Tectonics

Question 1

Distribution of tectonic hazards

Answer 1

Earthquakes = close to plate boundary and around the “ring of fire”

Volcanoes = close to plate boundary, 75% around the “ring of fire”

Tsunamis = 70% in Pacific Ocean

Question 2

Plate boundaries

Answer 2

Divergent - plates moving apart
Convergent - plates moving together
Transform - plates moving past each other or in the same direction at different speeds
Collision = two plates meet and both fold and deform - forced upwards

Question 3

Theory

Answer 3

Wegner = theory of continental drift

Hess = sonar and radar reveal the shape of ocean floors

Wilson = sea floor spreading

Wilson and Hess = theory of plate tectonics by combining sea floor spreading with continental drift

Convection currents = heat from radioactive decay moves upwards, convection currents push up into the ridges forcing them further apart called the ridge push

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

Question 4

Natural Hazards and Disasters

Answer 4

A hazard is an event which has the potential to cause harm to the environment, people or the economy

A natural hazard is an event caused by environmental processes and would occur without the presence of humans

A disaster occurs when harm actually occurs to the environment, people or the economy

Mega-disaster = a high impact/magnitude, infrequent event which impacts many countries directly or indirectly

Question 5

Vulnerability and resilience

Answer 5

Level of development
Population density
Size of hazard
Preparation and planning

Pressure and Release model
Pressure = Root causes, Dynamic pressures, Unsafe conditions
Release = Adressing the pressures and vulnerabilities

Question 6

Hazard profiles

Answer 6

Scales:
Moment magnitude scale (MMS)
Modified Mercalli Intensity Scale
Volcanic explosively index (VEI)

Profiles:
Magnitude
Speed of onset
Areal extent
Duration
Frequency
Spatial predictability

Question 7

Factors affecting impact of hazards and development

Answer 7

Inequality and vulnerability = HDI
Governance = Good or Poor
Geographical factors = Pop density, Isolation, Urbanisation

Question 8

Trends

Answer 8

Global recorded disasters = significantly increased since 1960 due to increased pop, monitoring and reporting

Tectonic disasters = remained stready

Number of deaths = decreased due to improved monitoring, planning, education etc

Economic costs = increased as infrastructure and wealth has increased

Question 9

Theoretical frameworks

Answer 9

Prediction = knowing when (temporal scale) and where (spatial scale) a hazard will occur

Forecasting = Forecasting gives a percentage chance of a hazard occurring over a set period of time

• Cannot predict EQs
• Can predict volcanic eruptions
• Can only predict tsunami after EQ has happened

Hazard management cycle:
- Response
- Recovery
- Mitigation
- Preparedness

Parks model: Disaster response curve
1. Disaster event
2. Search and rescue
3. Relief and rehabilitation may involve help from outside
4. Recovery aimed at reducing vulnerability
5. Strategies implemented to reduce the impact of future events

Curve depends on:
- Preparation and planning
- Development
- Aid both national and International