Hazards (introduction)

Question 1

What is a Hazard?

Answer 1

A hazard is the threat of substantial loss of life, substantial impact upon life or damage to property that may be caused by an event.

They can be natural events, events caused by human actions and natural events as a consequence of human actions-e.g.- wildfires caused by carelessness.

Question 2

What is a disaster?

Answer 2

A major hazard that causes wide spread destruction. Hazards should not be confused with natural disasters. A
disaster will only occur when a vulnerable population (one
that will be significantly disrupted and damaged) is exposed to a hazard.

Question 3

How is population expansion increasing Hazard risk?

Answer 3

1.Urbanisation-densely populated urban areas concentrate those at risk

2.poverty-expense of housing leads to building on risky ground.

Question 4

What factors influence the impact of Hazards?

Answer 4

1. location relative to areas of population
2. population
3. magnitude and extent
   4.wealth and capacity to cope

Question 5

What are the 3 types of geographical hazards?

Answer 5

1. Geophysical-driven from the Earths own internal energy sources. example-volcanoes

2.Hydrological-driven by water bodies, mainly oceans example, floods

3.Atmospheric-hazards caused by atmospheric processes and the conditions created because of these. example- wildfires

Question 6

Why are there different perceptions for hazards?

Answer 6

Hazard perception is the way in which someone understands or interprets a hazard. People have different viewpoints on how dangerous hazards are and what risk they pose. These perceptions are based on lifestyle factors such as economic and cultural elements.

1. Acceptance- (fatalistic tendencies) believing that hazards are a part of
   life and some believe its Gods will.

2.Domination-hazards are predictable, better understood by scientific research.

Question 7

How does wealth impact perceptions?

Answer 7

Wealthier people may perceive a hazard to be smaller as they are less vulnerable (e.g. they have the ability to evacuate with transport access, build stronger houses etc.). However some wealthy people may view hazards as more dangerous as there is a higher risk of financial loss and property damage then someone who is less wealthy.

Question 8

How does experience impact perceptions?

Answer 8

Someone who has seen first hand the impact of hazards is more likely to understand the full effects of hazards. Those who haven’t will not understand their full affect and may not treat them as seriously.

Question 9

How does religion and beliefs impact hazard perception?

Answer 9

Some people see Hazards as something sent from God for a reason and others may see them as a natural part of life, so they might not see hazards as negative. In contrast, those who believe in environmental conservation may see hazards as a threat to the natural environment especially as hazards are becoming more frequent due to global warming.

Question 10

How does education impact perception of hazards?

Answer 10

A person who is more educated about hazards will understand their full effect and know how devastating they are and have ben in the past. Those uneducated on hazards wont understand the full impacts and may not evacuate etc.

Question 11

What is the natural human response to Hazards?

Answer 11

The natural human response is to reduce the risk to life and equity.

Question 12

How can Hazards be responded to in a passive way?

Answer 12

Fatalism is an example of this. It is the belief that hazards are uncontrollable natural events and any losses because of them should be accepted as there is nothing we can do to stop them. Often held in low income countries.

Question 13

What are active responses to Hazards?

Answer 13

Often used in high income countries where governments invest in research, prediction, preparedness and mitigation.
Examples..
1. Prediction
2.Adaptation
3.mitigation

Question 14

What is adaptation?

Answer 14

Attempting to live with Hazards by adjusting lifestyle choices so that vulnerability to the hazard is lessened. e.g- earthquake -proof houses

Question 15

What is prediction?

Answer 15

Using scientific research and past events in order to know when a hazard will take place, so that warnings may be delivered and the impacts of hazards can be reduced.

Question 16

What is mitigation?

Answer 16

Strategies carried out to lessen the severity of hazards, for example, sandbags to offset the impact of flooding.

Question 17

What is management?

Answer 17

Coordinated strategies to reduce a hazards effects. This includes prediction, adaptation and mitigation.

Question 18

What is Risk sharing?

Answer 18

A form of community preparedness, whereby the community shares the risk posed by a natural hazard and invests collectively to mitigate the impacts of future hazards.

Question 19

What is ADAM

Answer 19

Automatic disaster analysis and mapping system, reduces response times as it is a database that pools information from the US geological survey and World bank and world food programme. This allows almost immediate access to information like the scale of the disaster, what supplies are available locally and established local infrastructure.

Question 20

What is the Hazard Management Cycle?

Answer 20

Highlights the attempts of governments, businesses and other stakeholders to reduce the losses from the Hazard and to provide rapid assistance to victims. For areas at risk it illustrates both pre- and post- event situations. The Hazard Management Cycle outlines the stages of responding to events, showing how the
same stages take place after every hazard.

Question 21

What does P.R.R.M mean on the hazard management cycle?

Answer 21

Preparedness= planning how to respond, large -scale events can rarely be prevented, but education and raising public awareness can minimise impact.

Response=Immediate action taken after the event (evacuation, rescue, medical assistance)

Recovery=long term responses, restoring the affected area to something approaching normality.(restoring services, reconstruction).

Mitigation=reducing the impact and severity of an event. (flood barriers, insurance, warning signals developed)

Question 22

How effective is the hazard management cycle?

Answer 22

-hazard models are useful but the lack of predictability of hazards makes the models less effective at accurately representing human responses to hazards.

• some hazards are complex and a more complex model is needed
• the model doesn’t include aspects of hazards such as the level of development.

-no timeframe - doesn’t accurately lay out the time taken for a full response and how that changes due to intensity.

-may not present hazards currently c / doesn’t take into account hazards that have been affected by climate change.

Question 23

How does the level of development impact responses?

Answer 23

Economic development will impact how a place can respond to a hazard. So a hazard of the same magnitude may have different effects in two places of contrasting development. Even if the hazard is identical, a less developed place will likely have less effective mitigation strategies as these are costly.

Question 24

What is the Park Model?

Answer 24

-A graphical representation of human responses to hazards.
-This describes three phases following a hazard event- relief , rehabilitation and reconstruction
-The model shows the steps carried out in the recovery after a hazard, giving a rough indication of time frame.
-The park model illustrates the changing quality of life through different phases of a disaster from stage 1 (pre-disaster) and stage 5 ( reconstruction).

Question 25

what is stage 1 of the park model?

Answer 25

Relief (hours/days)- the immediate local and global response in the form of aid, expertise and search & rescue -immediate appeal for foreign aid and the beginning of a global response

Question 26

What is stage 2 of the Park model?

Answer 26

-Rehabilitation(days-weeks)- infrastructure restoration ,temporary housing and services. Food and water distributed,

Question 27

What is stage 3 of the Park model?

Answer 27

-Reconstruction(weeks-years)- restoring to the same or better quality of life before the event took place. -Infrastructure is rebuilt -mitigation efforts for future events.

Question 28

What are the criticisms of the Park Model?

Answer 28

-It is generalised and does not consider levels of development or their considerations of hazard impact and recovery. HOWEVER, it does allow the trajectories of different events to be compared and highlights the significance of emergency relief and rehabilitation in the aftermath of natural hazards.

Question 29

What is the Earths shape?

Answer 29

-A Geoid , it is not perfectly sphere due to centrifugal forces.

Question 30

What is the Mantle?

Answer 30

-2900 km thick -mainly silicate rocks in a thick, liquid state due to the great heat and pressure -upper mantle is solid and sits on top of the asthenosphere, the lithosphere sits on top -density increases with depth into the lower mantle

Question 31

What is the asthenosphere?

Answer 31

-Semi molten layer constantly moves due to flows of heat called convection currents. -movements are powered from heat by the core -lithosphere is on top

Question 32

What is lithosphere?

Answer 32

-Rigid tectonic plates of crust and upper mantle -majority of the lithosphere is within the mantle -the top of the lithosphere is the crust which is the land we live on.

Question 33

What is the crust?

Answer 33

-5-10 km thick beneath oceans; up to 70 km thick beneath continents -the thin top of the lithosphere -consists of oceanic and continental crust

Question 34

What is the inner core?

Answer 34

-solid ball of iron/nickel -temperatures can reach 5000 degrees Celsius -1200 km thick -very hot due to pressure and radioactive decay, this heat is responsible for the Earth's internal energy and it spreads throughout.

Question 35

What is the outer core?

Answer 35

-2250 km thick -semi-liquid and mostly made up of iron

Question 36

What is Oceanic crust?

Answer 36

-A broken layer of basaltic rocks/ more dense then continental crust. Found beneath the worlds oceans,6 km thick and created through the movement of plates at constructive plate boundaries.

Question 37

What is Continental crust?

Answer 37

- mainly granitic rocks, older and less dense than oceanic crust, around 35km thick. Formed at subduction zones

Question 38

What is incidence?

Answer 38

-Every hazardous event varies in terms of its incidence, location and magnitude. These aspects of a natural event create different types of hazards and influence how people respond to these hazards. -Incidence is the frequency of a hazard. This is not affected by the strength of a hazard, it is just how often a hazard occurs. - Low incidence hazards may be harder to predict and have less management strategies put in place, meaning the hazard could be more catastrophic when it does eventually occur. -Low incidence hazards are usually more intense than high incidence hazards.

Question 39

What is Magnitude and intensity?

Answer 39

- Magnitude is the size of the hazard , this is usually how a hazards intensity is MEASURED -Intensity is the power of a hazard i.e. how strong it is and how damaging the effects are High magnitude, high intensity hazards will have the worse effects, meaning they will require more management. For example, more mitigation strategies will be needed to lessen the effects. Magnitude and intensity are NOT interchangeable terms. The magnitude is usually definable and can be a number- this does not change. Intensity however, is the effects on the person and can change dependent on the distance from the hazard or the management strategies used.

Question 40

What is distribution?

Answer 40

Where hazards occur geographically Areas of high hazard distribution are likely to have a lot of management strategies and those living there will be adapted to the hazardous landscape because it dominates the area more so than in places with low hazard distribution.

Question 41

What is the level of development?

Answer 41

-Economic development will affect how a place can respond to a hazard, so a hazard of the same magnitude may have very different effects in two places of contrasting levels of development -Even if the hazard is identical an area of lower development is less likely to have effective mitigation strategies, as these are costly. The effects of a hazardous event is likely to be much more catastrophic in a less economically developed area -However there are many high income countries that are not as prepared for natural hazards as they should be, meaning they lack management strategies for an event. This is especially true in multi-hazard environments where resources are spread thinly over a variety of hazards. -Overall, level of development may not have the biggest part to play in a hazard and it may have more to do with how these counties use their development for mitigation.

Question 42

Earths internal energy sources

Answer 42

Some of the earths internal energy may be primeval (retained by the ball of dust and gas from which the Earth evolved). But the greatest source of heat energy is derived directly from natural radioactive decay of uranium and other elements within the core.

Question 43

What are tectonic plates?

Answer 43

The lithosphere is broken up into large slabs of rock called tectonic plates the lithosphere is the rigid outer- most shell of our planet is broken up into tectonic plates.

Question 44

Who was Alfred Wegener?

Answer 44

He was a meteorologist born in 1880. He had the idea of continental drift which suggested that continents move around the Earth like giant rafts. He also proposed the theory that all the continents had originally been joined together but gradually moved apart over millions of years. His theories were updated by Harry Hess, an American geologist who made the theory of 'sea floor spreading'.

Question 45

What is the evidence for plate tectonic theory?

Answer 45

1. Shape of the continents- Wegener identified that South America and Africa appeared to 'fit together' like two jigsaw pieces 2.Geology-similar rock types on either side of the Atlantic Ocean. The Appalachian mountains in the USA are identical to the Scottish Highlands. 3.Fossils- Similar fossil types were found on the coasts of the continents. 4.Climatological evidence- Places as far as North America , Antarctica and the UK all contain coal deposits of a similar age that were formed in tropical conditions. They are no longer in tropical climate zones so must have drifted apart.

Question 46

why are plates moving-? 1. Convection Currents

Answer 46

Until recently, the dominant theory suggested that heat from the core was transferred to the Earths surface via large convection currents in the asthenosphere. The heated magma spreads out underneath the lithospheric plates and begin to cool, which causes them to be denser and sink downwards. However many scientists do not believe that convection explains the massive forces needed to move the plates. Instead two hypothesis have been suggested; ridge push and slab pull.

Question 47

2. Ridge push

Answer 47

Ridge push which can be more accurately named gravitational sliding, occurs at mid- Ocean ridges which are associated with constructive plate boundaries . The magma rises to the surface at mis ocean ridges and heats the surrounding rocks. These expand and become elevated above the sea floor, forming a slope, away from the mid- ocean ridge. As new rock is formed it cools and becomes denser. Gravity causes it to fall down the slope, away from the mid ocean ridge. Computer models have been used by scientists to show that this movement down the slope could drive plate movement.

Question 48

4. Palaeomagnetism

Answer 48

This tells us that new land gas been created due to patterns on the surface of the Earth.

Question 49

3. Slap pull

Answer 49

Slab pull has emerged as the more dominant theory over the last decade for explaining the movement of plates. At a destructive plate boundary, the subducting oceanic plate is denser then the surrounding material. As the plate begins to sink into the mantle, it pulls the rest of the plate behind it.

Question 50

5. Sea-floor spreading

Answer 50

This is where new Oceanic crust is formed through volcanic activity, causing the tectonic plates to move apart from each other. In the middle of the Atlantic Ocean, scientists found evidence from the age of the rocks either side of a split in the crust which proved that sea-floor spreading had happened. This is known as the Mid- Atlantic Ridge.

Question 51

What happens at constructive plate boundaries?

Answer 51

When two plates are moving apart they create a constructive plate boundary. Magma rises at the asthenosphere , as it cools it solidifies to form new dense basaltic rock.

Question 52

What are the landforms created at a constructive plate boundary?

Answer 52

-In the oceans, this produces mid-ocean ridge systems such as the mid- Atlantic ridge where the North American and Eurasian plates are moving away from each other. -In continental areas, stretching and collapsing of crust creates rift valleys such as the East African rift valley. -Shield volcanoes are also formed when magma rises to the surface as plates move apart, example is Katla in Iceland.

Question 53

What happens at Destructive plate boundaries?

Answer 53

When two plates collide they form a destructive plate margin. 1.when an Oceanic plate meets a Continental plate the denser oceanic plate subducts the continental one. The plate subducting leaves a deep ocean trench .Fold mountains occur when sediment is pushed upwards during subduction. The extra magma created causes pressure to build up. Pressurised magma forces through weak areas in the continental plate. Explosive, high pressure volcanoes erupt through the continental plate, known as composite volcanoes. 2.Oceanic and Oceanic- the heavier plate subducts, leaving an Ocean trench. Fold mountains will also occur. Built up pressure causes underwater volcanoes bursting through oceanic plate. Lava cools and creates new land called island arcs. 3. Continental and Continental- Both plates are not as dense as oceanic so lots of pressure builds. There is no subduction of continental crust. Pile up of continental crust on top of lithosphere due to pressure between plates. Fold mountains formed from piles of continental crust.

Question 54

What are the examples of Landforms formed at destructive plate boundaries?

Answer 54

-The Himalayas are an example of a fold mountain formed when continental meets continental -Nazca plate (oceanic) subducts South American Plate (continental) forms the Atacama sea trench. -Examples of Island Arcs include the Japanese Islands. Formed when oceanic meets oceanic.

Question 55

What happens at conservative Plate Margins?

Answer 55

Here, the plates rub past each other, either in opposite directions or in the same direction at different speeds. No plates are destroyed so no landforms are created. When these plates slide past each other, friction occurs which leads to building stress when sticking occurs. This is released in shockwaves as an Earthquakes. Example- The San Andreas Fault, which marks the junction between the North American and Pacific Plates.

Question 56

What are Magma Plumes?

Answer 56

Upwelling of abnormally hot rock within the mantle, they can form island arcs through hotspot activity. The plate passes over the magma plume and weaknesses in the crust allow it to escape onto the surface as an active volcano. The country of Iceland's formation is explained by a magma plume. The plume stays in the same place but the plates continue to move, which sometimes causes a chain of islands (such as Hawaii).

Question 57

What are hotspots?

Answer 57

A volcanic hotspot is an area in the mantle from which heat rises as a thermal plume from deep in the Earth. High heat and low pressure at the base of the lithosphere facilitates the melting of rock. This melting of rock is magma and it rises through cracks and erupts to form volcanoes.

Question 58

What is the distribution of hotspots like?

Answer 58

There is no specific pattern , no association with plate margins. Examples include Siberian traps, Iceland, Canary Islands and the Galapagos islands.