Hazards

Question 1

Define a hazard

Answer 1

Something that is a potential threat to human life or property

Question 2

What are the 3 types of natural hazards

Answer 2

Geophysical

Atmospheric

Hydrological

Question 3

Define vulnerability

Answer 3

How susceptible a population is to the damage caused by a hazard

Question 4

Define Magnitude/Intensity

Answer 4

How powerful the hazard is

Question 5

What does the park model show

Answer 5

The different phases of response to a hazard

Question 6

What is the asthenosphere

Answer 6

The upper mantle layer of the earth
Semi molten

Question 7

What is ash

Answer 7

Fine particles and dust ejected during an eruption

Question 8

what is continental crust

Answer 8

Crust that forms the continents of the lithosphere

Question 9

Describe continental drift

Answer 9

Movement of tectonic plates due to varying weights of crust caused by slab pull

Question 10

What is the epicentre

Answer 10

The point on the surface, directly above the earthquake

Question 11

Define fatalism

Answer 11

The belief that hazards are uncontrollable, so losses should be accepted and mitigation is unnecessary

Question 12

What is the focus

Answer 12

The place in the crust where the energy is released

Question 13

What is a hotspot

Answer 13

Volcanoes found away from plate boundaries due to magma plumes close to the surface

Question 14

What is a lahar

Answer 14

A flow of mud and debris

Question 15

What is the lithosphere

Answer 15

The upper crust of the earth

Question 16

Outline the process of liquification (4)

Answer 16

Sediment loses strength and stiffness as a response to a stress

Solid material behaves like a liquid

Requires a degree of saturation to occur

Can cause damage to infrastructure and cause buildings to collapse

Question 17

Outline the concept of hazard management cycle

Answer 17

A continuous loop which explains the approach to managing a hazard

Preparedness is concerned with using evidence and data from previous events to plan for hazards

Good preparation minimises impacts from a hazard

Response ensures providing medical aid and services to save and help people

Question 18

Outline the factors which lead to the formation of mudflows (4)

Answer 18

Rapid melting of ice and snow following a volcanic eruption

Can be caused by tropical storms following an eruption

Typically flow down a valley side and occupy river channels

Speed of the mudflow can be affected by steepness of slope/gravity

Question 19

Outline the concept of mitigation in relation to the management of hazards

Answer 19

Mitigation is action to reduce the potential effects of a hazard

HMC includes mitigation as part of the pre-event action

This includes hazard mapping

Shows areas which are most vulnerable to a hazard

Question 20

What are love waves

Answer 20

A surface wave with horizontal displacement

Question 21

What are the four phases in the hazard management cycle

Answer 21

Mitigation
Preparedness
Response
Recovery

Question 22

What are the 4 phases in the hazard management cycle for?

Answer 22

Mitigation - aims to minimise the effect of future hazards

Preparedness - planning how to respond to a hazard

Response - how people/services react to a hazard

Recovery - Aims to get the affected area back to normal

Question 23

What are geophysical hazards

Answer 23

Caused by land processes such as earthquakes and volcanoes

Question 24

What are atmospheric hazards

Answer 24

Caused by climatic processes such as tropical storms and droughts

Question 25

What are hydrological hazards

Answer 25

Caused by water movement such as floods

Question 26

What are the theories of how tectonic plates move

Answer 26

Convection currents, ridge push and slab pull

Question 27

How do convection currents move tectonic plates

Answer 27

The core is very hot, lower parts of the asthenosphere heat up and slowly rise As they move to the top of the asthenosphere they cool down and become more dense and slowly sink The circular movement of the semi-molten rock create drag on the tectonic plates causing them to move

Question 28

How does ridge push move tectonic plates

Answer 28

Heat from rising convection currents, causes upwelling between two plates As new sea-floor cools it slides laterally down the slope due to gravity This pushes the plates aside by ridge push

Question 29

How does slab pull cause movement of tectonic plates

Answer 29

Pressure of plates moving as a result of ridge push forces 2 plates together Loss of heat from the lithosphere over time causes it to become cold and dense enough to have negative buoyancy This allows the plate to subduct under the less dense crust This drags the surface plates downwards by slab pull

Question 30

Describe sea floor spreading

Answer 30

As tectonic plates diverge, magma rises up to fill in the gap created this then cools to form new crust Overtime the new crust is dragged apart to form more new crust When this happens at a plate margin under the sea, the plate margin gets wider

Question 31

What are the three types of plate boundaries

Answer 31

Constructive Destructive Conservative

Question 32

On what type of plate boundaries do volcanoes form on

Answer 32

Constructive and destructive

Question 33

How do volcanoes form on constructive plate boundaries

Answer 33

When two plates are moving apart, the mantle is under pressure from the plates above When they move apart the pressure is released at the margin The release causes the mantle to melt producing magma, the less dense magma rises and erupts to form a volcano

Question 34

Example of constructive plate boundaries

Answer 34

Iceland Mid-Atlantic ridge African rift valley

Question 35

How is magma formed at constructive boundaries

Answer 35

Asthenosphere rises, pressure decreases towards crust so rock melts Plates moving apart creates a gap that relieves pressure