FINAL Flashcards
1
Q
Earthquakes
A
ground shaking caused when the pressure in the earth is stronger than the rock, which breaks it at a fault
2
Q
Fault
A
fracture in earth’s surface on which sliding occurs, most are at an angle
3
Q
“stick-slip”
A
when a fault overcomes the friction between them
4
Q
focus/hypocenter
A
pointy at which original rupture occurs and energy is released during an earthquake
5
Q
epicenter
A
point on earth’s surface directly above focus
6
Q
3 types of waves
A
come in this order: P, S, surface
P- Primary, fastest, can move through any medium
S- Secondary, can only move through solid
7
Q
seismograph
A
measures ground motion from an earth quake, uses 3, 1 vertical and 2 horizontal
8
Q
how to find epicenter
A
time lag between types of waves increases the farther away you are
9
Q
Mercalli intensity scale
A
defines intensity by AMOUNT OF DAMAGE, on a scale from I to XII
10
Q
Richter magnitude scale
A
based on amount of GROUND MOTION, on a scale from 1-9 ish, logarithmic so every value is 10x more powerful
11
Q
Raleigh waves
A
pass like waves, (arrows pointing in 2 directions)
12
Q
Love waves
A
waves move laterally, (towards each other)
13
Q
Damage due to ground motion depends on…
A
- closeness to epicenter
- underlying ground being solid or soft
- building construction
14
Q
Landslides / Avalanches
A
ground on steep slope gives way and tumbles downhill
15
Q
Sediment liquefaction
A
sediment containing poe water becomes a slurry, can create sand volcanoes
16
Q
Fires (damage due to earthquakes)
A
spread from lamps and broken gas lines
17
Q
What can cause a tsunami?
A
submarine fault, landslide, volcano
18
Q
Deep water tsunami
A
height is 1/2 a meter, but WHOLE BODY of ocean is moving, lots of energy, very fast
19
Q
Shallow water tsunami
A
piles up due to friction, gets up to 10 meters high (30 feet)
20
Q
megatsunami
A
10 to 20 times bigger
21
Q
tsunami prediction
A
seismograph records earthquake, sensors pick up speed of water, warning issued.
22
Q
tsunami runup
A
size of tsunami wave when it gets to shore, unpredictable by tsunami warning system
23
Q
steps to minimize damage
A
- avoid runup areas
- evacuation plan
- avoid new development in high risk areas
- design construction to minimize damage
24
Q
Earthquakes at divergent boundaries
A
not very dangerous, shallow focus
25
earthquakes at Transform boundaries
between shallow and deep, could be minor or major
26
locked fault
section of fault where its stuck, so stress is spread out over more fault
27
earthquakes at convergent boundaries
subduction zones, deep - shallow focus, could be minor or major
28
Benioff-Wadati zone
subduction zone where plate is forced under
29
intraplate earthquakes
1. Collision zone
2. ancient weak fracture zones
3. extensions of mid ocean fracture zones
30
Collision zones
convergent zone where neither plate goes down
31
Ancient weak fracture zones
many are failed rift valleys,
32
fracture zones
created as transform faults between segments of spreading ridges
33
induced earthquakes are due to
1. changing stress field
| 2. increasing pore pressure underwater
34
examples of induced earthquakes
1. reservoirs
2. withdrawal of oil or water
3. rockbursts
4. underground nuclear testing
5. deep well injection
35
predicting an earthquake
1. identify seismic zones, or clusters of epicenters
| 2. identify seismic gaps, a gap of years where an active fault has not shaken
36
foreshocks
lil earthquakes before a big one
37
Earthquake warning system
Japan uses it, measures P waves and sends out an alert, slows bullet train and turns off gas lines.
38
Differential stresses
1. compression (squeezing)
2. tension (stretching)
3. shear (twisting)
39
Deformation
small scale, foliation and joints
| large scale, folds and faults
40
Kinds of deformation
1. brittle - material breaks
| 2. ductile - material changes shape
41
Behavior of crust depends on.....
1. composition
2. rate - fast=brittle
3. temp - higher temp=more ductile
4. pressure - higher pressure=more ductile
42
hanging wall v. foot wall
hanging wall hangs over and foot wall is under
43
strike
angle bw horizontal line and true north measuring a fault
44
dip
angle b/w horizontal and steepest slope (gives slope)
45
dip slip
sliding up or down in dip direction
46
strike slip
sliding horizontally
47
oblique slip
has components of both strike slip and dip slip
48
normal faults
hanging wall moves DOWN, due to extensional forces, CRUST LENGTHENS, Basin range in US (dip slip)
49
reverse and thrust faults
hanging wall moves UP, due to compressional forces, CRUST SHORTENS, reverse is greater than 35 degrees and thrust is less - Himalayas (dip slip)
50
strike slip faults
due to shear force, transform plates
51
slicken slides
rocks along a fault rub against each other and make each other smooth and groovy
52
Folds
caused by compressional forces
53
Anticline
fold where center bows up
54
syncline
fold where center bows down
55
Hinge
largest curvature in a series of folds
56
plunging anticline or syncline
happens when hinge is not horizontal
57
Istostacy
describes buoyancy of lithospheric plates
58
Archimedes principle
floating thing in water - mass of water displaced is mass of object
59
Rules of istostacy
1. thicker lithosphere rises higher
2. less dense lithosphere rises higher
3. loading it causes it to sink and vice versa
60
isostatic compensation
places that are still moving up or down
61
fossil fuels
altered remains of previously existing plants and animals, stored solar energy
62
3 steps of making coal
1. organic matter is buried in oxygen-poor environment
2. compaction and partial decay
3. deep burial drives off everything but carbon
63
grades of coal
lowest: lignite (70%)
bituminous (85%)
highest: anthracite (95%)
64
Strip mining
shallow seams, overburden removed and coal is taken out, ruins top soil
65
underground mining
tunnels dug, dangerous bc of collapse, explosions, or black lung disease
66
oil and natural gas
hydrocarbons, the longer the hydrocarbon the more viscous
67
4 steps of making oil or gas
1. plankton and algae die and end up in oxygen poor environment
2. lithtification to black organic shale
3. burial
4. increase of Temp and pressure
68
Requirements for a rock to become oil
1. high porosity
2. high permeability
3. trapping mechanism
69
Oil traps need
1. Seal Rock
| 2. Oil trap geometry
70
Peak Oil
the rate of petroleum production over time follows a bell curve, depends on discovery rate, production rate, and total production.
71
M. King Hubbert
Predicted US oil production would peak in 1970
72
Consequences of peak oil
Second half of oil is difficult to get to, more accidents, might take more energy to get to than it's worth
73
Methane hydrate
Frozen methane and water which becomes natural gas
74
Hydraulic fracturing
injection of high pressure solutions into permeable rocks to extract natural gas
75
Consequences of fracking
1. Construction of drill
2. Water consumption
3. Groundwater contamination
4. Flowback, or chemicals coming back up w natural gas
76
Mass movement
gravity-caused transport of material
77
Angle of repose
steepest slope a pile of sediment can have and remain stable, increases with grain SIZE and grain ANGULARITY
78
factors affecting likelihood of mass movement
1. vibration
2. presence of water
3. vegetation
79
Creep
gradual movement, normally due to freeze and thaw cycles
80
Slump
block of material comes off in spoon-shaped glide horizon
81
mud flow
water mixed with sediment, can move up to 100 miles an how. If sediment pieces are large enough its called debris flow
82
avalanche
air and debris traveling up to 250 mph
83
landslide
bedrock detaches from slope and SPEEDS downhill, if it falls in a body of water it can create a megatsunami.
84
Rockfall
rocks falling from a cliff
85
Ways to combat mass movement
1. retaining wall
2. avalanche shed
3. rock bolts
4. terracing
5. revegetation
6. relocate water flow
7. lower water table
8. rip raps absorb energy along coasts
86
submarine slump
blocks that fall off underwater
87
submarine debris flow
larger clasts and mud matrix
88
turbidity current
sediment in water that moves really fast and is caused by earthquakes sometimes
89
wave refraction
part of wave is closer to shore, energy is focused on headlands, and it straightens out the coastline. ALSO, means it transports sand in the direction of the refraction.
90
longshore drift
Movement of sand by wave refraction, methods put into place to keep it from affecting the shape and position of shore
91
groins and jetties
methods put in place to stop longshore drift, sand piles up on one side and erodes on other side
92
undertow
wind pushes water to shore, water flows out underneath
93
rip current
when undertow is focused to a certain spot bc of reefs or sand bars, creates STRONG undertow
94
fringing reef
forms around volcanic island
95
barrier reef
reef circling lagoon, w small island
96
atoll
remnant of volcano left above sea level
97
emergent coasts
sea level drop, caused by glacial period normally, can happen in interglacial periods when the ice takes pressure off of a space, and it retaliates upward (ISOSTATIC REBOUND)
98
submergent coasts
sea level rise caused by interglacial period, either drowned river valleys or drowned u-shaped valleys, AKA fjords
99
runoff
surface water moving downslope
100
Formation of drainage networks
SHEETWASH follows weaknesses in ground, erosion causes them to form streams and tributaries
101
dendritic drainage network
shaped like branches of a tree, forms where everything is pretty uniform
102
radial drainage network
radiate out from central point, often formed around volcanoes
103
annular drainage network
in concentric rings, typically over domes
104
rectangular drainage network
follows joints in bedrock
105
trellis
forms between drainage-resistant ridges
106
watershed
drainage network collects water from a region
107
drainage divide
separates watersheds
108
how does river change as you move downstream (longitudinal profile)
1. gradient decreases
| 2. carrying capacity decreases
109
floodplain
depositional part of river
110
types of floodplains:
1. braided river
| 2. meandering
111
oxbow lake
loop that's been cut off from a meander
112
flood frequency graph
define major interval flood limits, uses a year scale to define how often a type of flood will happen
113
channelization
water forced into a certain spot, increases chance of flood, higher speed of water
114
whitewater
fast water caused by steep gradient
115
hydraulics
turbulent flow caused by interaction w sides and rocks
116
hole
place under waterfall where water circulates
117
keeper
a hole with no surface escape direction
