hazardous environments

Question 1

What is the risk equation?

Answer 1

risk = (frequency or magnitude of hazard x level of vulnerability)/capacity of population to cope

Question 2

What is the definition of vulnerability?

Answer 2

How susceptible a community is to the damaging effects of a hazard

Question 3

What is meant by ‘capacity to cope’?

Answer 3

The ability of a community to face and manage a disaster

Question 4

What is needed for a tropical storm to form?

Answer 4

• Sea temperature of at least 26 degrees
• Latitudes 5-20 degrees for wind
• Coriolis effect
• Light wind sheers

Question 5

How do hurricanes form?

Answer 5

1. The sun heats the ocean near the equator.
2. This heats the air above it which rises upwards.
3. As the air rises it spins in an anticlockwise direction.
4. The air at the top cools down forming huge cumulo nimbus thunderclouds.
5. These clouds can cause extremely heavy rainfall.
6. The warm water of the ocean continues to drive the hurricane.
7. The centre of the hurricane is a clear, calm area called the eye.
8. Once the hurricane reaches land it does not have the warm waters needed to fuel it. It quickly loses energy.
9. This can cause extreme damage to coastal settlements.

Question 6

How are tropical storms measured?

Answer 6

Saffir-simpson scale which measures the wind speed and the height of the storm surge.

Question 7

What happens at a destructive plate margin?

Answer 7

1. Oceanic crust is denser than continental crust.
2. The oceanic plate subducts because it is denser.
3. A zone of intense friction and pressure is created, called the Benioff zone
4. Here, magma can erupt through fissures.

Question 8

What is an example of a destructive plate margin?

Answer 8

Nazca plate and South American plate

Question 9

What happens at a conservative plate boundary?

Answer 9

1. Plates try to move past each other at different speeds.
2. Plates jam together and pressure builds up.
3. Pressure releases, causing earthquakes.

Question 10

What is an example of a conservative plate boundary?

Answer 10

Pacific plate and North American plate, creating the San Andreas Fault

Question 11

What happens at a constructive plate margin?

Answer 11

1. Two plates move apart.
2. Magma rises up to fill the gap.
3. Magma can escape easily so there is no significant eruption.
4. New land is created (volcanic islands; shield volcanoes)

Question 12

What is an example of a constructive plate boundary?

Answer 12

North American plate and Eurasian plate

Question 13

What happens at a collision plate margin?

Answer 13

1. Two plates move towards each other (both continental crust)
2. They collide.
3. The crust buckles (crumples) and some uplift occurs.
4. This produces mountains.

Question 14

What is an example of a collision plate boundary?

Answer 14

Indian plate and Asian plate, creating the Himalayas

Question 15

How are earthquakes measured?

Answer 15

Richter scale, measures the magnitude from the amount of energy released

Question 16

What is pyroclastic flow?

Answer 16

A high density mix of hot lava blocks, pumice, ash and volcanic gas that moves at high speed down volcanic slopes, typically following valleys

Question 17

What are lava flows?

Answer 17

Streams of molten rock that pour or ooze from an erupting vent

Question 18

What are tephra and ash falls?

Answer 18

Tephra is fragments of rock that are produced when magma or rock is explosively ejected.

Question 19

What are lahars?

Answer 19

A mixture of water and volcanic debris that moves rapidly downstream.

Question 20

What are jokulhlaups?

Answer 20

Refers to the sudden, violent and short-lived increase in discharge of glacial meltwater.

Question 21

What are toxic gases?

Answer 21

Carbon dioxide, sulfur dioxide, hydrogen sulfide, hydrogen halides