Hazardous Earth Flashcards

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1
Q

Name the earths layers

A

Crust
Lithosphere
Upper mantle (the asthenosphere)
The lower mantle
The outer core
The inner core

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2
Q

Description of the inner core

A

Solid ball of iron and nickel
Under huge amounts of pressure
Contains uranium and thorium(responsible for the earths internal energy)

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3
Q

Outer core description

A

Molten liquid layer of iron and nickel that surrounds the inner core
Heat from the inner core creates convection currents

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4
Q

Mantle description

A

Largest layer behaves like a dense fluid
The upper layer( asthenosphere) constantly moves and flows due to convection currents

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5
Q

Lithosphere description

A

Solid rock
0-100 km thick (continental)
6-8km thick ( oceanic

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6
Q

How are convection currents formed

A

Energy from radioactive decay in the core heats up the lower mantle

The hot liquid becomes less dense than its surroundings so it rises upwards

It becomes more dense, therefore sinks back to the bottom

It is heated back again and the cycle continues

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7
Q

Divergent

A

Move away

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8
Q

Convergent

A

Move toward each other —>

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9
Q

Conservative

A

Slides past each other

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10
Q

What happens when two plates move apart

A

Magma rises in between the gap lava pours out into the surface
Volcanoes form in areas where lava pours out
Can happen in both continental and oceanic crust

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11
Q

What happens in convergent

A

The plates move towards each other causing one plate to go under another where the one which Subducts is destroyed always oceanic

Leaves an ocean trench
Friction causes earthquakes
Oceanic crust is melted creating magma
Which causes pressure to build up overtime creating an explosive volcano

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12
Q

What happens when an convergent plate movement occurs between oceanic and an oceanic

A

The denser one sinks below which may cause islands in the ocean to form

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13
Q

What happens when an convergent plate movement occurs between continental and an continental

A

Neither sink below instead they rise up wards creating fold mountains ( large steep mountains )

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14
Q

What happens at a conservative plate boundary

A

They create friction because the move side by side
Is both plates get stuck overtime pressure builds up when the move the create very large earthquakes and tsunamis

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15
Q

What are hotspots

A

They are areas of volcanic activity not related to plate boundaries

Hot magma from the mantle rise and burn through weaker parts of the crust which can create volcanoes and islands

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16
Q

Shield volcano characteristics

A

Non-explosive
Fast flowing Runny lava
Has low thickness of lava
Shallow sides

17
Q

Composite volcano characteristics

A

Very explosive
Extremely hot gases and ash
Has a very strong pyroclastic flow

18
Q

What’s used to measure earthquake strength

A

Richter scale

19
Q

How do tsunamis form

A

When an oceanic crust is jolted during an earthquake all the water above is displaced

Water travels fast but with low amplitude

As it gets closer to the coast the sea level decreases so there is friction between the sea bed and the waves

This causes waves to slow down and gain height creating a tsunami

20
Q

how can you predict when a volcano is likely to erupt

A

Seismometers, which measure vibrations in the ground near a volcano, when they are high there is a strong chance of an eruption

21
Q

Which factors affect the amount of damage done by an earthquake?

A

The level of development
The population density
Building infrastructure

22
Q

How many deaths were there at Haiti?

A

around 300,000 deaths and 300,000 injured

23
Q

How many people were made homeless by the Haiti Earthquake?

A

1.5 million were made homeless

24
Q

Describe the Volcanoes divergent plates form

A

Non-explosive, Runny and fast lava, basaltic lava. usually shield volcanoes

25
Q

Describe the Volcanoes Convergent plates form

A

Very explosive, thick slow lava, andesitic lava. usually composite volacnoes

26
Q

Describe the Volcanoes conservative plates form

A

No volcanoes as no crust is being destroyed and no magma generated

27
Q

Describe the earthquakes formed in divergent plates

A

Smaller earthquakes as there is less friction. (5-6 on Richter scale)

28
Q

Describe the earthquakes formed in convergent plates

A

Very strong earthquakes. they may be deep underground making them weaker. (up to 9.5 on Richter scale)

29
Q

Describe the earthquakes formed in conservative plates

A

Very strong earthquakes, they can be shallow meaning that they could cause more damage. (up to 8.5 on Richter scale)