

what are the three types of plate movement?

Answer 8

some plates move towards each other such as destructive convergent boudires e.g. Nazca and South American plates, Some plates move away from each other divergent constructive e.g. Nazca and Pacific. And some slide past each other conservative transform boundires, e.g. Pacific and North American.

Question 9

What happens when these plates meet and what can be found?

Answer 9

the plates meet and boundaries or plate margins, these are giant plate stress points, this is where most of the worlds earthquakes and volcanoes occur as well as other features such as fold mountains such as the Himalayas and rift valleys.

Question 10

Define rift valleys?

Answer 10

a steep-sided valley formed by the downward displacement of a block of the earth’s surface between nearly parallel faults or fault systems.

Question 11

Define fold mountains?

Answer 11

Fold mountains are mountain ranges that are formed when two of the tectonic plates that make up the Earth’s crust push together at their border. The extreme pressure forces the edges of the plates upwards into a series of folds.

Question 12

Where is the most active belt?

Answer 12

Pacific ring of fire

Question 13

What are hotspots?

Answer 13

Island chains such as SAMOA and HAWAII are know as hotspots, they are when magma from the earths mantel erupts through the crust. This then creates a volcano that rises through the surface forming a island.

Question 14

How are hotspots formed?

Answer 14

weaknesses in the crust give way and volcanoes are formed that create islands.

Question 15

How are island chains formed?

Answer 15

this is when a hotsport in formed on one island, however the plate will keep moving, so another volcano will form creating a new island next to the first island, this happens again and again to create an island chain.

Question 16

Explain what is happening on DESTRUCTIVE (CONVERGENT) boundaries ocean to ocean

Answer 16

this is when two plates moving towards each other and then subduct (one goes under the other) The cause of subduction is when one plate is less dense then the other. the heavier one is pushed under the lighter one. E.G. Philippine plate subducts under the Eurasian plate. Volcano occur when subduction because there is a lot of pressure being built up and also because of this there are high strength earthquakes.

Question 17

What is the cause of SUBDUCTION?

Answer 17

This is when a heavy plate is pushed under a lighter plate because it is more dense.

Question 18

Explain what is happening on DESTRUCTIVE (CONVERGENT) ocean to continent.

Answer 18

This is when the denser and thiner ocean plate sinks below the lighter thicker continental plate, fold mountains can be found here. For example the Nazca plate being sub ducted under the South American plate.

Question 19

Can volcanos be found Destructive (Convergent) Ocean to continent boundaries?

Answer 19

Yes- the oceanic plate will have water in so when the plate is sub ducted then the water will heat up and evaporate, this cause pressure that rises to the surface and forms a volcano

Question 20

Can earthquakes be found Destructive (Convergent) Ocean to continent boundaries?

Answer 20

Yes large earthquakes- a lot of pressure can be built up when plates are sub ducted

Question 21

Explain what is happening DESTRUCTIVE (CONVERGENT) boundaries- continental to continental.

Answer 21

Continental crust is a lot less dense the oceanic crust, this means that the rocks simply fold on each other. It is a slow collision and causes a big land fold up, an example of this would the the Indian plate pushing against the eurasian plate forming the HIMALAYAS

Question 22

Do volcanos occur on DESTRUCTIVE (CONVERGENT) boundaries- continental to continental.

Answer 22

No, because it is causing and fold, the mantel is not involved

Question 23

What strength earthquakes occur on DESTRUCTIVE (CONVERGENT) boundaries- continental to continental.

Answer 23

High, because the crust is folding causing a large pressure build up and when the pressure is released there are large earthquakes.

Question 24

Explain what is happening on DIVERGENT (CONSTRUCTIVE) boundaries

Answer 24

This occurs when to plates are moving apart, it creates a ridge and new land is formed, when magma form the mantle forms new crust , sometimes volcanos form new islands as they move. For example the islands on the mid atlantic ridge.

Question 25

Do volcanos occur on DIVERGENT (CONSTRUCTIVE) boundaries

Answer 25

Yes, this is because new land is being formed

Question 26

Do earthquakes occur on DIVERGENT (CONSTRUCTIVE) boundaries

Answer 26

No, this is because there is no pressure build up.

Question 27

Define Destructive margin?

Answer 27

When one plate sinks under another (subducts)

Question 28

Define constructive margin?

Answer 28

When to plates are moving away form another so new land is being formed

Question 29

Define conservative margin?

Answer 29

When two plates move past each other.

Question 30

Define collision margin?

Answer 30

When two continental plates move together

Question 31

Explain what happens on CONSERVATIVE (transform) boundaries?

Answer 31

Here there are two plates moving in different directions, not much really happeing, the two plates simply just slide past each other. An example of this would be the San Andreas Fault in north america

Question 32

Do earthquakes occur on CONSERVATIVE (transform) boundaries?

Answer 32

Yes, medium to low, this is because the plates can sometimes catch on each other can pressure can build up, when released an earthquake occurs.

Question 33

Do volcanos form on CONSERVATIVE (transform) boundaries?

Answer 33

No because crust is not being lost or formed

Question 34

What are the two ways in which earthquakes are measured?

Answer 34

The Mercalli Scale

The Richter Scale

Question 35

How does the Mercalli scale work?

Answer 35

The intensity of an earthquake is measured by the violence of the earths motion that was produced by the quake, they do this by asking people and looking at buildings. The scale is the earthquakes effect on humans. It is not as accurate as the Richter scale.

Question 36

Which places have adopted the Mercalli scale?

Answer 36

Many places including Hong Kong have adoppted the scale, the scale has 12 grades

Question 37

Are there any problems with the Richter scale?

Answer 37

The scale may not be accurate because buildings may be better made in certain places etc..
Also is it no use in places such as the desert and rainforest etc… Because there are no buildings

Question 38

How does the Richter scale work?

Answer 38

The Richter scale works by measuring energy released via instruments mainly SEISMOGRAPHS which measure vibrations. This way it be a lot more accurate then the Richter scale. As you go up on the Richter scale it has a 10 fold increase, so a magnitude 7 eathquake is 10 times then a 6 and 100 times more powerful then a 5.

Question 39

How does a seismograph measure earthquakes?

Answer 39

It measures the energy caused by the quake in waves, the biggest wave is then then the strength of the earthquake.

Question 40

What is the epicentre and focus of an earthquake?

Answer 40

The earthquake is caused by a large release of a large amount of pressure, the point in which the energy is released is called the focus. The point of the earths surface directly above the focus is called the epicentre, this is where the greatest damage occurs and the damage decreases the further you are away form the epicentre.

Question 41

Why are there so few earthquakes in the UK.

Answer 41

This is because the UK is right in the middle of a plate, we are near no plate boundires, thsi means not crust is being destroyed or made. We are along way from the epicentre so we hardly feel it is there are earthquakes at the boundaries. The closet plate boundires are the eurasion divergent boundries, they dont have strong earthquakes anyway.

Question 42

Why do people continue to live in areas of earthquake activity, economic reasons?

Answer 42

This is because of the fact that people feel that it is to expensive to more, or they have work in the place they are living in currently and will not be able to get work anywhere else.

Question 43

Why do people continue to live in areas of earthquake activity, social reasons?

Answer 43

In Japan lots of people in LIC’s, so many people can’t move or don t want to move because of family or they can t afford to. This is normally where they have been all there lives. Also many people pray to the earthquake gods so they will not move.

Question 44

Why do people continue to live in areas of earthquake activity, environmental reasons?

Answer 44

In Malibu, California some people feel safer because buildings are built earthquake proof.

Question 45

Why do people continue to live in areas of volcanic activity, economic reasons?

Answer 45

In Naples,Italy the soil is very fertile and is good for growing crops thats why so many people do.
On Mount Mayon, Philippines, 20,000 people live there sonit is a good place to make money.
In colombia, the worlds best coffee is made on the slopes of this volcano.

Question 46

Why do people continue to live in areas of volcanic activity, social reasons?

Answer 46

On Mount Merapi, many people often worship the sprites of the volcano, they think that they will be warned of an eruption before it happens
Many people climb to the crater and throw in valuables for good luck.

Question 47

Why do people continue to live in areas of volcanic activity, enviromental reasons?

Answer 47

On Mount Etna, Sicily. The Mountain is a popular tourist destination
Many people often travel up and down the volcano in a cable car
Many tourists facilities give the locals lots of jobs

Question 48

Case study, deaths?

Answer 48

18,000- mostly because of buildings collapsing

Question 49

Case study, homeless

Answer 49

300,000- were living in temporary accommodation because of the quake destroying there homes.

Question 50

Case study, buildings destroyed

Answer 50

65,000- Most common type of house in turkey 2-5 story town houses are not built well so were easily destroyed.

Question 51

Case study, Area affected?

Answer 51

The destruction occurred over a large area, much devastation occurred over 100miles form Istanbul.

Question 52

Case study, Motorways

Answer 52

Parts of a motorway between Ankara and Istanbul buckled, causing damages, injuries and crash collisions.

Question 53

Case study, Hospitals?

Answer 53

Hospitals ran out of beds, this caused more pain and discomfort

Question 54

Case study, traffic jams?

Answer 54

Solid traffic jams, because people were trying to leave the area along the main roads around the capital.

Question 55

Case study, tidal surge?

Answer 55

6m high wave, a wave swept into the costal areas of lzmit Bay on the Sea of Marmara, smashing buildings, boats etc.. The wave was rebounding of the nearby mountains and hills for hours

Question 56

Case study, temporary accommodation?

Answer 56

20,000 two years after the quake this many people were still living in temporary accommodation.

Question 57

Case study, Psychological problems?

Answer 57

People now even if there are small earthquakes will run out in the streets screaming, because they are mentally scared for life.

Question 58

Case study, worse hit regions?

Answer 58

The worst hit areas were the eastern end of the sea of Mumara, this is a very large industrial area, big businesses recovered quickly however small business have been forced to shut down also many of there customers have moved away from the quake region or have now got no money to spend.

Question 59

Environmental impacts, Tupras

Answer 59

There was a large fire at turkeys largest oil refinery, 700,000 tonnes of oil caught fire, so there was a large amount of pollution, people started have breathing problems, this caused a large impact on the environment.

Question 60

Environmental impacts, Korfez?

Answer 60

In Turkey the oil rig was still on fire, and it caused lots of damage to the local ecosystem.

Question 61

Environmental impacts, Yalova?

Answer 61

In turkey Yalova next to a chlorine plant there was a factory producing fibres, there was leak, this was a danger to the environment, however it was quickly bought under control.

Question 62

Environmental impacts, Sea of Marmara?

Answer 62

The quake caused a large land movement on the cost as a result some land was reclaimed by the sea, homes were lost and, rising sea levels.

Question 63

Environmental impacts, Petkim?

Answer 63

The toxic waste dump at Petkim cracked releasing lots of waste that had been kept there for ages, there was also damage to the nearby water treatment plant, chemicals leaked into the river killing lots of fish.

Question 64

Environment effects, widespread effects?

Answer 64

People began to suffer from illness due to lack of clean water and also because of sewage leaks, many disses such as cholera were spreading quick also, animals such as fish were dieing because of the pollution

Question 65

Montserrat eruption, effects on people?

Answer 65

Large impact on people, exclusion zone set up, people were not allowed to go in because of danger, most people evacuated to north of island (living in makeshift shelters) however some people stayed because they wanted to. These people did not hear the volcaneo sireen so they put them selves at risk (19 people were killed in pyroclastic flows) many people were also burned by braething in the hot gasses. 11,000 were living on the island before the eruption, 7,000 were evacuated, 3,000 to neighbouring islands and the rest to the UK and USA

Question 66

Montserrat eruption, effects on transport?

Answer 66

The island was cut off by all access in 1995 when the volcano destroyed Bramble airport, it was not until the new Gerald’s airport was opened in 2005 flights could continue. Winair offers flights to Antigua and to St Maarten, the tourist industry suffered no one came to the island, when the volcano erupted people tried to escape in there cars but the ash was so thick and there roads were so hot that it just broke the cars.

Question 67

Montserrat eruption, effects on buildings?

Answer 67

Many villages were effected by deposits: Dyer, Streatham, Riley’s Yard etc… Most were completely buried and over 150 house were destroyed, it was so hot that metal window shutters melted and twisted. Houses were also destroyed because they were hit by rocks. 15 people were also still loving in the exclusion zone these were mostly farmers, these farmers died because the best land to farm on was near the volcano.

Question 68

What is the inner core?

Answer 68

The inner core is in the centre and is the hottest part of the Earth. It is solid and made up of iron and nickel with temperatures of up to 5,500°C. With its immense heat energy, the inner core is like the engine room of the Earth.

Question 69

What is the outer core?

Answer 69

The outer core is the layer surrounding the inner core. It is a liquid layer, also made up of iron and nickel. It is still extremely hot, with temperatures similar to the inner core.

Question 70

What is the mantle?

Answer 70

The mantle is the widest section of the Earth. It has a thickness of approximately 2,900 km. The mantle is made up of semi-molten rock called magma. In the upper parts of the mantle the rock is hard, but lower down the rock is soft and beginning to melt.

Question 71

What is the crust?

Answer 71

The crust is the outer layer of the earth. It is a thin layer between 0-60 km thick. The crust is the solid rock layer upon which we live.

Question 72

What is continental crust?

Answer 72

continental crust, which carries land.

Question 73

What is oceanic crust?

Answer 73

oceanic crust, which carries water.

Question 74

What are convectional currents?

Answer 74

The Earth’s crust is broken up into pieces called plates. Heat rising and falling inside the mantle creates convection currents generated by radioactive decay in the core. The convection currents move the plates. Where convection currents diverge near the Earth’s crust, plates move apart. Where convection currents converge, plates move towards each other. The movement of the plates, and the activity inside the Earth, is called plate tectonics.

Question 75

How do earthquakes occur?

Answer 75

Earthquakes occur when tension is released from inside the crust. Plates do not always move smoothly alongside each other and sometimes get stuck. When this happens pressure builds up. When this pressure is eventually released, an earthquake tends to occur.

Question 76

Social, short term impacts of earthquakes?

Answer 76

People may be killed or injured. Homes may be destroyed. Transport and communication links may be disrupted. Water pipes may burst and water supplies may be contaminated.

Question 77

Short term, economic impacts of earthquakes?

Answer 77

Shops and business may be destroyed. Looting may take place. The damage to transport and communication links can make trade difficult.

Question 78

short term, environmental impacts of earthquakes?

Answer 78

The built landscape may be destroyed. Fires can spread due to gas pipe explosions. Fires can damage areas of woodland. Landslides may occur. Tsunamis may cause flooding in coastal areas.

Question 79

Long term, social impacts of earthquakes?

Answer 79

Disease may spread. People may have to be re-housed, sometimes in refugee camps.

Question 80

economic, long term impacts of earthquakes?

Answer 80

The cost of rebuilding a settlement is high. Investment in the area may be focused only on repairing the damage caused by the earthquake. Income could be lost.

Question 81

Long term, environmental impacts of earthquakes?

Answer 81

Important natural and human landmarks may be lost.

Question 82

Factors effecting the impact of an earthquake?

Answer 82

• Distance from the epicentre - the effects of an earthquake are more severe at its centre.
• The higher on the Richter scale, the more severe the earthquake is.
• Level of development (MEDC or LEDC) - MEDCs are more likely to have the resources and technology for monitoring, prediction and response.
• Population density (rural or urban area). The more densely populated an area, the more likely there are to be deaths and casualties.
• Communication - accessibility for rescue teams.
• Time of day influences whether people are in their homes, at work or travelling. A severe earthquake at rush hour in a densely populated urban area could have devastating effects.
• The time of year and climate will influence survival rates and the rate at which disease can spread.

Question 83

Warning signs an volcano is going to erupt?

Answer 83

• Hundreds of small earthquakes are caused as magma rises up through cracks in the Earth’s crust.
• Temperatures around the volcano rise as activity increases.
• When a volcano is close to erupting it starts to release gases. The higher the sulfur content of these gases, the closer the volcano is to erupting.

Question 84

Monitoring techniques to see if a volcano is going to erupt?

Answer 84

• Seismometers are used to detect earthquakes.
• Thermal imaging techniques and satellite cameras can be used to detect heat around a volcano.
• Gas samples may be taken and chemical sensors used to measure sulfur levels.

Question 85

Ways in which earthquakes can be predicted?

Answer 85

• Strain meter to monitor stress changes in the rocks.
• creep meter to monitor small movements in the earth along the fault.
• well levels to monitor ground water movements.
• Unusual animal behavior has been observed.
• Tilt meters and gravity meter to detect changes in the local magnetic field and minor earth movements.
• Monitor changes in the height of the water table.
• Lasers can be used to detect small amounts of movement.

Question 86

In what ways can we prevent the damage of earthquakes?

Answer 86

Monitoring ground movements - to identify possible seismic activity (as discussed above)

• Earthquake proof modern buildings - this may include reinforcement of foundations; counter-weights; and use of fireproof construction materials. (see here for animation on buildings resisting earthquakes)
• Building Regulations - avoid building on unstable ground (such as landfill) to avoid liquefaction
• Practice Disaster Routines - annual earthquake drills - e.g. San Francisco - April 18th (also see this news article on Japan’s quake drill)
• Automatic shut off switches - for gas mains - to try and minimise the likelihood of fire
• Public Education - public information posters / information on emergency procedures / preparing house / survival kits etc. (e.g. Is Your Home Protected from Earthquake Disasters?)
• Strengthen Routeways - strengthen foundations of bridges / suspended roadways etc.
• Emergency Service Planning - ensure emergency services (medical and rescue) are fully trained to cope with such a disaster and that specialist emergency equipment is available.

Question 87

Case studies Tectonics?

Answer 87

Montserrat - Volcano

Turkey - earthquake