Tectonics

Question 1

How many cm per year does the Indian plate move toward the Eurasian plate?

Answer 1

5cm

Question 2

What temperature is the earth core

Answer 2

6000°C

Question 3

What is the Nepal case study?
Magnitude 
Year
Cause
Deaths

Answer 3

7.8 magnitude earthquake in 2015
Due to movement of North Indian plate towards Eurasian plate
9000 deaths

Question 4

Explain the process of plate movement due to convection currents.

Answer 4

-6000*C core radiates heat into the mantle non-uniformly
-Areas heated more become less dense and rises until it reaches the lithosphere where it is forced sideways
-friction between mantle and lithospheric crust causes plate movement through convection traction
as mantle at lithosphere cools in sinks back down to the core where it is heated again making a convection current

Question 5

Explain how plate movement leads to tectonic hazards.(earthquakes)

Answer 5

-slab pull and convection currents cause plates to move
-causes plate boundaries to slide past and crash into each other leading to build up of tectonic strain
-pressure exeeds force leading to fault fracture
-energy released in form of seismic waves
leads to earthquake at surface and destruction to buildings and loss of life

Question 6

Explain how slab pull leads to plate movement

Answer 6

• Takes place at oceanic continental boundary
• oceanic plate cooler and denser causing it to sink lower in mantle than the continental plate
• force of gravity and weight of plate drags it into the subduction zone
• oceanic plate subducts beneath he continental plate

Question 7

What is the Iceland case study?(earthquake)

• Boundary type
• year
• magnitude
• deaths/injuries

Answer 7

• Earthquake occurred at divergent boundary
• year 2000
• Magnitude 5.9
• 0 deaths 30 injuries

Question 8

What is the Chile case study?(earthquake)
boundary
year
magnitude
deaths
homes destroyed
focal point

Answer 8

• Earthquake occurred at convergent plate boundary
• year 2010
• magnitude 8.8
• 525 deaths
• 37000 homes destroyed
• focal point 35 km

Question 9

Compare levels of risk for divergent and convergent plate boundaries

Answer 9

-Theory of wadatti-benioff zone
-Convergent boundaries have larger magnitudes and shallower
-Means more energy is release from hypocentre with less distance to dissipate over
-Surface magnitude more intense
-more ground shaking
-more destruction of buildings and more deaths
-convergent higher risk
eg convergent Chile 585 deaths
divergent Iceland 0 deaths(see flashcard)

Question 10

What is the Mt Pinatubo case study?
plates
VEI
Year
Lava type
Deaths

Answer 10

Convergence between oceanic Philippine plate and Continental Eurasian plate in 1991
VEI 6
Lava is andesitic so has higher silica content
Lead to 300 deaths

Question 11

How does the type of crusts affect hazard risk in terms of volcano explosivity

Answer 11

• Explosivity is determined by the type of plate that makes the eruption
  -convergence between oceanic and continental crust produces andesitic lave
  -High levels of silica
  -Higher viscosity
  magma contains more gas
  -more explosive
  -higher risk of more intense hazard(eg pyroclastic flow
  -for example mt pinatubo(see flashcard)

Question 12

What is the Haiti case study? (earthquake) PAR model
Root cause
Dynamic pressure
Unsafe conditions
Deaths
Magnitude
Year
Focal depth

Answer 12

Root cause - low levels of economic development with 72% on less than $2 a day
Dynamic pressure - poverty, residents cant afford earthquake proof housing
Unsafe conditions - weak brittle housing 90% made of weak concrete
Deaths - over 230000 due to collapse of 200000 houses
Magnitude 7.0
Year 2010
Focal depth 13km

Question 13

Explain how mount Pinatubo became a disaster using the deggs model?

Answer 13

• Deggs model shows the relationship between vulnerability and Geophysical hazard creating a disaster
• Mount Pinatubo 1991 eruption vei 6 (see flashcard)
• Vunerable pop did not have slanted rooves
• This meant tephra accumulated on roofs and weight of ash caused buildings to collapse
• lead to 300 deaths

Question 14

Explain how hazard risk formula helps us understand vulnerability compared to the Deggs model?

Answer 14

Breaks down individual components associated with risk
RISK= hazard x exposure x vulnerability/manageability
-features exposure which Deggs model doesn’t
-2010 Haiti earthquake of 7.0 magnitude (see flashcard)
- 25% of of population of Haiti lived in capital Port-au-Prince
-20km from epicentre
-Large proportion of pop would have been impacted which isn’t shown in Deggs model

Question 15

How does the par model allow us to understand root causes leading to vulnerabilities?

Answer 15

• Root cause poor governance in Haiti
• Lack of support in rural areas
• Increase rural urban migration
• 25% pop live in capital which was 20km from epicentre
• furthermore poor building regulations
• buildings have poor foundations and built on hill slopes
• contributed to building collapse