Tectonics

Question 1

Describing the pattern of volcanoes and earthquakes

Answer 1

1. Plate boundaries
2. Linear
3. Anomalies (hotspots - middle of plate)
4. (Often along a coast)

Question 2

Divergent plate boundaries

Answer 2

1. Mid-Atlantic Ridge
2. Atlantic Ocean - North American plate + Eurasian plate
3. Moving away from each other
4. Creates a gap
5. Magma rises (to fill the gap)
6. Magma solidifies
7. Forms new land
8. Creates (small) volcanoes
9. Iceland (new land)

Question 3

Convergent plate boundaries

Answer 3

1. Nazca plate (oceanic) + South 2. American plate (continental)
2. Moving towards each other
3. Destructive plate boundary (oceanic-continental)
4. Oceanic = more dense
5. Continental = less dense
6. Oceanic plate is syndicated
7. Causes friction and heat
8. Violent earthquakes (high magnitude)
9. Oceanic plate melts - rock melts
10. Liquid magma caused
11. Magma rises
12. Violent earthquakes (on surface)
13. Fold mountains

Question 4

Conservative/passive

Answer 4

1. San Andreas fault line
2. North American plate and Pacific plate moving past each other
3. Jolting/jerking movement - rock gets locked and stuck
4. Rock gives way (focus)
5. Release of energy from focus releases seismic waves
6. Causes earthquakes on surface

Question 5

Hotspots

Answer 5

1. Mid-plate where magma rises to the surface causing a magma plume
2. This is because the material (magma) is less dense than the surrounding mantle
3. Causes the surface/crust to come and when the magma finds a weakness (in the rock) it will erupt on the surface
4. This has to repeat before you see the volcano on the surface (repeated eruptions)
5. Hawaii

Question 6

3 reasons why people live next to volcanoes

Answer 6

1. Ash turns into fertile soil, which has many nutrients for planting crops and farming (Vesuvius - oranges)
2. Doesn’t happen often - good job = stay (Japan, Hawaii)
3. Minerals like diamond + tin = sell them for money (e.g. Chile)
4. Volcanoes create good tourist jobs = money (e.g. Iceland)

Question 7

Why people life in places where earthquakes occur

Answer 7

1. Doesn’t happen often and people value their jobs more than the dangers (e.g. Hawaii)
2. Houses are built with good foundations - people think it’s safe to stay (e.g. San Francisco)
3. People don’t have enough money to move (LICs)

Question 8

How to measure earthquakes

Answer 8

1. Mercalli scale - measures the damage + impact on people

2. Richter scale - measures magnitude

Question 9

Focus

Answer 9

Where the rock gives way

Question 10

Epicentre

Answer 10

The point on the surface directly above the focus - strongest seismic waves

Question 11

Magnitude

Answer 11

The strength/amount of energy the earthquake has

Question 12

Predicting earthquakes

Answer 12

1.
2.
3.

Question 13

Predicting volcanoes

Answer 13

1.
2.
3.

Question 14

Building design (earthquakes)

Answer 14

1.

2.

Question 15

Prevention of earthquakes

Answer 15

1.

2. Japan Earthquake day (Disaster prevention day = 1st september)

Question 16

Preventing volcanoes

Answer 16

1. Earth walls
2. Water spraying
3. Detonating explosives

Question 17

Reasons for earthquake (case study)

Answer 17

IZMIT

1. Convergent plate boundary (Eurasian plate, African plate, Arabian plate)
2. All of the plates are pushing the small Turkish microplate
3. Turkey lies on the North Anatolian Fault (870km long and one of the most active in the world + conservative plate boundary)
4. The Turkish microplate shifted 2-5m, causing seismic waves that disturbed the fault
5. 17th august 1999 + magnitude 7.4
6. Ground in IZMIT = soft, thick clay + loose sand layers

Question 18

Effects of earthquake (case study)

Answer 18

1. 18000 deaths + 300000 homeless
2. 65000 buildings destroyed (Yalova)
3. Hospitals in Gebze ran out of beds
4. Motorway between Istanbul + Ankara buckled
5. Traffic jam in Golchuk = vigilantes kept roads open for emergency vehicles
6. Tidal surge - Izmit Bay + Sea of Ankara - drowned tourists + marooned passenger ferry
7. Wave struck Degirmendere was 6m high = all but 1 sculpture was destroyed
8. 2 years after earthquake = 20000 people living in temporary accommodation
9. Psychological problems
10. Industrial heartland = shops closed down - $10 billion

Question 19

Environmental effects of earthquake (case study)

Answer 19

1. Factory next to a chlorine plant - producing synthetic fibers - had a chemical leak
2. Massive land movements on coast = land was reclaimed from the sea
3. Lack of clean water = diarrhea
4. Toxic waste dump at Petkim was cracked = exposed waste that was held there for 3 years
5. Oil refinery at Korfez = burning out of control - caused damage to local ecosystem
6. Largest oil refinery at Tupras with 700,000 tonnes of oil = set on fire - caused breathing problems + polluted the area heavily

Question 20

Reasons for earthquake (case study)

Answer 20

1. Montserrat = situated on destructive plate boundary
2. North American plate (oceanic) + Caribbean plate (continental)
3. North American plate = more dense - being subducted
4. Convection currents pull the dense plate into the mantle
5. Intense heat + friction melts the rock = molten rock is lighter than that surrounding it - it is forced upwards
6. Andesite spills out onto surface
7. Andesite forms a dome over the crater
8. Dole eventually collapses = pyroclastic flow + massive ash cloud (10km)