Physical Geography Hazardous Earth Flashcards
(118 cards)
1
Q
Average depth of continentalcrust
A
35km
2
Q
Density of continental crust
A
2.6 kg/m^3
3
Q
Depth of oceanic crust
A
10km
4
Q
Density of oceanic crust
A
3kg/m^3
5
Q
Depth of lithosphere
A
crust-100km
6
Q
Characteristics of the lithosphere
A
Rigid
7
Q
Depth of Asthenosphere
A
100-300km
8
Q
Characteristics of asthenosphere
A
Plastic
9
Q
Depth of mesosphere
A
300-2900km
10
Q
Characteristics of mesosphere
A
Solid
11
Q
Depth of core
A
2900-6400km
12
Q
Inner core characteristics
A
Solid iron and nickel
13
Q
Outer core characteristics
A
liquid
14
Q
When did maps of seismic activity emerge
A
1960s
15
Q
Evidence for continental drift and plate techtonics
A
Plate movement
geological evidence
biological evidence
paleomagnetism
the age of sea-floor rocks
16
Q
Define plate movement
A
convection currents due to rising parts of the asthenosphere that reach lithosphere, dragging the techtonic plates.
17
Q
Who originally proposed continental drift
A
Alfred Wegener 1912
18
Q
Examples of geological evidence for plate techtonics
A
Fit of SA and africa
Glaciacion of India, Australia
19
Q
Biological evidence for plate techtonics
A
Glossopteris fossil found in Antarctica, Australia, India
Mesosaurus in SA and Africa
20
Q
Define paleomagnetism
A
Changes in earths polarity is recorded in minerals on the sea floor.
21
Q
How does the age of the sea floor rocks present evidence for plate techtonics
A
oldest sediments found near continents, younger deposits found out in oceans.
Large scale trenches suggest that crust subduction into the asthenosphere
22
Q
Define ridge push
A
Plate pushed by the weight of a mid-ocean ridge
23
Q
Define slab pull
A
Plate pulled by the weight of its cold, dense subducting region.
24
Q
Define convection currents
A
Plate dragged by a convection current in the mantle
25
What boundry occurs during divergent plate movement
Constructive boundry
26
What boundry occurs during convergent plate movement
destructive (oceanic to continental)
27
What boundry occurs during transform plate movement
conservative
28
What boundry occurs during convergent plate movement (continental - continental)
collision
29
What boundry occurs during convergent plate movement (oceanic - oceanic)
destructive (oceanic to oceanic)
30
What type of lava is in an explosive eruption
Acidic
31
What type of lava is in an effusive eruption
Basic
32
Properties of pyroclastic flow
Explosive eruption
Up to 500 degrees
Poisonous
Faster than 100mph
33
Properties of tephra
Explosive eruption
Tiny fragments of rock thrown by an eruption (often creates volcanic ash)
34
Properties of Poisonous gas
Explosive and effusive
Carbon monoxide, Carbon dioxide, sulfur dioxide
produces acid rain
35
Properties of a lahar
Explosive eruption (must have tephra)
Fast flow of mud and tephra produced by heavy rains after an eruption
local, up to 50kmph
36
Properties of a tsunami in an eruption (+speed)
Explosive eruption
wave speed up to 600kmph
37
Define Jokulhlaup
Explosive and effusive eruptions
sudden release of glacial melt water
38
Define volcanic winter
Effusive and explosive
Global scale, can cause food shortages.
Sulphur dioxide
39
What are techtonic plates made of
Crust and lithosphere
40
What is a volcano
A landform created by eruption of molten rock
41
Define volatile
Evapourates without energy (water)
Rock can now melt as volatiles have been added (destructive boundry)
42
Define decompression
No longer being pushed down by crust
Allows rock to melt and erupt (shield)
43
Plate boundry of basic lava
Constructive/ divergent
44
Type of melting/eruption for basic lava
decompression
45
Which layers melt to form basic lava
Mantle
46
Viscocity and silica content of basic lava
Not viscous, less silica
47
How are gasses vented in basic lava
Vented steadily
48
What types of rocks are produced by basic lava
Basalt
49
Temp of basic lava
Up to 1200
50
eruption type of basic lava
effusive
51
Volcano shape of basic lava
sheild, fissure
52
Plate boundry of acidic lava
destructive
53
Type of melting for acidic lava
Addition of volatiles during subduction
54
Which layers melt to form acidic lava
oceanic crust
55
Viscosity and silica content of acidic lava
Viscous, high silica
56
How are gasses vented in acidic lava
trapped until violent eruption
57
Type of rock produced by acidic lava
Andesitic
58
Temp of acidic lava
650 - 1000
59
eruption type of acidic lava
explosive
60
Volcano produced by acidic lava
composite / strato
61
What is VEI and what does it measure
Volcanic explosivity index
Magniude (how much material)
Intensity (how fast)
62
What is VEI and what does it measure
Volcanic explosivity index
Magniude (how much material)
Intensity (how fast)
63
What is the term for the limit where rock cracks
threshold
64
What happens when stress reaches threshold
plates jolt
65
Define focus
where the rock cracks underground
66
Define seismic waves
stress release causing jolts, vibrate through rocks on the surface
67
epicentre
point on surface above focus
68
What is the wadati-benioff zone
Zone of EQs next to destructive plate boundry
70 - 700km deep
69
What does the richter scale measure
magnitude (amount of energy released on a logarithmic scale)
70
What does the modified mercalli scale measure
Damage / intensity (qualitative descriptions of damage in 12 catagories)
71
What does the moment magnitude scale measure
Magnitude (how much ground shaking occurs)
72
Define P waves
Primary
Ground shakes laterally
moderate damage
fast
73
Define S waves
Secondary
Ground shakes vertically
slight damage
average speed
74
Define L waves
Surface
Ground shakes rolling
Severe damage
slow
75
Effects of liquefaction
Structures tilt and sink
Fine grain sands behave like water
76
Define pillow lava
Underwater divergent boundry
basaltic lava
77
Landforms created by divergent boundrys
In water - mid ocean ridge
On land - rift valley
78
Describe formation of rift valley
Rising mantle rock
Pushes crust into dome
Divergence (uplift) causes crust to fault and crack
Rock is weakened - dome subsides
Creates steep valley sides + flat floor
79
How do some volcanoes become calderas
Magma chamber empties and unsupported rock above collapses
crater and collapsed roof remain
80
Moment magnitude of Japan earthquake
9.0
81
Date of japan earthquake
2011
82
Height of tsunami japan 2011
40
83
How many people died japan 2011
16,000
84
GDP of Japan
39,000
85
Mitigation against the event japan 2011
sea wall
86
Mitigation against vunerability japan 2011
research + monitoring
building design
education
87
Mitigation against losses japan 2011
rescue workers (100,000 from armed forces)
slow recovery from fukushima
rehearsed plans
88
Moment magnitude of Haiti eq
7.0
89
date of haiti eq
2010
90
how far was epicentre from port au prince
25km
91
building faliures? haiti 2010
pancake collapse
92
how many people died haiti 2010
230,000
93
how many ppl made homeless haiti 2010
2.3 million
94
Mitigation against the even haiti 2010
none
95
Mitigation against vunerability haiti
new eq proof buildings
world bank waived dept for 5 years
96
Mitigation against losses haiti
3500 US troops
NGO for emergancy shelters, food + water
97
GDP per capita of Haiti
1,800
98
GDP of italy
36,000
99
economic impacts of mt etna eruption
tourism decrease
orange + vineyards destroyed
100
mitigation against the event etna
earth barriers
concrete blocks
101
mitigation against vunerability etna
volcano monitoring
promt evacuations
102
mitigation against losses etna
families can afford insurance
government compensation
well resourced public services
103
GDP of indonesia
4,000
104
how far did the pyroclastic flows reach marapi
15km
105
economic impacts of marapi
livestock killed
farms + crops destroyed
106
How many poeple died merapi
367
107
Mitigation against the event merapi
river channels cleared to contained lahars
108
mitigation against vunerability merapi
evacuation
gradual improvements to monitoring
BNBP est 2008 to monnitor voclanoes
109
mitigation against losses merapi
limited resourced from gov
temporary shelters in safe zones
subsistance farmes (no food)
110
How is a mid ocean ridge formed
Plates seperated by slab pull and ridge push
Magma rises from decompression
Magma solidifies into pillow lava
Causes creation of mid ocean ridge
111
Why do people not move from techtonically active regions
stasis
112
What can the Hawaiian islands and indonesian islands be called
Archipelago
113
When was the merapi eruption
2010
114
When was the etna eruption
2016
115
Buildings in haiti
Built out of breezeblocks to protect agianst hurricaines
116
What is the risk equation
risk= vulnerability/capicity to cope
117
How often does the earth polarity change
every 500,000 years
118
Extra paleomagnetism facts / sea floor spread
new rocks either side of mid ocean ridge
creates ridge push
alignment of iron particles in rocks settle as rock solidifies
