Tectonic Hazards Flashcards
1
Q
what is the distribution of earthquakes like? (for all three types of focus)
A
- on plate bounderies (shallow focus)
- lots of intermediate focus earthquakes on the west coast of south america
- deep focus earthquakes in south america and asia
2
Q
whats the distribution of volcanoes like?
A
- lots of volcanic activity on the west coast of north and south america
- lots on the north east coast of oceania
- lots on the south east coast of asia
3
Q
whats the distribution of tsunamis like?
A
- most highly destructive (around 5m) are in New Zealand, south east Asia and North/South America.
- most moderate (around 2m) are located on the south west coast of Australia along with some under 2m.
- some moderate ones found on the east coast of Africa
4
Q
how thick is the different parts (oceanic and continental) of the crust on earth?
A
oceanic- 7km thick
continental- up to 70km thick
5
Q
how deep is the mantle?
A
700km to 2890km deep
6
Q
how deep is the outer core?
A
2890km to 5150km deep
7
Q
how deep is the inner core?
A
5150km to centre
8
Q
whats the temperature of the crust?
A
surface temp to about 400*c
9
Q
whats the temperature of the mantle?
A
870*c
10
Q
whats the temperature of the outer core?
A
4400c to 6100c
11
Q
whats the temperature of the inner core?
A
7000*c (radioactive decay)
12
Q
how dense is the crust?
A
less dense:
oceanic- 2.7g/cm^3
continental- 3.3g/cm^3
13
Q
how dense is the mantle?
A
less dense to medium density
14
Q
how dense is the outer core?
A
dense
15
Q
how dense is the inner core?
A
very dense
16
Q
what is the composition of the crust?
A
granite (continental) and basalt (oceanic)
17
Q
what is the composition of the mantle?
A
peridote upper = olivine
lower = magnesium silicate
18
Q
whats the composition of the outer core?
A
12% sulphur
88% iron
19
Q
whats the composition of the inner core?
A
20% nickel
80% iron
20
Q
whats the physical state of the crust?
A
solid
21
Q
whats the physical state of the mantle?
A
phases of liquid and solid in layers
22
Q
whats the physical state of the outer core?
A
liquid (generate magnetic field)
23
Q
whats the physical state of the inner core?
A
solid (generates heat)
24
Q
what happens at a constructive plate boundary?
A
they move apart
25
what happens at a transform (conservative) plate boundary
they slide past eachother
26
does
- seismic activity
- volcanic activity
occur at a constructive plate boundary?
- Yes (shallow focus + low magnitude)
- Yes (effusive flowing eruptions + low VEI)
27
what are the features of a constructive plate bounderies (what forms)?
island arc, oceanic trench
28
does
- seismic activity
- volcanic activity
occur at a destructive (ocean and continent) plate boundary?
- Yes (range of focal depths from shallow to 700km, along benioff zone, often high magnitude 6-8)
- Yes (explosive, moderate to high 5-6 VIE)
29
what are the features of a destructive plate boundary (ocean and continent)?
fault lines, ridges and surface scarring
30
what forms at a destructive ocean and ocean plate boundary? (seismic activity and volcanic is the same as o and c)
oceanic trench, fold mountains, volcanic peak
31
does
- seismic activity
- volcanic activity
occur at a collision plate boundary?
- Yes (shallow focus, moderate magnitude 6-8)
- No (usually none, occasional fissure eruptions)
32
what features are at a collision plate boundary?
- fold mountains, plateus
33
does
- seismic activity
- volcanic activity
occur at a transform plate boundary?
- Yes (moderate to high magnitude earthquakes of shallow focus)
- Yes/No (usually none, occasional fissure eruptions)
34
what features are shown at a transform plate boundary?
fault line (eg. San Andreas Fault)
35
what is slab pull?
- older colder plates sink at subduction zones (because as they cool, they become more dense than the underlying mantle)
- the cooler sinking plate pulls the rest of the warmer plate along behind it
36
what is paleomagnetism?
- discoveries were made that oceanic crust showed symmetrical bonds of magnetic stripes, formed either side of mid ocean ridge
- the earths magnetic field reverses approximately every 200,000 to 300,000 years.
- this helped to show that new oceanic crust was formed and helped to date rocks.
37
what did paleomagnetism prove?
sea floor spreading is a key role in plate boundary movement
38
whats the most convincing evidence of the theory of plate boundary’s constantly moving?
tectonic hazards (earthquakes, volcanic activity, mountain building along plate boundaries)
39
name an example of a collision plate boundary formation?
Himalayan Mountain Range
40
name an example of a constructive plate boundary formation?
Mid Atlantic Ridge- Iceland
41
name an example of a transform plate boundary formation?
San Andreas Fault
42
what hazards follow a:
-destructive
-collision
-constructive
-transform
- volcano, tsunami, earthquake
- earthquake
- tsunami, volcano, earthquake
- earthquake
43
examine why volcanoes aren’t created at all plate boundaries?
no way for magma to rise at a transform boundary
44
does all tectonic activity occur on plate boundaries?
no, because a few volcanoes are in the middle of the pacific ocean, which is very far from the plate boundaries. Also, many earthquakes are in central Asia, again not near a boundary.
45
discuss whether you think intra-plate activity can be more or less destructive than activity on plate boundaries?
interplate-
• occurs at plate boundery
• more common
• recognised on the surface
• releases stress but dissipated quickly.
Intraplate -
• not at plate boundary
• less common
• rarely recognised
• release more stresss-dissipates slower
46
how does focus depth influence the strength of an earthquake?
if a focus is shallow, the strength of an earthquake will be higher because the energy has less distance to travel
47
how does type of boundary influence the strength of a earthquake?
destructive has the most severe earthquake if its a destructive plate boundary - stronger.
48
how does distance from epicentre affect the strength of an earthquake?
further from the epicentre is weaker
49
how does geology influence the strength of an earthquake ?
if the rocks are weaker the energy will dissipate quicker so its a weaker earthquake
(geological fault lines or intraplate)
50
what is amplitude?
maximum extent of a vibration, measured from position of equilibrium
51
describe primary waves
- body wave
- highest velocity
- least damaging
- reaches surface first
- travel through solids, liquids, shaking back and forth
52
describe secondary waves
- body wave
- slower velocity
- higher amplitude
- move slower
- only through solid
- sideways motion
- more damaging than p
53
describe love waves
- surface waves
- highest amplitude
- move slowest
- most damaging
- shake ground side to side
- larger
- focus all energy on Earths surface
54
how are tsunamis formed?
• earthquake changes shape of sea floor causing displacement of water
• large waves form and move at up to 800km/h
• waves slow in shallower coastal areas but increase in height
55
name the 6 hazards of a volcano
- lava flows
- pyroclastic flows
- tephra
- gas eruptions
- lahars
- jokulhlaup
56
location of the boxing day earthquake/tsunami 2004
• indian ocean
• epicentre just off the coast of sumatra, indonisia
• affected thailand, sri lanka, malaysia and india
• caused by indo-australian plate and subducting under eurasian plate
57
what type of hazard is a tsunami?
secondary
58
causes of the boxing day tsunami?
• underwater 9.0 magnitude earthquake
• indo-australian plate subducted under eurasian by up to 20km
• release of pressure along 1200km of fault line/plate boundary
• sea retreated in thailand
• 24km high + 13.5m/s speed waves
• LIDC/ EDC not prepared and struggle to alert and evacuate so more died
59
hazard/impacts of the boxing day tsunami?
• 290,000 killed
• 1.7 bil homeless
• 2.9 mil economic loss
• oil spill
• effected 12 countries
• infrastructure destroyed
60
identify the four tectonic plates and the fault closest to there the turkey syria earthquake occured?
anatolian plate, eurasian, african and arabian
• east anatolian fault
61
explain the factors which made the earthquake so deadly? (turkey syria)
- magnitude of 7.8
- broke along a 100km fault line
- shallow focus
- unsturdy buildings
- occured early in the morn
62
differences between syria and turkey with the earthquake?
syria at war for many years, less of prep- already trying to recover
both EDCs - bad infrastructure
63
explain how the strike slip earthquake occured in turkey/syria?
rocks beneath surface contain points of weakness, movement cause the rocks to deform, when stress exceeds the strength of the rock, it fractures along a fault
64
dif between earthquake magnitude and intensity?
mag- energy released at the epicentre (richter then MMS)
intensity- (MMIS) impact of the earthquake on people
65
what are the three types of volcano?
shield, composite, hotspot
66
explain the shield volcano feautures
runny less viscous lavq
sloped sides
constructive plate
less explosive/ destructive
balsatic lava
no layers
67
explain the features of a composite volcano
more vicious lava
steep sides
more destructive
alternate layers of ash and lava
68
features of a hotspot volcano?
magma rises through crust away from plate boundaries
new volcanic island forms
cindercone- most common- smaller
69
what are the three magma types?
basalt, andesite,
rhyolite
70
what is the silica content of each magma type
basalt: 45%-51%
andesite: 52%-65%
rhyolite: 68%-77%
71
whats the temperature of the three magma types?
basalt- high
andesite- medium
rhyolite- lowest
72
whats the viscocity of each magma type
basalt- low
andesite- medium
rhyolite- high
73
how easy is the gas escape from each magma type
basalt- easy
andesite- medium
rhyolite- hard
74
whats the eruptive style of each three magma type
basalt-
continual
andesite- mixed
rhyolite- explosive
75
describe what the mount ontake eruption looks like
large spew of ash, cloud, tiny rocks
falling like hailstones so they couldnt breath
30 dead
many injured
composite
76
describe what the mount kilauea looks like
hotspot volcano
homes damaged
slow moving lava
steam
erupting continuously
77
define a hazard
percieved natural event that had the potential to threaten both life and property
78
define a disaster?
reality of a hazard happening when it causes a significant impact on a vunerable population
79
what does the UN define a distaster as?
a serious disaster of the functioning of a community or society involving widespread human material economic or environemntal loss or impcr
80
what makes a place vunerable to a tectonic hazard?
war and conflict
level of infrastructure
economic capacity to recover
less awareness
population
location to coast
81
what are the 5 factors to understanding risk?
• unpredictablilty
• lack of alternatives - people stay in hazardous areas for multiple reasons
• dynamic hazards - the threat from hazards fluctuates and human influence can play a role
• cost benefit- the benefit from staying in a hazardous location may outweigh the risk
• russian roulette reaction- the acceptance of the risk as something that will
happen whatever you do
82
what is the hazard risk equation?
risk= hazard x exposure x vunerablility/manageability
83
what is the pressure and release PAR model?
progression of vunerability -> hazard = disaster
84
lava flows:
• what?
• p or s
• case study example
• streams of lava erupted from a volcano onto earths surface
• p
• kilauea hawaii 2018
- may to august lava flowed, 17mph, destroyed 700 homes
85
pyroclastic flow:
• what?
• p or s
• case study example
mixture of hot rock, lava, ash and gas ejected from a volcano during an eruption
• P
• fuego guatemala
- speeds of 450mph for miles
- temp ranged between 200c to 700c
- 69 deaths
86
tephra:
• what?
• p or s
• case study example
• pieces of volcanic rock and ash released into the air during eruptions
• P
• iceland 2010, reached altitudes of 30,000 ft covering large areas of NW europe
- disrupts flight paths for a week, evacuation to prevent inhilation
87
gas eruptions:
• what?
• p or s
• case study example
• magma contains gases which are releases during an eruption
• p
• mt pinatubo philipinnes 1991
- produced 20 mil ton of sulphur dioxide
- cooled earth for 3 years by 0.6c
- rose to a height of 32km
88
lahars:
• what?
• p or s
• case study example
• masses of rock, mud, water that move very quickly down the sides of a volcano
• S
• nevado del ruiz columbia
- pyroclstic flow melted 10% of snow and ice on volcano
- travel up to 60kmh
- water reached depths of 50m
- killed 23,000
89
jokulhaup:
• what?
• p or s
• case study example
• heat of volcano melts snow and ice in a glacier
• S
• iceland 2010- melted through 200km of thick ice
- widespread evacuation + ring road
- flood reached peak discharge
90
in recent years the number of recorded hazards has?
increased
91
the number of disasters has?
decreased
92
reasons for n of disasters decreasing?
more prep - decrease the impacts of events
more/ better equipment to detect
93
the type of disaster that is
most common is ?
hydrological
94
the least common type of disaster is?
climatological
95
what is EM-DAT?
world wide data base on disaster statistics
96
what affects the reliability of data?
• primary or secondary hazards/impacts - data could be immediate - not including secondary info
• location of disaster - less data in LIDCs
• priorities of the government - could cover something up for deception or more money if it looks worse
• timescale of disaster - not immediate - wait for secondary hazards - data not accurate
97
what is a mega disaster?
large scalee, pose problems for effective management and require co ordinated usually international responses
2000+ deaths, 200000 homeless
98
features of iceland 2010?
• european airspace shut down
• tourism and airline industries
lost significant income due ti the fact people could not move
• nissan plant in japan had to halt as they couldnt send parts to ireland
99
whats features of japan
2011 disaster?
• 5% loss in overall GDP
• damage to nucleur plant
• tokyo and sony halted production
• germany and italy shut down their nuclear reactors for new ones
100
what are the four stages of the hazard management cycle?
mitigation
prep
response
recovery
101
what does each stage of the hazard management cycle do?
mitigation - preventing hazard and minimise effects - land use zoning
preparation - prep to deal before
response - coping with disaster
recovery - after hazard, long term build homes, short term immediate needs
102
what are the key players?
emergency responders
businesses
community groups
international organisations
charities
103
what are the most effective key players and why?
aid doners - give stuff to help initially and LT
communities - limited resources but straight away
insurers - economical help buildings and businesses etc
NGOs - provide funding and shelter etc in all stages of the cycle
104
what is an example of a multi hazard zone?
japan, port au prince
105
benefits of tectonic
hazard profiles and negatives?
good to compare same hazard
• dif to compare dif hazards wto degree of inaccuracy
106
once hazard profiles are made govs can….
• invest in evac in high risk areas
• land use zoning
• awareness espec in high risk areas
107
why is hazard profiling bad?
wto economic funding nothing can be done
108
higher HD means?
more science available - more accurate stats
109
how to predict volcanoes?
gas release - levels of sulphur
•. thermal imaging
• seismometer
• boreholes
110
what is hazard
managment and eg
govs and
organisations work together to protect people from natural hazards
• aims to aboid or reduce loss of life
- provide help to those affected
- ensure a rapid and effective recovery
111
how have NGOs helped?
• 500,000 tents, 6 mil blankets, safe water food + clothing
• ST - roads rebuilt, water supplies, reestablished
• LT - 60,000 rebuild livelihoods, tools to grow crop
112
what are the key players (5)
- emergency responders
- businesses
- community group
- international organisations
- charities
113
what are the four stages of the hazard management cycle?
mitigation, preparation, response, recovery
114
explain the mitigation stage of the hazard management cycle?
- preventing hazard events or minimising their effects
• land use zoning
• building protective structures eg sea defences for tsunamis
before n after hazard
115
explain the preparation stage of the hazard management cycle?
preparing to deal with a hazard
- before hazard
- develop plans etc
116
explain the response stage of the hazard management cycle?
(occurs after hazards)
- response
- coping with disaster
eg search and rescue
117
explain the recovery stave of the hazard management cycle ?
get back to normal
(after hazard)
short term : provide essential health and safety
long term : rebuilt home etc
118
what stage of the hazard management model is most important in haiti?
response and recovery sunce its an LIDC, because they cant afford ti have good infrastructure for mitigation
119
ACs such as Japan, whats the most important stage of the hazard managenent cycle,
mitigation as they can afford it
120
is crisis mapping a mitigation or adaptation?
- adaptation
121
is land use mapping a mitigation or adaptation strategy?
mitigation
122
is high tech monitoring a mitigation or adaptation teq?
adaptation
123
is diverting lava flows a mitigation or adaptation strategy?
mitigation
124
is hazard resistant buidlings mitigation or adaptation?
mitigation
125
is modelling hazard impact a adaptation or mitigation teq?
adaptation
126
is GIS mapping a mitigation or adaptation tech?
mitigation
127
is public education a mitigation or adaptation tech?
adaptation
128
is community preparedness and adaptation tech?
adaptation
129
describe crisis mapping?
crowd source info to accurately map areas struck by disaster and send aid/help
130
describe land use mapping?
local gov planners regulate how land in a community may be used
131
describe high tech monitoring?
GIS: helps create hazard maps and manage hazards effectively
Early warning systems: scientific instruments detect a sign -> alert
Mobile phones:
rapid warnings + communications
132
where is crisis mapping been used before?
• 2010 Haiti earthquake
133
where is land use mapping used?
common in ACs less so in EDC/LIDC
134
where has high tech monitoring been used before?
2011 japan
135
diverting lava flows - mitigation or adaptation strategy?
mitigation
136
hazard resistant buildings - adaptation strategy?
mitigation
137
modelling hazard impact - mitigation or adaptation strategy?
adaptation
138
GIS mapping - mitigation or adaptation strategy?
mitigation
139
public education - mitigation or adaptation strategy?
adaptation
140
community preparedness - mitigation or adaptation strategy?
adaptation
141
explain diverting lava flows
using barriers or digging channels
- however, sometimes ineffective is path is hard to predict, terrain not suitable, directs lava to another place
142
when was diverting lava flows used??
Iceland in 1973
143
explain hazard resistant buildings?
protecting life and property by avoiding fallen debris and collapsing buildings
144
when was hazard resistant buildings used?
effective in developing countries
145
explain modelling hazard impact?
computer models allow scientists to predict impacts of hazard events - info fed to computers - model the impacts
146
where would modelling hazard impact be used?
ACs
147
explain GIS mapping?
identify where evacuation routes should be placed or to help with rescue and recovery options
148
explain public education?
good education and public awareness to reduce vunerablility
149
explain community preparedness?
develop suitable plans for at risk areas best for low income areas
150
when was/would GIS mapping be used?
nepal 2015 earthquake
151
when was/would public education be used?
Japan children do drills 4x a year
152
when was/would community preparedness be used?
2004 indian ocean tsunami - Thailand tribe advised movement to hilltop - 200 saved
153
what is the park model also known as??
the disaster response curve
154
what's the aim of the park model?
show the effects of a hazard on quality of life over a sequence of time
155
what are factors the park model take into account?
hazards are inconsistent
all hazards have dif impacts + response
ACs recover faster
156
who discovered the theory of continental drift?
alfred wegener
157
what is the jigsaw fit theory?
continents can be fitted together like a jigsaw - shows they were all together (Pangea)
