Geological Hazards Flashcards

1
Q

How does convection play a role in both the mantle and the atmosphere?

A

Heat transfer in a liquid (magma, ocean water, and air).
Can come from the sun and effect the air.
Hot things rise & cold things sink.
Convection of air in the troposphere.
Influences where wet and dry areas are.

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2
Q

How do ocean surface temperatures play a role in weather?

A

El Nino: Abnormal warming in equatorial waters = wetter than normal conditions across the southern part of North America.
La Nina: Abnormal cooling in equatorial waters = dryer than normal conditions across the southern part of North America.

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3
Q

How does the density of material affect its buoyancy? How does this relate to convection?

A

Hot things rise; cold things sink.
Starts a cycle that leads to convection.
The thing’s temperature effects its density: more heat = less dense; less heat = more dense.

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4
Q

What happens to the density of water when it freezes?

A

It decreases because ice has a lower density than water which is why it rises in drinks.

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5
Q

Why are salinity and temperature important with regard to deep-water currents?

A

Deep ocean currents are driven by density. Salinity effects density. There is a large current that runs around the whole planet. Salt water has a different density than fresh water. If this current is changed, the weather can be changed. Fresh water is colder than salt water.

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6
Q

What is Pangea?

A

A supercontinent that existed during the late Paleozoic and early Mesozoic eras that includes all of the landmasses.

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7
Q

Why is the discovery of fossil remains of Mesosaurus in both South America and Africa, but nowhere else, important support for continental drift?

A

The Mesosaurus was a four legged creature who couldn’t swim. If they are found on both continents, it must have walked across which prove that the continents were once stuck together.

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8
Q

Radioactive Decay

A

The process by which an atomic nucleus of an unstable atom loses energy by emitting ionizing particles (ionizing radiation).

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9
Q

Mantle Convection

A

Heat is carried from the interior of the Earth to the surface. Plates are continuously being created and consumed at their opposite plate boundaries. Accretion occurs as mantle is added to the growing edges of a plate, usually associated with seafloor spreading. This hot added material cools down by conduction and convection of heat. At the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of subduction at an ocean trench. It is because the mantle can convect that the tectonic plates are able to move around the Earth’s surface.

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10
Q

Divergent Margins (plate tectonics)

A

Plates move away from each other
Lava comes up between them
Mostly happens in oceanic plates
Newer rock forms between them

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11
Q

Transform Margins (plate tectonics)

A

Plates slide next (past) each other

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12
Q

Convergent Margins (plate tectonics)

A

One plate is being pulled under another plate
One plate has a higher density than the other
The higher density plates go underneath the lesser density plates

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13
Q

Hot-spot volcanism

A

Hawaii
Hot Spot volcanoes are recognized by an age progression from one end of the chain to the other. An active volcano commonly serves as an “anchor” at one end of the chain.

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14
Q

Atmosphere

A

Made of gas
Gets thinner
Separated into layers

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15
Q

Atmosphere compostition

A

Nitrogen
Oxygen
Argon
Carbon dioxide

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16
Q

Atmosphere layers

A
Defined by thermal characteristics, density, composition, and movement.
Exosphere (highest)
Thermosphere
Mesosphere
Stratosphere
Troposphere (lowest)
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17
Q

Exosphere (atmosphere layers)

A

Gas escapes to space

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18
Q

Thermosphere (atmosphere layers)

A

Very small amounts of gas

Aurora

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19
Q

Mesosphere (atmosphere layers)

A

Small amounts of gas

Slows meteors down

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20
Q

Stratosphere (atmosphere layers)

A

Ozone created

NO CONVECTION

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21
Q

Troposphere (atmosphere layers)

A

All weather happens here

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22
Q

Hydrosphere

A

Water (oceans, lakes, rivers, groundwater, and ice)

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23
Q

Lithosphere

A

Earth’s crust

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24
Q

“Great Ocean Conveyor Belt”

A

Constantly moving system of deep-ocean circulation driven by temperature and salinity.
Cold, salty water is dense and sinks to the bottom of the ocean while warm water is less dense and rises to the surface.
The ocean conveyor gets it “start” in the Norwegian Sea, where warm water from the Gulf Stream heats the atmosphere in the cold northern latitudes. This loss of heat to the atmosphere makes the water cooler and denser, causing it to sink to the bottom of the ocean.

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25
Surface ocean currents
Driven by wind Northern Hemisphere: clockwise rotation Southern Hemisphere: counterclockwise rotation
26
Phases of Matter
Solids: atoms bound in a single crystallized structure, very little movement, + heat --> liquid. Liquid: moderate speed of atoms, + heat = gas. Gas: very fast moving atoms, vapor Takes more energy to go from a solid to a liquid.
27
Sublimination (phases of matter)
Going directly from a solid to a vapor.
28
Coriolis Effect
Leads to deflection of moving air masses because the earth is rotating underneath the atmosphere Northern Hemisphere = moves right Southern Hemisphere = moves left
29
Hadley Cell
A pattern of atmospheric circulation in which warm air rises near the equator, cools as it travels poleward at high altitude, sinks as cold air, and warms as it travels equatorward.
30
How does the volatile content of magma affect the explosiveness of a volcano?
Shaking a soda
31
How does rock chemistry affect the explosively of a volcano?
The higher the silica content, the more explosive it is.
32
Mafic rock
Low silica content
33
Intermediate rock
Moderate silica content
34
Felsic rock
High silica content
35
Basalt rock
Low silica content | Mafic rock
36
Andesite rock
Moderate silica content | Intermediate rock
37
Dacite rock
Moderate to high silica content | Intermediate rock
38
Rhyolite
Very high silica content | Felsic rock
39
How do volcanoes relate to plate tectonics?
Volcanoes form as a result of plate tectonics. When plates are pushing, pulling, and grinding they cause volcanoes. Magma that reaches the surface of the earth produces volcanoes where plates collide or spread apart.They form either at mid-ocean ridges - divergent plate margins, or above subduction zones. A few form within plates as a result of hot-spot activity.
40
What is Mount Mazama? Why is it important for absolute age dating?
Need igneous rock?
41
How fast can a pyroclastic density cloud move?
700 km/h (450 mph)
42
Why does Yellowstone National Park have geysers?
Because there is a volcano underneath. The geyser basin is squeezed between two lava flows.
43
Phreatomagmatic
Juvenile forming eruptions as a result of interaction between water and magma.
44
What would happen if a volcano erupted under a glacier?
Eyjafjallajökull Glacier is melted into a lake by the rising lava. The water quickly cools the lava, resulting in pillow lava shapes. Pillow lava breaks off and rolls down the volcano slopes.
45
Viscosity
A material's resistance to flow | Difference between water and honey
46
Hawaiian & Icelandic (eruptive styles)
Gas poor Fissures eruptions Long duration
47
Strombolian (eruptive styles)
Slightly viscous Gas poor Localized on fissures Near continuous
48
Vulcanian (eruptive styles)
Moderately viscous Moderate gas Isolated Intermittent activity
49
Plinian (eruptive styles)
``` Very destructive Very viscous Very high gas content Isolated Episodic activity Can produce shockwave Opens with a pyroclastic flow ```
50
Shield volcano
Effusive eruption | Broad flanks formed by lava flow
51
Causes of eruption
Magma chamber size Volatile content Melting due to temperature, pressure, and water content Injection of mafic magma into felsic magma
52
Pyroclastic flow
An incandescent, ground hugging cloud of pumice and dust that flows down the flank of a volcano Hazards: eruptive column collapse & large scale dome collapse
53
Lahar
Mudflow involving volcaniclastic material
54
Controls on Volcanic Styles
Silica content Volatile content Major minerals Different rock types
55
Effusive eruption vents
``` Fountains curtain of fire, fissure, lava lakes, splatter cones, hornitio ```
56
Fountains (effusive eruption vents)
Eruption focused at a point
57
What makes a volcano effusive?
Low gas content | Mafic composition
58
Intermediate rock
Moderate silica content
59
Felsic rock
High silica content
60
Basalt rock
Low silica content | Mafic rock
61
Andesite rock
Moderate silica content | Intermediate rock
62
Dacite rock
Moderate to high silica content | Intermediate rock
63
Rhyolite
Very high silica content | Felsic rock
64
How do volcanoes relate to plate tectonics?
Volcanoes form as a result of plate tectonics. When plates are pushing, pulling, and grinding they cause volcanoes. Magma that reaches the surface of the earth produces volcanoes where plates collide or spread apart.They form either at mid-ocean ridges - divergent plate margins, or above subduction zones. A few form within plates as a result of hot-spot activity.
65
What is Mount Mazama? Why is it important for absolute age dating?
Need igneous rock?
66
How fast can a pyroclastic density cloud move?
700 km/h (450 mph)
67
Why does Yellowstone National Park have geysers?
Because there is a volcano underneath. The geyser basin is squeezed between two lava flows.
68
Phreatomagmatic
Juvenile forming eruptions as a result of interaction between water and magma.
69
What would happen if a volcano erupted under a glacier?
Eyjafjallajökull Glacier is melted into a lake by the rising lava. The water quickly cools the lava, resulting in pillow lava shapes. Pillow lava breaks off and rolls down the volcano slopes.
70
Viscosity
A material's resistance to flow | Difference between water and honey
71
Hawaiian & Icelandic (eruptive styles)
Gas poor Fissures eruptions Long duration
72
Strombolian (eruptive styles)
Slightly viscous Gas poor Localized on fissures Near continuous
73
Vulcanian (eruptive styles)
Moderately viscous Moderate gas Isolated Intermittent activity
74
Plinian (eruptive styles)
``` Very destructive Very viscous Very high gas content Isolated Episodic activity Can produce shockwave Opens with a pyroclastic flow ```
75
Shield volcano
Effusive eruption | Broad flanks formed by lava flow
76
Causes of eruption
Magma chamber size Volatile content Melting due to temperature, pressure, and water content Injection of mafic magma into felsic magma
77
Pyroclastic flow
An incandescent, ground hugging cloud of pumice and dust that flows down the flank of a volcano Hazards: eruptive column collapse & large scale dome collapse
78
Lahar
Mudflow involving volcaniclastic material
79
Controls on Volcanic Styles
Silica content Volatile content Major minerals Different rock types
80
Effusive eruption vents
``` Fountains curtain of fire, fissure, lava lakes, splatter cones, hornitio ```
81
Fountains (effusive eruption vents)
Eruption focused at a point
82
What makes a volcano effusive?
Low gas content | Mafic composition