Exam 2 - Earthquakes Flashcards
1
Q
Every earthquake releases these
A
aftershocks
2
Q
Each individual earthquake releasing its own seismic waves
A
Aftershocks
3
Q
What is an earthquake?
A
vibration of the Earth produced by rapid release of energy
4
Q
Fault line
A
smaller than a plate
5
Q
What is found anywhere along any plate?
A
fault line
6
Q
What is a gigantic fault
A
Boundary
7
Q
The hypocenter is what
A
the focus of an earthquake
8
Q
Location inside the crust where earthquakes are intiated
A
Hypocenter
9
Q
Epicenter
A
location on surface directly above the focus
10
Q
Largest quake in the world
A
Chile, 1960 M=9.5
11
Q
What do all of the largest quakes in the world have in common?
A
they are all at subduction zones
12
Q
What produces the largest magnitude earthquakes?
A
subduction zones
13
Q
Where are the most earthquakes?
A
Around the rim of fire
-West pacific, subduction zone
14
Q
What are the 3 major stresses applied to rocks?
A
- Compression
- Tension
- Shear
15
Q
Stress:
Rocks that are squeezed together
A
Compression
16
Q
Stress:
Rocks shorten horizontally and thicken vertically
A
Compression
17
Q
Stress:
Convergent boundaries; where faults are formed
A
Compression
18
Q
Stress:
Rocks thinned out and pulled apart
A
Tension
19
Q
Stress:
Rocks lengthen horizontally and thin vertically
A
Tension
20
Q
Stress: Divergent Boundaries (mid-ocean ridges)
A
Tension
21
Q
Stress:
Rocks slide past one another
A
Shear
22
Q
Stress:
Causes displacements along fault zones or by ductile flow
A
Shear
23
Q
Stress:
Transform boundary
A
Shear
24
Q
In faults, rocks will move in ______ directions always
A
opposite
25
Faults are
fractures in the crust where rocks move in opposite directions
26
Something that is "thin as a sheet of paper"
Fault plane
27
Between 2 blocks of the crust
fault plane
28
Two types of walls in faults
1. Hanging Wall
| 2. Footwall
29
Block of rock below the fault plane
Hanging wall
30
Faults that move vertically
hanging wall
31
Block of rock above the fault plane
Footwall
32
2 vertical movements of faults
1. Normal
| 2. Reverse
33
Footwall that moves up relative to hanging wall
Normal vertical movement
34
Normal vertical movement stress =
Tension
35
Footwall moves down relative to hanging wall
Reverse vertical movement
36
Reverse vertical movement stress =
Compression
37
Normal vertical movement tectonic regime
Divergent boundaries
38
Reverse vertical movement tectonic regime
Convergent boundaries
39
Thrust fault
reverse fault that is at a 45 degree or less from the surface of the Earth
40
Fault that is shallow
Thrust fault
41
Tectonic regime of thrust faults
convergent boundaries
42
Horizontal movement of faults
strike slip fault
43
Stress of strike slip fault
Shear
44
Two types of strike slip faults
Right lateral and left lateral
45
How do you identify the type of strike slip fault
you must be looking across the fault to identify it
46
Tectonic regime of strike slip faults
Transform boundary
47
Fault scarp
nothing but exposed fault plane
48
Baja Earthquake of 2010 was a
fault scarp
49
What type of fault is the San Andreas Fault?
right lateral strike slip fault
50
What kind of boundary is the san Andreas fault?
transform boundary
51
Energy released at the focus by an earthquake
Seismic waves
52
2 types of waves
Body waves and Surface waves
53
2 types of Body waves
P-waves and S-waves
54
Which body wave reaches seismograph first and the fastest?
P-wave
55
What kind of waves are P-waves?
Compressional
56
What does it meant that p-waves are compressional
they push and pull through the rocks n in the same direction of the waves
57
P-waves go through
solids, liquids, gases
58
P-waves can travel through what parts of the earth
- Atmosphere
- Inner core
- mantle
- outer core
- Water
59
Type of body waves second to arrive to seismograph station
S-Waves
60
S-waves are
Shear wave
61
Body waves that move in an up and down motion
S-waves
62
Which waves only travel through solids?
S-Wave
63
The fact that s-waves only travel through solids prove what
that the outer core is molten
64
The _______ away from the epicenter, the ______ the interval between pwave and swave
Farther; bigger
65
More destructive than body waves
Surface waves
66
2 types of surface waves?
1. Love wave
| 2. Rayleigh wave
67
Surface wave with a side to side motion
love wave
68
The love wave only moves through
solids
69
Type of wave that is deadly to buildings because of its side to side motion
Love waves
70
Which wave is last to arrive
Rayleigh
71
Rayleigh has a _____ motion
rolling
72
Why is the rayleigh wave more destructive
because it is free to move
73
The rayleigh wave can travel through
anything
74
Do earthquakes kill people?
no buildings do
75
3 type of scales to measure earthquakes
- Mercali Intensity Scale
- Richter magnitude scale
- Seismic moment scale
76
Qualitative assessment of the damage and the shaking of the earthquak
Mercali intensity scale
77
Scale for mercali intensity scale
1 to 12
78
What was the first attempt at measuring the power of an earthquake
Mercali Intensity scale
79
What earthquake scale is the most widely used
Richter Magnitude scale
80
Earthquake scale that is the measure of energy released at the focus
Magnitude Richter Scale
81
Each richter increment releases __ times more energy
32
82
_____ does not correlate with _____ _____
magnitude; death toll
83
In the richter scale, the amplitude is measured as
the height between the top of the seismograph and the middle line
84
Which earthquake scale can measure any earthquake
Seismic Moment scale
85
Seismic moment scale is the function
of the rupture area, average slip of fault and the rock strength
86
Which earthquake scale is most accurate of them all
Seismic moment scale
87
Which earthquake scale is he only one that works for very large earthquakes
Seismic moment scales
88
What are the 3 largest Magnitude Earthquakes
- Chile, 1960
- Sumatra 2004
- Alaska 1964
89
In the Chile earthquake, the seafloor was disrupted causing a
tsunami
90
What killed most of the people in the Chile megathrust earthquake?
The tsunami
91
What was the largest earthquake in the U.S.?
Alaska 1964
92
What 2 things do all of the largest earthquakes have in common?
They are all at subduction zones and they are values taken from moment scale
93
The Turkey 1999 earthquake was an example of
pancake collapse of buildings
94
Why do pancake collapses happen?
when structures are made with unreinforced cement/ concrete
95
The 5 causes of destruction from earthquakes
1. Ground shaking and acceleration
2. landslides
3. tsunami
4. liquefaction
5. Fire
96
Why do valleys shake more than mountains?
Because sediments accelerate more and more intensely because they lack density
97
How do landslides occur?
ground gives way during earthquakes
98
Which cause of destruction from earthquakes kill more people than the others?
tsunamis
99
What happens in liquefaction?
loose, weak soils start moving, the ground starts flowing
100
What happens to buildings above liquefaction?
The foundation is sheared off and completely falls
101
What happens in a fire caused by an earthquake?
there is a rupture of gas and water mains
102
What are the safest buildings?
Wooden houses, and steel-framed buildings
103
What would happen to the CA aqueducts if the San Andreas Fault is activated
no power and no water if these are affected
104
Will California eventually fall into the earth?
No; it's a plate moving northwest
| - It's fate is to subduct
