GCSE geography - natural hazards (chapters 1, 2, 3, 4)

studied byStudied by 10 people
0.0(0)
get a hint
hint

natural hazard

1 / 215

Tags and Description

216 Terms

1

natural hazard

a natural event which has the potential to threaten both life and property

New cards
2

natural disaster

a natural hazard that has actually happened

New cards
3

what are 7 examples of natural hazards?

earthquakes, volcanic eruptions, tsunamis, floods, droughts, landslides, storms

New cards
4

what are 3 types of storms?

tornado, snow, lightning

New cards
5

what are 3 examples of tropical storms?

hurricanes, cyclones, typhoons

New cards
6

how are natural disasters categorised?

are they geological (tectonic + geomorphological) or meteorological?

New cards
7

what is a meteorological natural disaster?

caused by weather conditions. this can be either over a short or long period of time. can affect a small or large area.

New cards
8

what is a tectonic natural disaster?

caused by the movement of the earth’s tectonic plates

New cards
9

what is a geomorphological natural disaster?

to do with the movement on top of the earth’s surface

New cards
10

hazard risk

the chance or probability of being affected by a natural disaster

New cards
11

what are the 8 main hazard risk factors?

education, frequency, geographical location, level of development/wealth, magnitude, natural factors, population density and distribution, time

New cards
12

why is education a hazard risk factor?

won’t stop a natural disaster from occurring but may reduce impacts and allow more people to survive

New cards
13

why is frequency a hazard risk factor?

how often a natural disaster occurs

New cards
14

why is geographical location a hazard risk factor?

the position of a country or region in the world

New cards
15

why is level of development/wealth a hazard risk factor?

allows richer countries (MEDCs) to respond quickly and effectively to natural disasters faster then in poorer countries (LEDCs)

New cards
16

why is magnitude a hazard risk factor?

the size of the event

New cards
17

why are natural factors hazard risk factors?

elements such as geology, topography and relief can affect the risk and severity of natural disasters

New cards
18

why is population density and distribution a hazard risk factor?

the number of people living in a place and the spread of people in an area or country

New cards
19

why is time a hazard risk factor?

very influential e.g. if its day or night

New cards
20

what are some more hazard risk factors?

distance from epicentre, depth of epicentre, location of fault lines

New cards
21

what are the four layers of the earth?

crust, mantle, outer core, inner core

New cards
22

what is the continental drift theory?

the theory that all the continents on the earth were once joined, forming one large continent called Pangea. This theory was developed by Alfred Wegener in 1912.

New cards
23

continental drift theory explanation

over 180 million years ago, Pangea separated and broke into separate continents.

New cards
24

continental drift theory evidence (2)

  • the different continent borders and coastlines all fit together (e.g. east coast of south america and west coast of africa)

  • ores on the matching coastlines are the same

New cards
25

what is the earth’s crust divided into?

slabs called tectonic plates

New cards
26

what are these plates made of?

two types of crust- continental and oceanic

New cards
27

how thick is oceanic crust?

5-10km thick

New cards
28

how old is oceanic crust?

180 million years old

New cards
29

does oceanic crust sink?

yes

New cards
30

what is oceanic crust made up of?

basalt

New cards
31

is new crust formed with oceanic crust?

yes, at constructive plate margin

New cards
32

is crust destroyed with oceanic crust?

yes, at destructive plate margin

New cards
33

how thick is continental crust?

25-100km thick

New cards
34

how old is continental crust?

3.4 billion years old

New cards
35

is oceanic or continental crust more dense?

oceanic, so will result in subduction

New cards
36

does continental crust sink?

no

New cards
37

what is continental crust made up of?

granite

New cards
38

is new continental crust formed?

no

New cards
39

is continental crust destroyed?

no

New cards
40
<p>what is this?</p>

what is this?

destructive/convergent plate margin

New cards
41

what will destructive/convergent plate margins result in?

earthquake / volcanic eruption

New cards
42
<p>what is this?</p>

what is this?

constructive/divergent plate margin

New cards
43

what will constructive/divergent plate margin result in?

earthquake / volcanic eruption

New cards
44
<p>what is this?</p>

what is this?

conservative/transform plate margin

New cards
45

what will conservative/transform plate margin result in?

earthquakes

New cards
46
<p>explain why volcanoes occur at destructive plate boundaries (6 marks)</p>

explain why volcanoes occur at destructive plate boundaries (6 marks)

  1. an oceanic plate (Nazca) is pushing towards a continental plate (south american)

  2. oceanic plate is subducted beneath continental plate because it’s denser

  3. the plate is destroyed in the mantle due to increased heat

  4. continuous movement causes a build-up of friction and pressure

  5. lava is forced into molten rock due to pressure, through the weakest point of the earth’s crust

  6. this is repeated until lava cools and solidifies to become a composite cone volcano

  7. if there is a volcanic eruption, it will be highly explosive, but they erupt less frequently than other volcanoes

  8. it will be highly explosive due to a build up of carbon from the seabed, and a build up of pressure and friction

New cards
47
<p>what volcano is this</p>

what volcano is this

shield volcano

New cards
48
<p>what volcano is this</p>

what volcano is this

cone volcano

New cards
49
<p>what is a convergent collision/how are fold mountains formed?</p>

what is a convergent collision/how are fold mountains formed?

where two continental plates push into each other, or collide (where they are the same density), and create fold mountains

New cards
50

what is an example of a convergent collision?

the Indoaustralian and euarasian plate = the himalayas

New cards
51

what happens at a constructive/divergent plate boundary? (4 points)

  1. the tectonic plates are moving apart from eachother due to convection currents in the mantle

  2. a gap is formed and immediately filled by magma rising from the mantle

  3. this magma cools and solidifies to form rock or new volcanic crust

  4. this repeats until many layers of magma build up to form wide, low volcanoes called shield volcanoes

New cards
52

how are fault lines formed on constructive/divergent plate boundaries?

  1. the plates can get stuck as they move apart, building stress

  2. this can cause big cracks (faults) to be created on the moving plates

New cards
53

what is an example of a constructive/ divergent plate boundary which has formed a shield volcano?

north american and eurasian plates = Mid Atlantic Ridge

New cards
54

what happens at conservative/ transform plate boundaries? (4 points)

  1. tectonic plates (in a slip fault) slide against each other either moving in the same or opposite direction (as a result of convection currents)

  2. this creates friction which builds up in the focus spot

  3. this friction is released in the form of seismic waves into the earth’s crust after a sudden slip

  4. these seismic waves trigger earthquakes

New cards
55

when will the magnitude of the earthquake increase/decrease?

they will decrease as they cover more distance, so the further down in the earth the focus point is, the smaller the magnitude

New cards
56

how are conservative/tranform plates different from constructive and destructive plates? (2 points)

  1. no volcanoes are involved

  2. no crust is destroyed or created

New cards
57

where are composite volcanoes found and why?

destructive plate boundaries, because when the plates collide, the denser plate is subducted, magma replaces it etc …

New cards
58

where are shield volcanoes found and why?

constructive plate boundaries, because the plates diverge, new crust emerges etc …

New cards
59

do composite or shield volcanoes erupt more frequently?

shield volcano

New cards
60

do composite or shield volcanoes have more ‘vicious’ eruptions?

composite volcano

New cards
61

why do composite volcanoes erupt less frequently?

high viscosity lava traps bubbles of lava, so it’s more eruptive, and pressure needs to build up for this

New cards
62

composite volcano lava type? (3)

  • volcanic gases rarely emerge

  • flows for short distances

  • viscous (thick + sticky lava)

New cards
63

shield volcano lava type? (3)

  • volcanic gases stay in lava

  • flows for long distances

  • not viscous (hot + runny lava)

New cards
64

examples of composite volcanoes? (2)

  • Krakatoa (Indonesia)

  • Mount St Helens (USA)

New cards
65

examples of shield volcanoes? (2)

  • Mauna Lao (Hawaii)

  • Heimay (Iceland)

New cards
66

what are 5 primary hazards caused by volcanic eruptions?

  1. Ash falls

  2. Gas clouds

  3. lava flows

  4. pyroclastic flows

  5. volcanic bombs

New cards
67

what are ash falls?

small erupted material which can travel long distances

New cards
68

what are gas clouds?

toxic clouds which can suffocate people e.g. CO2, hydrogen sulfide, sulphur dioxide

New cards
69

what are lava flows?

streams of molten rock which slow as they cool

New cards
70

what are pyroclastic flows?

very hot flows of gas and ash, up to speeds of 700km/h

New cards
71

what are volcanic bombs?

solid lumps of lava which fly through the air (can be as big as a house)

New cards
72

what are 5 secondary hazards of volcanic eruptions?

  1. lahars

  2. tsunamis

  3. climate change

  4. landslides

  5. glacier bursts

New cards
73

what are lahars/ how are they caused by volcanic eruptions?

volcanic mud flows which travel along river valleys

New cards
74

what are tsunamis/ how are they caused by volcanic eruptions?

giant sea waves generated by underwater volcanoes

New cards
75

what is climate change/ how is it caused by volcanic eruptions?

volcanoes send ash into the atmosphere, reflecting radiation from the sun back into space, causing heating

New cards
76

what are landslides/ how are they caused by volcanic eruptions?

rock and earth which tumble down a slope, triggered by tectonic activity

New cards
77

what are glacier bursts/ how are they caused by volcanic eruptions?

large floods caused by the melting of ice beneath a glacier

New cards
78

what are 3 primary/ immediate effects and impacts of volcanic eruptions?

  1. many people killed/injured

  2. farmland + buildings destroyed

  3. communications damaged/disrupted (e.g. transport, water, electricity)

New cards
79

what are 5 secondary/ long term effects of volcanic eruptions?

  1. spread of disease due to no clean water/ broken sewers

  2. hospitals are overwhelmed

  3. shortage of necessities (e.g food, water, shelter, medicine)

  4. local businesses have reduced income + food production

  5. economic impact from cost of rebuilding + air travel disruption

New cards
80

how can we react to volcanic eruptions? (3 points)

  1. set up exclusion (safe) zones

  2. build volcano observatories

  3. rebuild buildings + economy

New cards
81

how can we measure earthquakes? (2)

  1. richter scale (measures magnitude/energy of earthquakes)

  2. mercalli scale (measures intensity/damage caused by earthquakes, 1-12 levels)

New cards
82

what is the richter scale?

a logarithmic scale (each 1.0 is 10x bigger, e.g 6.0 is 10x bigger than 5.0)

New cards
83

is the richter or mercalli scale more accurate?

richter, because with mercalli, the results can change, and it’s subjective

New cards
84

why do some people continue to live in areas at risk from tectonic hazards? (4)

  1. well developed settlements would struggle to relocate

  2. jobs/families in endangered areas

  3. tourism creates jobs and opportunities in endangered areas (e.g. Blue Lagoon in Iceland)

  4. land is fertile so opportunity for farmers

New cards
85

what is a LIC tectonic hazard?

Nepal (Ghorka) Earthquake

New cards
86

basic facts about the Ghorka earthquake? (4)

  • 7.8 magnitude

  • 8km deep focus point

  • on a convergent collision plate boundary

  • in April 2015

New cards
87

primary impacts of ghorka earthquake (4)

  • 9000 dead (approx)

  • 19000 injured

  • hundreds of thousands homeless

  • triggered an avalanche on the himalayas(20 dead)

New cards
88

secondary impacts of ghorka earthquake (3)

  • tourism rates dropped, $7 billion loss, main source of income

  • 600,000 buildings destroyed

  • crops damaged, loss that harvest season

New cards
89

immediate responses to ghorka earthquake (2)

  • $1 million+ aid pledged from India + China

  • 100+ search + rescue teams provided by the UK

New cards
90

long term responses to ghorka earthquake (1)

  • aid donated by many countries

New cards
91

what is a HIC earthquake case study?

New Zealand

New cards
92

basic facts about new zealand earthquake (4)

  • february 2011

  • 12.51pm

  • 5km deep focus point

  • 6.3 magnitude

New cards
93

primary impacts of new zealand earthquake? (3)

  • 185 dead

  • approx 2000 injured

  • 10,000 houses needed to be rebuilt

New cards
94

secondary impacts of new zealand earthquake? (2)

  • liquefaction occurred, land cannot be rebuilt on

  • infrastructure severely damaged (roads, bridges etc)

New cards
95

immediate responses to new zealand earthquake (3)

  • search + rescue teams came globally

  • temporary housing provided

  • pop up hospitals

New cards
96

long term responses to new zealand earthquake (2)

  • unstable buildings were demolished

  • infrastructure was rebuilt

New cards
97

what is liquefaction?

when the ground shakes and causes water + mud to rise to the surface

New cards
98

what part of the earth is the sun concentrated at?

the equator

New cards
99

what part of the earth is the suns rays more spread out?

the polar regions

New cards
100

cold air …

sinks

New cards

Explore top notes

note Note
studied byStudied by 1 person
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 4 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 12 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 23 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 39 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 82 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 4 people
Updated ... ago
5.0 Stars(1)
note Note
studied byStudied by 120 people
Updated ... ago
5.0 Stars(1)

Explore top flashcards

flashcards Flashcard56 terms
studied byStudied by 13 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard60 terms
studied byStudied by 3 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard89 terms
studied byStudied by 3 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard25 terms
studied byStudied by 129 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard43 terms
studied byStudied by 26 people
Updated ... ago
5.0 Stars(2)
flashcards Flashcard29 terms
studied byStudied by 9 people
Updated ... ago
5.0 Stars(1)
flashcards Flashcard60 terms
studied byStudied by 109 people
Updated ... ago
5.0 Stars(3)
flashcards Flashcard93 terms
studied byStudied by 161 people
Updated ... ago
4.6 Stars(8)