Hazardous Earth Topic 1

Question 1

Continental Crust

Answer 1

The thick part of the earth’s crust which forms the large land masses. It is generally older and more complex than the oceanic crust. It cannot be destroyed or renewed.

Question 2

Oceanic Crust

Answer 2

The uppermost layer of the oceanic proportion of a tectonic plate. The oceanic crust is denser than the continental crust and it can sink and be renewed and destroyed.

Question 3

Inner Core

Answer 3

The inner core is the hottest part of the earth. It is solid and is made up of iron and nickel with temperatures up to 5500c. It is 1250km thick.

Question 4

Outer Core

Answer 4

The outer core is a liquid layer and is also made from iron and nickel. The temperature is similar to the inner core. It is 2300km thick.

Question 5

Mantle

Answer 5

The mantle is approximately 2900km thick. It is made from semi molten rock called the magma and reaches temperatures up to 3000c. The upper parts are hard and lower down it is soft and beginning to melt.

Question 6

Crust

Answer 6

The crust is a thin layer 0-60km thick. The crust is the solid rock layer which we live on. It is 1% of the planets mass. Two different crusts oceanic and continental.

Question 7

Lithosphere

Answer 7

Crust and the upper part of the mantle. One of the coolest layer 0-100c and is made of rock. It is 0-100km thick.

Question 8

Asthenosphere

Answer 8

Can be described as plastic like. It is less rigid than the lithosphere. It is made of semi molten due to the heat. High pressure on the material.

Question 9

Radioactive Decay

Answer 9

Atoms of elements such as potassium, uranium and thorium release particles from their nuclei and give off heat.

Question 10

Convection Currents

Answer 10

A stream of fluid moved by heat.

Question 11

Convergent (destructive) boundary

Answer 11

The oceanic and continental plates move towards each other. The denser oceanic crust goes underneath the lighter continental crust. Example Andes Mountains.

Very explosive and destructive volcanoes.
Very destructive earthquakes.

Question 12

Divergent (constructive) boundary

Answer 12

Two tectonic plates moving away from each other.

Small earthquakes.
Not very explosive or dangerous volcanoes.

Question 13

Conservative boundary

Answer 13

Two plates try to slowly slide past each other, this creates friction.

Destructive earthquakes.
No volcanoes.

Question 14

Collision boundary/margin

Answer 14

Two plates both continental move towards each other. As continental crust cannot be destroyed, then the land is pushed upwards to form high ‘fold’ mountains. Example the Himalayas Mountains.

Destructive earthquakes.
Rare volcanoes.

Question 15

Hot spot

Answer 15

Where ‘plumes’ of magma are rising to the surface.

Question 16

Mercalli scale

Answer 16

A scale using descriptive words when talking about earthquakes.

Question 17

Primary impact

Answer 17

The direct impacts of an event, usually occurring instantly.

Question 18

Secondary impact

Answer 18

The indirect impacts of an event usually occurring in hours, weeks, months or years after the event.

Question 19

Shield volcano

Answer 19

A broad volcano with gently sloping sides.

Question 20

Composite volcano

Answer 20

A large, steep volcano built up of alternating layers of lava and ash.

Question 21

Magnitude

Answer 21

The power of the earthquake (how much the ground shakes).

Question 22

Focus

Answer 22

Where the earthquake happens.

Question 23

Epicentre

Answer 23

The plate directly above the focus (on the surface).

Question 24

Seismometer

Answer 24

This is the instrument which records the earthquake.

Question 25

Pyroclastic flow

Answer 25

A cloud of smoke which also contains fireballs and rock.

Question 26

High viscosity

Answer 26

‘Treacly’ gasy lava.

Question 27

Low viscosity

Answer 27

‘Runny’ lava.