Tectonic processes and hazards

Question 1

What is a destructive (convergent) plate boundary?

Answer 1

When an oceanic and continental plate converge, so the oceanic plate is forced under the continental plate
Earthquakes along the Benioff zone
Underwater volcanoes
e.g along the West Coast of South America

Question 2

What is a constructive (divergent) plate boundary?

Answer 2

When two plates (usually oceanic) diverge
Rift volacones form (less explosive)
Small, frequent earthquakes
e.g between the Nazca and Pacific plates

Question 3

What is a transform (conservative) plate boundary?

Answer 3

Where two plates move alongside eachother
Powerful, shallow focus earthquakes
e.g between the Pacific and North American plates

Question 4

What is a collison plate boundary?

Answer 4

When two continental plates converge
Earthquakes likely to have a shallow focus
e.g between Altipino and South American plates

Question 5

What are the exceptions to tectonic activity at plate boundaries?

Answer 5

Intraplate earthquakes (e.g the New Madrid seismic zone, US) or hotspot volcanoes (e.g Hawaiian volcanoes)

Question 6

What is a primary (P) wave?

Answer 6

Body waves
Spread quickly from a fault
Can travel through liquid, so every layer of the earth
Least destructive

Question 7

What is a secondary (S) wave?

Answer 7

Body waves
Can only travel through solid rock
Slower than P-waves

Question 8

What are Love waves?

Answer 8

Surface waves
Have a high amplitude and travel quickly
Cause the most damage to buildings (shaking side-to-side)

Question 9

What are Rayleigh waves?

Answer 9

Surface waves
Have a rolling motion
Most of the shaking felt is due to these

Question 10

What is the Pacific Ring of Fire?

Answer 10

An area known for its string of volcanoes and seismically active sites. Along much of the Ring of Fire, plates meet at convergent boundaries (subduction zones)

Question 11

Why are there lots of tsunamis in the Pacific?

Answer 11

Because plate boundaries are convergent, which is where the biggest earthquakes occur

Question 12

Is it possible to predict tsunamis and provide early warning systems?

Answer 12

It is impossible to predict a tsunami because it is impossible to predict earthquakes
But it is possible to provide an early warning system (e.g Indian and Pacific oceans)

Question 13

Why was the Indian Ocean Tsunami warning system established?

Answer 13

The early warning system was implemented after the 2004 Boxing Day Tsunami in the Indian Ocean. At least 225,000 died across a dozen countries

Question 14

What is Degg’s model?

Answer 14

Shows that a natural disaster only occurs if a vulnerable population is exposed to a hazard

Question 15

How does human geography relate to hazards?

Answer 15

Human geography tells us important factors that contribute to a country’s ability to cope with hazards e.g a poor country will be more vulnerable to hazards because they have less money to invest in to health care

Question 16

What is a multiple-hazard zone? (MHZ)

Answer 16

An area at risk from multiple natural hazards (e.g. California, the Philippines, Japan)

Question 17

Why is it important to name MHZs?

Answer 17

Because a country may get more support from international aid agencies and more resources to help with hazard management

Question 18

Why are large urban areas often zones of multile-hazard risk?

Answer 18

They are centres of economic development
Rapid urbanisation (sometimes poor quality housing)
High population densities

Question 19

Why is the Philippines a multiple-hazard zone?

Answer 19

It sits across a major convergent plate boundary (both earthquakes and volcanoes)
Its northern and eastern coast face the Pacific (most tsunami-prone ocean)
It has a tropical monsoon climate (heavy annual rain = floods, landslides, exarcerbated by steep topography and deforestation)
There are about 24 active volcanoes

Question 20

What human factors also but the Philippines at risk?

Answer 20

It is an emerging country. Rapid urbanisation and population growth
Many of the poor live in coastal areas - poorly constructed houses and infrastructure - sea surges, flooding, tsunamis

Question 21

Case study examples of hazards in the Philippines?

Answer 21

2013 Bohol earthquake - landslides, soil liquefaction
Typhoon Haiyan 2013 (just 3 weeks later)

Question 22

What are the stages of the hazard management cycle?

Answer 22

Mitigation - preventing hazards/minimising their effects
Preparedness - preparing to deal with a hazard event
Response - responding effectively
Recovery - getting back to normal

Question 23

What does the Park Model show?

Answer 23

How a country responds to a hazard event, how long it will take to recover

Question 24

What are advantages of the Park model?

Answer 24

It is easy to interpret
It enables different events to be compared

Question 25

What are limitations of the Park model?

Answer 25

It is generalised
It does not account for differences in development, carying capacity to respond (some countries will need external support)

Question 26

What are the 3 strategies to manage hazards?

Answer 26

Strategies to modify the event e.g diverting lava flows
Strategies to modify vulnerability and resilience e.g prediction of events
Strategies to modify loss e.g emergency aid

Question 27

What are examples of strategies to modify the event

Answer 27

Land use zoning
Hazard-resistant design and engineering defences
Diversion of lava flows - cannot predict lava flow but was succesful for Mount Etna 1983
GIS to identify hazard risk zones

Question 28

What are examples strategies to modify vunerabilty and resilience?

Answer 28

High tech monitoring - over 4000 seismometers around Japan
Prediction
Education - Japan Disaster Preventation Day September 1st
Community preparedness and adaptation

Question 29

What are examples of strategies to modify loss?

Answer 29

Aid (emergency, short-term, long-term)
Insurance
Actions of affected communities - crucial in search-and-rescue efforts