Tectonic Processes and Hazards

Question 1

3 main types of plate boundary

Answer 1

• Constructive, Mid-Atlantic Bridge
• Conservative, Himalayas
• Destructive, Subduction, San Andreas Fault

Question 2

Properties of Oceanic and Continental Crust?
Crust

Answer 2

• Oceanic, Thinner, high density and younger
• Continental, Thicker, low density and older

Question 3

Why is the asthenosphere important?

Answer 3

Allows the tectonic plates to move as the asthenosphere can bend and move

Question 4

What is the Benioff zone?

Answer 4

The area within the subduction zone where most friction and pressure build up occurs

Question 5

How to work out the Interquartile Range?

Answer 5

• Order numbers in order, small to big
• Separate into LQ, IQR and UQ
• Biggest number subtract from smallest in IQR

Question 6

What is Paleomagnetism?

Answer 6

• The magnetic field of Earth vary with time and sometimes flip completely

Question 7

What is slab pull

Answer 7

• Needs subduction
• Weight of sinking cooling plate causes a major pulling action, causes rest of the plate to be pulled downwards

Question 8

What is Crustal Fracturing?

Answer 8

Occurs when the earth’s crust causes rock to break and
fracture under stress and strain caused by seismic stresses

Question 9

Name the primary hazards of volcanoes

Answer 9

• Lava flows
• Pyroclastic flows
• Tephra and ash flows
• Volcanic gases

Question 10

What are the characteristics of P (primary) waves?

Answer 10

• Fastest, first to surface
• Travels through solids and liquids
• Only damaging in most powerful earthquakes

Question 11

What are the characteristics of L (love) waves?

Answer 11

• The slowest and last waves to arrive
• Cause the most damage (ground shakes side to side)
• Larger and focus all energy on the surface

Question 12

What are the 3 main types of seismic waves?

Answer 12

P - Primary (or pressure)
S - Secondary (or shear)
L waves - Love

Question 13

Identify secondary hazards of earthquakes

Answer 13

• Liquefaction
• Landslides
• Tsunamis

Question 14

How are volcanic hotspots created?

Answer 14

• A mantle plume is an upwelling of abnormally hot rock within the Earth’s mantle causing a hot spot on the surface
• the lithosphere melts and allows magma to escape to the surface
• The plume stays where it is as the crust slowly migrates over it leading to the formation of island arcs

Question 15

What is VEI?

Answer 15

• Volcanic Explosivity Index
• Measures how much volcanic material is ejected
• Height of material thrown into atmosphere
• How long eruptions last
• Logarithmic scale, 1 - 10

Question 16

Give three factors that might cause a volcano to be more explosive

Answer 16

Gases, pressure, viscosity/type of magma