Tectonic Processes and Hazards

Question 1

What is a Hazard?

Answer 1

A potential threat to human life and property

Question 2

Where do Geophysical hazards occur?

Answer 2

Near plate boundaries

Question 3

What is it called when Earthquakes occur near the middle of plates?

Answer 3

Intraplate Earthquakes

Question 4

There are two main sub-sections of Natural Hazards. What are they called?

Answer 4

• Hydro-meteorological
• Geophysical

Question 5

What are Hydro-meteorological hazards?

Answer 5

Hazards caused by climatic processes

Question 6

What are Geophysical hazards?

Answer 6

Hazards caused by land processes

Question 7

Name types of Hydro-meteorological Hazards:

Answer 7

• Floods
• Droughts
• Cyclones
• Blizzards

Question 8

Names types of Geophysical Hazards:

Answer 8

• Earthquakes
• Volcanic Eruptions
• Sinkholes
• Tsunamis

Question 9

Name the layers of Earth’s structure from the outermost to innermost layer:

Answer 9

1) Crust
2) Mantle
3) Outer Core
4) Inner Core

Question 10

What is the difference between Oceanic and Continental Crust?

Answer 10

• Oceanic is thin and dense
• Continental is thick

Question 11

What was Holmes Theory in 1929?

Answer 11

Radioactive Reactions occur in the Core, which produce Convection Currents in the Mantle. This is the force behind Continental Drift.

Question 12

What was Alfred Wegener’s theory in 1912?

Answer 12

All continents were once joined in a super-continent called Pangea, however Continental Drift caused it to split apart. This is further verified by similar fossils found where these plates could have fit.

Question 13

What is the Wadati-Benioff zone?

Answer 13

A dipping flat zone of Earthquakes that is produced by the subduction of Oceanic Plate under a Continental Plate

Question 14

When does Sea Floor Spreading occur?

Answer 14

It occurs when two Oceanic Plates move away from each other, allowing magma from the mantle to rise and form new crust ridges within the ocean, resulting in the sea floor widening.

Question 15

What is Palaeomagnetism?

Answer 15

The study of magnetic patterns in cooled magma within the sea floor that allign with the Earth’s magnetic field, and they reverse over millions of years. This helps date Oceanic crust and proves that the Earth did once fit together.

Question 16

Name the 3 types of Plate Boundaries?

Answer 16

• Divergent
• Convergent
• Conservative

Question 17

Describe a Continental to Oceanic Convergent Plate Boundary:

Answer 17

• The denser Oceanic Plate subducts below the Continental
• The plate subducting leaves a deep ocean trench
• Built up pressure from the melting plate cause explosive volcanoes bursting through the Continental Plate

Question 18

Describe an Oceanic to Oceanic Convergent Plate Boundary:

Answer 18

• The heavier plate subducts leaving an ocean trench
• Built up pressure causes underwater volcanoes bursting through Oceanic Plate
• Lava cools and creates new land called Island arcs

Question 19

Describe a Continental to Continental Convergent Plate Boundary:

Answer 19

• Both plates are not as dense as Oceanic Plates so lots of pressure builds up
• Ancient Oceanic Crust is subducted slightly, but there is no subduction of Continental Crust
• Pile up of Continental Crust on top of lithosphere due to pressure between plates
• Fold mountains formed from piles of Continental Crust

Question 20

Describe an Oceanic and Oceanic Divergent Plate Boundary:

Answer 20

• Magma rises in between the gap left by the two plates separating, forming new land when it cools
• Less explosive underwater volcanoes formed as magma rises
• New land forms on the ocean floor by lava filling the gaps, which is known as sea floor spreading

Question 21

Describe a Continental and Continental Divergent Plate Boundary:

Answer 21

• Any land in the middle of the separation is forced apart, causing a rift valley
• Volcanoes form where the magma rises
• Eventually the gap will most likely fill with water and separate completely from the main island

Question 22

What is Ridge Push?

Answer 22

The slope that is created when plates move apart has gravity acting upon it as it is at a higher elevation. Gravity pushes the plates away, widening the gap.

Question 23

What is Slab Pull?

Answer 23

When a plate subducts, the plate sinking into the mantle pulls the rest of the plate with it, causing further subduction.

Question 24

Describe a Conservative Plate Boundary:

Answer 24

Between any Crust, the parallel plates move in different directions or at different speeds. No plates are destroyed, so no landforms are created.

Question 25

Name the types of Seismic Waves:

Answer 25

1) Primary Waves
2) Secondary Waves
3) Love Waves
4) Rayleigh Waves

Question 26

Name the two types of Plates on the Earth’s Crust?

Answer 26

Oceanic and Continental

Question 27

What is a Disaster?

Answer 27

When a hazard affects human wellbeing

Question 28

What does Degg’s Disaster Model suggest?

Answer 28

A disaster only happens when a hazardous event meets a vulnerable population