HAZARDS

Question 1

what are the different typles of hazard?

Answer 1

• tectonic- e.g. Volcanoes
• geological- e.g. landslides
• atmospheric- e.g. tropical storms
• hydrological- e.g. tsunamis
• biological- e.g. wildfires

Question 2

what are human hazards?

Answer 2

• explosions
• chemical release
• nuclear incidents

Question 3

what are natural hazards?

Answer 3

• earthquakes
• volcanoes
• landslides
• storms
• wildfires
• floods

Question 4

what is the difference between a natural event and a natural hazard?

Answer 4

For a natural event to become a hazard it has to involve people

Question 5

what is Dreggs model?

Answer 5

shows how the the impact of a natuaral hazard is influenced by both hazard magnitude and the countries level of development. LICs are most effected by low magnitude hazards and HICs by high magnitude hazards.

Low-magnitude hazards
* LICs have weak infrastructure, poor building quality and limited warning systems
→ high deaths and damage

• HICs: can cope better
  → low impact

High-magnitude hazards
HICs: lots of high-value infrastructure and dense cities
→ huge economic losses

LICs: fewer valuable assets
→ lower total economic cost

Question 6

whats a Disaster?

Answer 6

a natural or human event that causes serious disruption to a community resulting in widespread social, environmental or economic losses that exceed the ability of the affected population to cope using its own resources

definition

Question 7

what is a hazard?

definition

Answer 7

A human or natural event that could potentially affect human life, property of activity.

Question 8

give an example of areas most vunerable to hazards?

Answer 8

an area prone to hazards that has a high populations such as favalas (slums) in bangledesh , bangledesh is built on a delta so is really low lying and prone to flooding and cyclones

Question 9

what is risk?

Answer 9

the exposure of people to hazourdous events

Question 10

why do people consciously put themselves at risk by living in hazourdous areas?

Answer 10

Due to social, political, economic and cultural facctors people may not be able to move from one place to another and give up there homes and jobs. Also Hazourdous events are unpredictable and you cant always predicts the frequency, magnitude or scale of an event, especially in poorer countries.

Question 11

why is risk of Hazardous events increasing in some countries?

Answer 11

• frequency increasing due tii climate change
• vunerablilty increaing due to unsustainable development leading to poor land use and environmental degradation
• due to poverty and urbanisation coping capasity is decreasing
• percepttion oor ignorance of the hazard that its not bad
• changing risk as some areas that werent, nnow are at risk

Question 12

how is risk different in developed countries?

Answer 12

Risk is lower in more developed countries due to improving prediction systems, and the resources and technology to adapt

Question 13

How does a hazard become a disaster?

Answer 13

1. vunerability due to poverty or failling political, social and environmental systems
2. pressures like lack of education, rapid population and urbanisation increase, over-exploitation of resourses
3. unsafe population condition- poverty, famine and disease, lack of preparedness, unprotected buildings

Question 14

Describe the vunerability quadrant?

Answer 14

Question 15

What are factors that increase vunerablility?

Answer 15

• population growth
• urbanisation and urban sprawl
• environmental degration
• ageing population
• old infastructure
• overreliance on power, water and communication systems

Question 16

what are factors that reduce vunerability?

Answer 16

• warning and emergency responce systems
• economic wealth
• government disaster assistance programs
• insurance
• community education
• hazard engeneering and infastructure

Question 17

what are reasons recorded hazards have increased?

Answer 17

• climate change- leading to increased frequency of hazards
• increasing population- turning many natural events into hazards
• improved detection methods

Question 18

what are factors influencing the perception of natural hazards?

Answer 18

• socio-economic status- rich cope better but have more to lose
• level of education
• employment status- could lose job
• religion and cultural background- trust god and not act themselves
• family situation- may have people to care for
• past experience
• personality and values- persevere or give up

Question 19

define adaptation

Answer 19

process of adjusting to the hazard and living with it to reduce harm or exploit opportunities

Question 20

define fatalism

Answer 20

the viewpoint that natural hazards are uncontrollable, inevitable events, leading communities to passively accept risks rather than taking action to prevent or mitigate them

Question 21

what is the Park Model?

Answer 21

Question 22

according to the park model, what are the three stages that follow a Hazard event?

Answer 22

• relief - the immediate responce, including search and rescue, provision of emergency medical assistance and aid
• rehabilitation - a longer phase that includes temporary restoration of services and infastructure such as temporary schools and shelters
• reconstruction - permenant restoration which aims to provide the same or improved quality of life e.g. through the rebuilding of infastructure that is reinforced to be resistant to the hazard

Question 23

what does the park model show?

Answer 23

how a countries quality of life changes overtime before during and after a hazard event and is mainly used to compare responces in HICs and LICs.
LICs normally show a steeper drop due to more deaths, infastructure collapse and limited emergency respone, and a slower recovery.
HICs have a smaller drop due to better building design, emergency services and insurance, and a faster recovery.

Question 24

what is the hazard management cycle?

Answer 24

* a continuous loop showing the approach to managing a hazard * includes 4 stages- hazard occurs then, responce, recovery, mitigation and preparedness.

Question 25

what happens in each stage of the hazard management cycle?

Answer 25

* preparedness- using evidence and dta from past events to plan fro associated hazards. to minimise the impact on the population * responce- deploying services and resources to save people and property from harm e.g. fire and rescue services after earthquakes * recovery- concerned with post disaster reconstruction and restoration of the local built and natural environment * mitigation- steps taken to minimise negative impacts associated with the hazard e.g. earthquake proof buildings

Question 26

what are the three main types of rock?

Answer 26

* igneous rock (hardest) * sedimentary (softest) * metamorphic

Question 27

explain the theory of continential drift

Answer 27

* Alfred Wegener published a controversial theory that the Earths continents had once been part of a single landmass - Pangea * he believed thaat the plates had gadually drifted apart over millions of years, but he didnt know how or why

Question 28

what is tectonic plate movement? | what is the asthenosphere?

Answer 28

tectonic plates move slowly through the asthenoshere, the asthenosphere is a weak, flowable layer of the upper mantle and is just below the lithoshere (crust and uppermost mantle)

Question 29

what are the different theories of what causes techtonic plates to move?

Answer 29

* convection currents * slab push and ridge pull

Question 30

what are convection currents and the theory behind it?

Answer 30

movement in the mantle caused by rising and falling mantle (like the global circulation model * heat from radioactive decay in the core heats the mantle and causes it to rise * they rise through the mantle to the asthenosphere cooling and spreading out before sinking back down * as they reach the asthenosphere they carry/ move the lithosphere plates above them

Question 31

what is slab push?

Answer 31

* a subduction zone is formed when two plates move towards each other * the heavier and denser Oceanic plate subducts under the lighter, less dense continental plate * as the plate sinks, gravity pulls the plate down into the mantle (known as slab pull)

Question 32

wha is ridge pull?

Answer 32

* new oceanic crust is fromed at mid-ocean ridges at a constructive plate boundary as the plates move apart * as the crust moves away from the mid-ocean ridge it cools and becomes thickr and denser * this causes the lithospher to slope pushing it forward (know as ridge push)

Question 33

what are the four main layers of the Earth?

Answer 33

* the crust * the mantle * the outer core * the inner core

Question 34

what are the two different types of crust?

Answer 34

* continential crust- a thicker (up to 70km), less dense layer * Oceanic- a thinner (5-10km), dense layer

Question 35

describe the core layer of the Earth

Answer 35

made up of two parts: * inner core- solid centre, mostly coposed of iron * outter core- semi-molten, mostly liquid iron and nickle * the core is the hottest part of the Earth and its heat is the main driver of tectonic activity * the heat is caused by radioactive decay of elements like uranium in the core

Question 36

what are the layers of the Earth?

Answer 36

Question 37

describe the lithosphere

Answer 37

* consists of serveral major and several minor tectonic plates which float on top of the asthenosphere * divided into two types: oceanic plates and continential plates

Question 38

what is palaeomagnatism?

Answer 38

the study of the Earths magnetic field preserved in rocks, as magma cools at constructive plate margins, iron minerals align with the magnetic field, creating magnetic stripes as the Earths magnetic north and south poles flip every 500,000 years **magnetic reversals** palaeomagnetism helped verifyAlfred Wegemers theory of continental drift

Question 39

what does palaeomagnetism provide evidence for?

Answer 39

provides evidence for **sea floor spreading** as magnite (iron oxide) in lava is erupted ontop the sea floor cools and solidfies the iron oxide lines up with the magnetic fields, recording the magnetic orientation, which flips every 500,000 years, and either side of the plate margins the direction of minerals is a mirror images

Question 40

what are the four main tectonic plate boundaries?

Answer 40

* constructive * conservative * destructive collision * desructive subductive

Question 41

describe constructive plate boundaries

Answer 41

* plates move apart * volcanos and eathquakes can occur at this boundary * create two different landforms- ocean ridges and rift valleys

Question 42

how is an Ocean ridge formed?

Answer 42

* at a constructive (diverging) boundary under the ocean * as the plates move appart the magma rises up to fill the gap, and over time it accumulates becoming wider and taller * an example of an ocean ridge is the Mid Atlantic Ridge

Question 43

how is a rift valley formed?

Answer 43

* at a constructive plate boundary when diverging plates are beneath the land * as the plates move apart the crust stretches and fractures * areas of crust drop down between faults to create a valley * an example is the east african rift valley

Question 44

what is sea floor spreading?

Answer 44

* the process occuring at an oceanic constructive plate boundary at aan ocean ridge where the tectonic plates move apart allowing magma to rise and form new crust * proved as the youngest rocks were at in the middle of the ocean and paleomagnetism

Question 45

whats happens at destructive plate boundaries?

Answer 45

plates move towards each other, can be desructive collions or destructive subductive

Question 46

describe a destructive subductive plate boundary

Answer 46

* when an oceanic plate and a continental plate meet * the denser heavier oceanic plate subducts under the lighter less dense continental plate- forming a deep ocean trench in the subduction zone * forms deep ocean trenches and fold mountains * the zone of earthquakes along the slab is known as the benioff zone * violent volcanos (composite) and earthquakes and eruptions happen at this plate boundary

Question 47

what is the Benioff zone?

Answer 47

when two plates converge and one is subducted under the other and is destroyed in the mantle, the zone where subduction occurs is called the Benioff zone

Question 48

how are fold mountains formed?

Answer 48

* at destructive plate boundaries * as the plates collide the rock layers are compressed and forced to buckle upwardsinto large mountain ranges (typically formed from sedimentary rock layers that were deposited at the bottom of oceans * takes thousands to millions of years for the mountain to fully form * examples are the Andes, Alps or the Himalayas

Question 49

how are deep ocean trenches formed?

Answer 49

* at a destructive subductive plate boundary * the oceanic plate bends and subducts forming ocean trenches adjacent to land areas

Question 50

describe what happens at a destructive collision boundary

Answer 50

* two continential plates move towards each other * neither is dense enough to subduct so the land is pushed upwards * this forms fold mountains such as the Himalayas * no volcanic activity as there is no subduction

Question 51

describe the formation of fold mountains at a destructive subductive boundary

Answer 51

* the oceanic plate is subducted under the continential plate * the collision creates compressional forces and the sedimentary rock layers are compressed, folded and thickened * continued compression over millions of years forces the folder rock upwards forming fold mountains. * often also has deep ocean trenches, volcanoes and earthquakes

Question 52

describe what happens at a conservative plate boundary

Answer 52

* plates move past each other in different directions or the same directions at different speeds * earthquakes are the only hazard at this boundary * plates can stick causing significant pressure build up which suddenly can jolt and release as an earthquake

Question 53

what are hot spots?

Answer 53

* hot spots form around the core of the earth where radioactive decay is concentrated * this extreme heat causes magma plumes which are upwellings of superheated rock that rise from deep within the earths mantle towards the surface * they can break through the middle of a tectonic plate and cause volcanic activity and earthquakes away from plate boundaries

Question 54

what do hotspots/ magma plumes form?

Answer 54

* magma plumes can break through tectonic plates and lead to volcanoes and earthquakes * they can lead to the formation of island chains

Question 55

how do island chains form?

Answer 55

* formed by hotspots/ magma plume breaking though the surface of a tectonic plate and leading to the formation of hotspot volcanoes which can create islands from eruptions * magma plume is stationart so when tectonic plates move over it a chain of volcanoes are formed * creating island chains like Hawaii * the volcanoes are active when they are above the magma plume but not once theyve moved off it