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Flashcards in Unit 3 / Final Deck (237):
1

Which main layer of Earth is solid, can conduct P-waves and S-waves, is rich in silicon and aluminum, and contains basalt and granite?

crust

2

Which main layer of Earth is solid, can conduct P-waves and S-waves, is rich in magnesium and iron, and contains periodite?

mantle

3

Which main layer of Earth is liquid, only conducts P-waves, and is made of iron?

outer core

4

Which main layer of Earth is solid, conducts faster P-waves, and is made of iron?

inner core

5

Which main layer of Earth has density of 4.5?

mantle

6

What density is the mantle?

4.5

7

Which main layer of Earth has a density of 10.7?

core

8

What is the density of the core?

10.7

9

What is the density of Earth?

5.5

10

Which specific layer of Earth has a density of 2.8?

continental crust

11

Which specific layer of Earth has a density of 2.9?

oceanic crust

12

What is the density of oceanic crust?

2.9

13

What is the density of continental crust?

2.8

14

What is the meaning of "lithos"

stone

15

What is the meaning of "asthenos"

weak

16

lithosphere

consisting of the crust and upper mantle, mechanically rigid, strong

17

asthenosphere

the upper layer of the earth's mantle, below the lithosphere, mechanically plastic, part the tectonic plates slide around on, weak

18

Which is older, oceanic crust or continental crust?

continental crust

19

What is oceanic crust mostly made of?

basalt

20

How old is the oldest oceanic crust?

270 million years

21

Which is more dense, oceanic crust or continental crust?

oceanic crust

22

Why is oceanic crust denser than continental crust?

lots of Mg (magnesium) and Fe (iron)

23

Why is continental crust less dense?

lots of aluminum and silicon

24

How old is the oldest continental crust?

3800 million years

25

Is oceanic crust homogenous or heterogenous?

relatively homogenous

26

Is continental crust homogenous or heterogenous?

very heterogenous

27

What rock does continental crust contain a lot of?

granite

28

What is the density of the upper mantle?

3.4

29

What volcanic rock is high in Mg and Fe and is typical of hot spots and the ocean crust?

basalt

30

What igneous rock is high in Al and Si and is typical of continent-continent collisions?

granite

31

What volcanic rock is found almost exclusively in volcanic arcs (subduction zones)?

andesite

32

Which rock is associated with subduction zones?

andesite

33

What are the 3 main types of plate boundaries?

divergent, convergent, transform

34

What are the 2 types of divergent boundaries?

1. continental rifts
2. mid-ocean ridge or rise

35

Which type of plate boundary involves plates moving apart?

divergent boundary

36

upwarping/doming

cracking (faulting) due to extension

37

Which type of plate boundary involves plates moving together?

convergent boundary

38

Which type of plate boundary involves plates sliding past one another?

transform boundary

39

What is an example of upwarping/doming?

Basin and Range

40

rift valley

thinning of crust, some volcanism

41

What is an example of a rift valley?

East African Rift Valley

42

Describe a linear sea.

shallow confined

43

What is an example of a linear sea?

Red Sea

44

seafloor spreading

the formation of new areas of oceanic crust, which occurs through the upwelling of magma at midocean ridges and its subsequent outward movement on either side

45

What is an example of seafloor spreading?

Mid-Atlantic Ridge
East Pacific Rise

46

Mid-Ocean Ridges and Rises

very thin crust, new basaltic crust created in axial valley

47

How is a mid-ocean ridge formed?

slow spreading forms a high narrow ridge

48

How is a mid-ocean rise formed?

fast spreading forms a low broad rise

49

What is an example of a mid-ocean ridge?

Mid-Atlantic Ridge

50

What is an example of a mid-ocean rise?

East Pacific Rise

51

What are the 3 types of convergent boundaries?

ocean-ocean, ocean-continent, continent-continent

52

Name the boundary: earthquakes are compressional, range from shallow to deep, Wadati-Benioff Zone

convergent

53

Name the boundary: shallow tensional earthquakes, 2 types

divergent

54

Name the boundary: shallow to intermediate earthquakes, intermediate strength compared to other 2 types of boundaries, generally no volcanoes, 2 types

transform

55

What is the process involved with an ocean-ocean boundary?

one oceanic plate subducts under another (subduction zone)

56

What boundary type and sub-type involve subduction zones?

Convergent, ocean-ocean

57

What are 4 examples of an ocean-ocean boundary?

Japan, Aleutians, Philippines, Marianas Trench

58

What two tectonic features are created by ocean-ocean boundaries?

deep sea trenches and island arcs with explosive volcanoes

59

What is the process involved with an ocean-continent boundary?

oceanic plate subducts under continent

60

What may happen or form at an ocean-continent boundary?

trench may fill with sediment, high mountain ranges, explosive volcanoes, granite (deep)

61

What are some examples of an ocean-continent boundary?

Andes, Cascades

62

What happens at a continent-continent boundary?

continental crust thrust over continental crust

63

What features are associated with a continent-continent boundary?

very high mountain ranges, very thick crust, deep crust can melt to form granite, usually no volcanoes

64

What are some examples of continent-continent boundaries?

Himalayas, Alps, Appalachians

65

How do subduction zones form volcanoes?

water from the subducting plate combines with melt below the upper plate to create steam which causes an 1800x expansion

66

deep sea trench

a long, narrow, deep depression in the ocean floor, typically one running parallel to a plate boundary and marking a subduction zone

67

Wadati-Benioff Zone

a deep active seismic area in a subduction zone. Differential motion along the zone produces deep-seated earthquakes

68

What are the two types of transform boundaries?

1. Oceanic Transform Faults & Fracture Zones
2. Continental Transform Faults

69

How are oceanic transform faults formed?

formed by opposing spreading directions between offset ridges

70

How are oceanic fracture zones formed?

scar left on plate beyond ridge offset

71

What's the difference between an oceanic fracture zone and an oceanic transform fault?

fracture zones are INACTIVE and transform faults are ACTIVE

72

What's an example of a continental transform fault?

San Andreas Fault

73

What is upwelling of hot material from deep in the mantle called?

mantle plumes

74

What is the origin of flood basalts and oceanic plateaus?

plume head

75

What do plume tails form?

hot spot tracks - linear island chains

76

How do plumes and tectonic plates relate?

plumes are in a "fixed" position in mantle, plates move over plume

77

linear island chain

string of seamounts/islands that become older away from active volcanism

78

What causes linear island chains?

plate movement over a hot spot (hot spot tracks)

79

What are 3 examples of a hot spot track?

Hawaii, Galapagos, Yellowstone

80

What does a continental hot spot track form?

string of inactive volcanoes caused by plate movement over hot spot, volcanic centers get older away from current hot spot location

81

continental flood basalts

continental equivalent of oceanic plateaus

82

How do continental flood basalts form?

huge eruptions of basalt that occur over very short periods (few million years)

83

What is an example of continental flood basalts?

Columbia River flood basalt

84

How do we know the internal structure of Earth?

tracking P-waves and S-waves, meteorites from space bodies with similar structures, iron meteorites, iron-nickel meteorites

85

What evidence is there for plate tectonics?

seafloor spreading, subduction, continental drift, scarring on Mid-Atlantic Ridge, coastline shape, fossil distribution

86

oceanic plateau

huge regions of the seafloor composed almost entirely of basalt (flood basalt)

87

What is an example of an oceanic plateau?

Ontong-Java Plateau

88

What's an example of a continental hot spot track?

Yellowstone

89

What are 2 examples of a linear island chain?

Hawaii and Emperor Seamounts, Galapagos Islands

90

What type and sub-type of boundary can form mountain belts?

convergent, continent-continent

91

What process forms mountain belts?

collision, a crumple zone is formed

92

What are 2 examples of a mountain belt?

Himalayas, Appalachians (as they formed 300 million years ago)

93

What type and sub-type of boundary forms a continental arc?

convergent, ocean-continent

94

What process forms a continental arc?

subduction

95

What are 2 examples of a continental arc?

Andes, Cascade Range (including Mt. St. Helens)

96

What process forms a continental rift?

rifting

97

What process forms a linear sea?

rifting

98

What process forms a mid-ocean ridge or rise?

seafloor spreading

99

What process forms an island arc and trench?

subduction

100

What process forms a transform fault or fracture zone?

faulting

101

What process forms a linear island chain?

mantle plume tail

102

What process forms a hot spot volcano or track?

mantle plume tail

103

What process forms an oceanic plateau?

mantle plume head

104

What process forms a flood basalt?

mantle plume head

105

Tectonically, where does a linear island chain occur?

intraplate (oceanic)

106

Tectonically, where does a hot spot volcano or track occur?

intraplate (continental)

107

Tectonically, where does an oceanic plateau occur?

intraplate (oceanic)

108

Tectonically, where does a flood basalt occur?

intraplate (continental)

109

At what type of boundary does a transform fault occur?

transform (continental)

110

At what type of boundary does a transform fault/fracture zone occur?

transform (oceanic)

111

At what type of boundary does a continental rift or linear sea occur?

divergent

112

At what type of boundary does a mid-ocean ridge or rise occur?

divergent

113

At what type of boundary does an island arc and trench occur?

convergent (ocean-ocean)

114

What is an example of a continental rift (upwarping and doming?

Basin and Range

115

What is an example of a continental rift (rift valley)?

East African Rift Valley

116

What is an example of a linear sea?

Red Sea

117

What are 2 examples of a mid-ocean ridge?

Mid-Atlantic Ridge, Mid-Indian Ridge

118

What is an example of a mid-ocean rise?

East Pacific Rise

119

What are 4 examples of an island arc and trench?

Mariana Islands and Trench, Japan and Japan Trench, Aleutian Islands and Trench, Sandwich Islands and Trench

120

What is an example of a transform fault (continental)?

San Andreas Fault

121

What are 2 examples of a transform fault/fracture zone (oceanic)?

Eltanin Transform Fault and Fracture Zone, Romanche Transform Fault and Fracture Zone

122

What is an example of a transform fracture zone?

Mendocino Fracture Zone

123

What is an example of an ocean island?

Iceland

124

At what type of boundary does an ocean island occur?

divergent

125

What two processes form an ocean island?

seafloor spreading, mantle plume tail

126

fault

surface that accommodates movement

127

The biggest faults are at ____ ____.

plate boundaries

128

Complete the sentence: Once a rock breaks, it tends...

to break again in the same place

129

What makes a fault active?

moved in last 10,000 years

130

How do earthquakes relate to faults?

earthquakes start when rocks stretch, then break along faults

131

Seismic/Earthquake waves propagate from the ____.

focus

132

epicenter

point on surface above focus

133

Complete the sentence: Earthquakes occur when the Earth...

moves along faults

134

Where do earthquakes occur?

mostly at plate boundaries

135

On the Richter Scale, each increment has __ times the motion and __ times the energy.

10; 32

136

What does the Richter Scale measure?

magnitude

137

What does the Mercalli Scale measure?

damage intensity

138

What are 2 US examples of an intraplate earthquake?

New Madrid (1811-1812, 3 at M8), Charleston (1886, M7.5)

139

intraplate earthquake

an earthquake that occurs in the interior of a tectonic plate

140

On the seismic hazard map of the US: Label number 1.

Cascadia Subduction

141

On the seismic hazard map of the US: Label number 2.

San Andreas Fault

142

On the seismic hazard map of the US: Label number 3.

Basin and Range

143

On the seismic hazard map of the US: Label number 4.

Rio Grande Rift

144

On the seismic hazard map of the US: Label number 5.

New Madrid
1811-1812
3 @ M8

145

On the seismic hazard map of the US: Label number 6.

Eastern Tennessee

146

On the seismic hazard map of the US: Label number 7.

Charleston
1886
M7.5

147

material amplification

non-rigid materials amplify seismic waves
Jello vs. Cake

148

Give an example of a place affected by material amplification.

Petaluma, CA (near the San Andreas Fault)

149

What causes structural damage in an earthquake?

shaking

150

What factors decrease structural damage?

buildings made of wood (rather than concrete), buildings with steel framework

151

liquefaction

saturated sediment behaves like a liquid

152

Why are San Francisco and Tokyo so affected by liquefaction?

The San Francisco bay area is landfill.
Tokyo is built on a sediment-filed lake.

153

landslides

trigger slopes on the verge of failure

154

Why are fires an earthquake hazard?

gaslines

155

When are tsunamis created?

when the ocean volume changes rapidly (fault, landslide, volcanic eruption)

156

How are tsunamis different from wind waves?

tsunamis have longer periods (20-30 minutes) while wind waves have shorter periods (10-20 seconds)

157

magma

molten rock BELOW the surface

158

lava

molten rock ON the surface

159

pyroclastic debris

hot lava, ash, gas, and rocks ejected by explosive eruptions

160

Why does magma rise to the surface?

magma is lighter (less dense) than rock

161

Where is magma produced?

beneath earth's crust

162

What two main factors determine the explosivity of a volcanic eruption?

1. water (--> steam)
2. viscosity

163

viscosity

resistance to flow

164

What type of volcano is not explosive, has gentle slopes, has little or no summit crater, and involves basalt?

shield volcano

165

What type of volcano is explosive, has steep slopes, has a distinct summit crater, and involves andesite?

composite volcano

166

Describe the explosivity of a shield volcano.

not explosive, low viscosity & low water

167

Describe the explosivity of a composite volcano.

explosive, high viscosity & high water

168

How much pyroclastic debris does a shield volcano have?

less than 10%

169

How much pyroclastic debris does a composite volcano have?

up to 50%

170

Which type of volcano erupts andesite?

composite volcano

171

Which type of volcano erupts basalt?

shield volcano

172

Describe the lava from a shield volcano.

runny

173

What type of volcanoes are present in Hawaii?

shield volcanoes

174

What type of volcano is Mount St. Helens?

composite volcano

175

steep slopes = ___ viscosity magma

high

176

low viscosity

flows easily

177

high viscosity

flows slowly

178

low viscosity + low water = ?

flows (Hawaii)

179

low viscosity + some water = ?

fountains

180

high viscosity + high water = ?

explosive (as water converts to steam)

181

high viscosity + low water = ?

thick obsidian flow (glass) (uncommon)

182

Where is Mount St. Helens located?

Cascades, WA

183

Basaltic eruptions from shield volcanoes flow ____.

easily

184

Andesite eruptions from composite volcanoes are ___ and ____.

thick; pasty

185

How hazardous are lava flows?

destructive, but generally few fatalities

186

ash

small pieces of rock and glass

187

Describe an ash fall.

affects large areas, very abrasive, conductive when wet, heavy (like concrete)

188

Pyroclastic materials: bombs

partially molten magma freezes in air

189

What are pyroclastic flows made up of?

ash, rock, and very hot gasses

190

What is the deadliest hazard in explosive eruptions?

bombs & pyroclastic flows

191

How fast do pyroclastic flows travel?

up to 150 mph down slope

192

lahar

volcanic mudflow, flowing volcanic debris (more than 60% rock)

193

Which volcanic hazard can occur with or without an eruption?

lahar

194

How fast do lahars travel?

up to 40 mph

195

What types of earthquakes are found at a divergent boundary?

shallow tensional

196

What type of earthquakes are found at a convergent boundary?

compressional

197

What types of volcanoes are found at a convergent ocean-ocean boundary?

explosive
composite

198

What types of volcanoes are found at a convergent ocean-continent boundary?

explosive
composite

199

What types of volcanoes are found at a convergent continent-continent boundary?

usually no volcanoes

200

What types of volcanoes are found at a divergent boundary?

shield volcanoes

201

What type of volcanoes form at transform boundaries?

generally no volcanoes

202

What type of earthquakes are found at transform boundaries?

shallow to intermediate

203

What type of volcanoes are formed at a hot spot?

string of inactive volcanoes, volcanic centers get older away from current hot spot location

204

P-wave

Primary (first to show up after earthquake)
Pressure, Pushing
(Slinky)
First waves to arrive somewhere else on earth after there's been an earthquake

205

S-wave

Secondary (after p-wave)
Sideways
(Jump rope)

206

Which type of wave can move through a fluid?

P-wave

207

When was the main Mount St. Helens eruption?

May 18th, 1980

208

What clues suggested that Mount St. Helens would erupt in 1980?

March 20 - intrusion of magma generates tremors
April 30 - continued intrusion produces bulge

209

How big is the Mount St. Helens caldera?

1 mile across

210

caldera

crater left in erupted volcano the size of the magma chamber

211

How big is the Yellowstone caldera?

50 miles across

212

What do the tectonic plates slide around on?

asthenosphere

213

What features can result from a mantle plume head eruption?

Land: continental flood basalt
Ocean: oceanic plateau

214

What features can result from a mantle plume tail eruption?

Land: hot spot volcanoes
Ocean: linear island chain

215

Which is more dense, the crust or the mantle?

mantle

216

What type of crust has more andesite? Where?

continental; near subduction zones, continental arcs

217

What type of crust gets "recycled"

oceanic

218

Where does peridotite come from?

mantle

219

plate tectonics

the idea that the Earth's surface is composed of rigid plates that move relative to one another

220

How many major plates is the lithosphere divided into?

8-10

221

What is the most common type of plate boundary?

divergent

222

What is the least common type of plate boundary?

transform

223

Rocks are ___ in compression and ___ in tension.

strong; weak

224

What are 3 ways to melt the mantle?

1. Reduce the pressure
2. Add water
3. Add heat

225

Which way to melt the mantle is the least common?

adding heat

226

Which type of plate boundary is "how to make an ocean"

divergent

227

Complete the sentence: The Himalayas are the result of...

a continent-continent convergent boundary creating a crumple zone.

228

Give an example of a super volcano.

Yellowstone

229

The epicenter is located ____ the focus.

above

230

T/F: A focus means there's a fault.

false

231

T/F: Faults are often angled.

true

232

What is the largest earthquake ever recorded?

Chile, 1960
M9.5
5700 deaths mostly from tsunami

233

When is an intraplate earthquake likely to occur?

when the plate is being pulled in two opposing directions and pushed in the other two
so it's shaped like this -> 0
rather than this -> O

234

focus

spot where the rock broke

235

____ ____ create the biggest earthquakes.

Subduction zones

236

Non-rigid materials ___ seismic waves. This is called ____ ____.

amplify; material amplification

237

Gas ___ in a liquid becomes gas bubbles in a liquid.

dissolved